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Ambient Light Reduction Strategy to Synthesize Silver Nanoparticles and Silver-Coated TiO2

Ambient Light Reduction Strategy to Synthesize Silver Nanoparticles and Silver-Coated TiO2
Ambient Light Reduction Strategy to Synthesize Silver Nanoparticles and Silver-Coated TiO2

Ambient Light Reduction Strategy to Synthesize Silver Nanoparticles and Silver-Coated TiO2with Enhanced Photocatalytic and Bactericidal Activities Lizhi Zhang,?Jimmy C.Yu,*,?Ho Yin Yip,?,§Quan Li,?Kwan Wai Kwong,?

An-Wu Xu,?and Po Keung Wong§

Department of Chemistry and Environmental Science Program,Department of Physics, and Department of Biology,The Chinese University of Hong Kong,Shatin,

New Territories,Hong Kong,China

Received July22,2003.In Final Form:September2,2003

Under ambient light illumination,silver nanoparticles can be synthesized by a triblock copolymer induced reduction of[Ag(NH3)2]+ions in ethanol.Conventional chemical reducing agents,thermal treatment,and radiation sources are no longer necessary in this novel approach.A possible mechanism was proposed to explain the formation and stabilization of silver nanoparticles based on UV-vis absorption spectra and transmission electron microscopy results.This novel ambient light route has been successfully applied to deposit silver nanoclusters on TiO2.Silver nanoclusters of about2nm in size were found to strongly anchor to the TiO2nanoparticles with high dispersion.The resulting silver-coated TiO2material with optimal silver loading showed enhanced photocatalytic and bactericidal activities compared to the uncoated TiO2. The reasons for the enhancements of the activities were discussed.

Introduction

The unique physical and chemical properties of na-nometer-sized metal colloids have been well documented and proposed for a wide variety of applications.1Metal colloid formation in micelles of amphiphilic block copoly-mers is a promising new trend in modern science.2A variety of amphiphilic diblock copolymers have been utilized for the synthesis of metal nanoparticles.However, tedious post-treatments such as chemical reduction,laser photolysis,and thermal treatment are necessary for the reduction of metal ions in micelles of the amphiphilic block copolymers.2-7

Metal nanoparticles highly dispersed on an active oxide are a classic example of a bifunctional catalyst in which chemisorptive activation of the substrate by the metal is coupled to oxygen atom transfer mediated by the active oxide.8These nanocomposite systems of metal particles on various oxide supports are of great importance for academic research and industrial applications.9Noble metal-TiO2systems have attracted much more interest due to their application for improving properties of metal catalysis or TiO2photocatalysis.10,11For instance,silver-TiO2catalysts are used industrially for the epoxidation of ethylene to ethylene epoxide and for the oxi-dehydroge-nation of methanol to formaldehyde,as well as for the low-temperature selective oxidation of ammonia to ni-trogen because of its inexpensiveness.11Silver-coated TiO2 materials are traditionally prepared by precipitation-deposition,incipient wet-impregnation,the sol-gel method, or photoreduction under UV irradiation.12The last method uses an irradiative source and may cause aggregation of silver particles,while the other three methods are tedious and energy-consuming because thermal post-treatment is necessary,which may also result in sintering and/or aggregation of silver particles.13,14Therefore,it is a challenge to develop convenient and environmentally friendly methods to prepare silver-coated TiO2without silver aggregation.

Water-soluble triblock copolymers of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)type (PEO-PPO-PEO)are known to have demonstrated excellent properties for the synthesis of mesoporous materials.15Very recently,the Pluronic triblock copolymer series(PEO)x(PPO)y(PEO)x was used as surfactant tem-plates in the preparation of CdS nanoparticles and nanorods.16In this report,we demonstrate for the first

*To whom correspondence should be addressed.E-mail:jimyu@ https://www.wendangku.net/doc/6a1303184.html,.hk.Fax:+852-********.

?Department of Chemistry and Environmental Science Program.

?Department of Physics.

§Department of Biology.

(1)Nichols,W.T.;Keto,J.W.;Henneke, D. E.;Brock,M. F.; Malyavanatham,G.;Becker,M.F.;Glicksman,H.D.Appl.Phys.Lett. 2001,78,1128.

(2)Bronstein,L.;Chernyshov, D.;Valetsky,P.;Tkachenko,N.; Lemmetyinen,H.;Hartmann,J.;Fo¨rster,https://www.wendangku.net/doc/6a1303184.html,ngmuir1999,15,83.

(3)Chernyshov,D.M.;Bronstein,L.M.;Borner,H.;Berton,B.; Antonietti,M.Chem.Mater.2000,12,114and references therein.

(4)Boontongkong,Y.;Cohen,R.E.Macromolecules2002,35,3647 and references therein.

(5)Mo¨ssmer,S.;Spatz,J.P.;Mo¨ller,M.;Aberle,T.;Schmidt,J.; Burchard,W.Macromolecules2000,33,4791and references therein.

(6)Moffitt,M.;Eisenberg,A.Chem.Mater.1995,7,1178.Moffitt, M.;McMahon,L.;Pessel,V.;Eisenberg,A.Chem.Mater.1995,7,1185.

(7)Hashimoto,T.;Harada,M.;Sakamoto,N.Macromolecules1999, 32,6867.

(8)Rolison,D.R.Science2003,299,1698.

(9)De Oliveira,A.L.;Wolf,A.;Schu¨th,F.Catal.Lett.2002,73,157.

(10)Tada,H.;Teranishi,K.;Inubushi,Y.I.;Ito,https://www.wendangku.net/doc/6a1303184.html,mun. 1998,2345.Tada,H.;Teranishi,K.;Inubushi,Y.I.;Ito,https://www.wendangku.net/doc/6a1303184.html,ngmuir 2000,16,3304.

(11)Gang,L.;Anderson,B.G.;Grondelle,J.;van Grondelle,J.;van Santen,R.A.Appl.Catal.,B2002,40,101and references therein.

(12)Claus,P.;Hofmeister,H.J.Phys.Chem.B1999,103,2766. Traversa,E.;Vona,M.L.D.;Nunziante,P.;Licoccia,S.J.Sol.-Gel Sci. Technol.2000,19,733.Keleher,J.;Bashant,J.;Heldt,N.;Johnson,L.; Li,Y.Z.World J.Microbiol.Biotechnol.2002,18,133.

(13)Vamathevan,V.;Amal,R.;Beydoun,D.;Low,G.;McEvoy,S.J. Photochem.Photobiol.,A2002,148,233.

(14)He,C.;Yu,Y.;Hu,X.F.;Larbot,A.Appl.Surf.Sci.2002,200, 239.

(15)Zhao,D.;Feng,J.;Huo,Q.;Melosh,N.;Fredrickson,G.H.; Chmelka,B.F.;Stucky,G.D.Science1998,279,548.Kim,J.M.;Stucky, https://www.wendangku.net/doc/6a1303184.html,mun.2000,1159.Feng,P.;Bu,X.;Stucky,G.D.;Pine,

D.J.J.Am.Chem.Soc.2000,122,994.

(16)Yang,C.S.;Awschalom,D.D.;Stucky,G.D.Chem.Mater.2002, 14,1277.

10372Langmuir2003,19,10372-10380

10.1021/la035330m CCC:$25.00?2003American Chemical Society

Published on Web10/21/2003

time that a neutral amphiphilic triblock copolymer(PEO20-PPO70PEO20,P123)can induce reduction of[Ag(NH3)2]+ ions in ethanol by ambient light illumination.Silver nanoparticles can thus be prepared without any post-reduction treatments.Moreover,this method can be utilized to deposit silver nanoclusters(~2nm)on TiO2 nanoparticles without silver aggregation.The resulting silver-coated TiO2shows enhanced photocatalytic activity in the oxidation of acetone in air and better bactericidal effects on Micrococcus lylae(M.lylae)in water in comparison with the uncoated TiO2.

Experimental Section

Synthesis of Silver Nanoparticles.The triblock copolymer was obtained from Aldrich.All reagents used were of analytical purities.A0.1M[Ag(NH3)2]+aqueous solution was prepared from the reaction of1.8mL of concentrated ammonia and0.01 mol of AgNO3in water.Stoichiometric amounts of0.1M[Ag-(NH3)2]+aqueous solution were added to a freshly prepared2.5% w/v P123ethanolic solution(solution1),shaken gently by hand, and then illuminated under ambient light coming from the laboratory lamps or aged in the dark without stirring,respec-tively.The intensity of ambient light in the lab was2.43W/m2 as measured by a light meter(LI-COR,model LI-250,USA).

Synthesis of Silver-Coated TiO2.TiO2powder(1g)(P25, Degussa)was suspended in40mL of0.1%(w/v)P123ethanolic solution,followed by addition of an appropriate amount(0.25, 0.5,or1mL)of0.1M[Ag(NH3)2]+aqueous solution.The suspension was then illuminated under ambient light for1h under magnetic stirring.During illumination,the suspension changed from white to purple.The purple powder was recovered by centrifugation,washed with ethanol,and finally dried in an oven at100°C.Silver-coated TiO2samples with different Ag/Ti molar ratios were thus prepared and denoted as AT-0.25,AT-0.5,and AT-1according to the volume of0.1M[Ag(NH3)2]+ aqueous solution used in the preparation.

Characterization.The absorption spectra of silver colloids were recorded with a Varian Cary100Scan UV-Visible system. The Varian Cary100Scan UV-Visible system equipped with a Labsphere diffuse reflectance accessory(USRS-99-010)was also used to obtain the reflectance spectra of the silver-coated TiO2 catalysts over a range of200-800nm.

Transmission electron microscopy(TEM)and high-resolution transmission electron microscopy(HRTEM)studies were carried out on a Philips Tecnai20St electron microscopy instrument. The samples for TEM and HRTEM were prepared by dispersing the final powders in ethanol;the dispersion was then dropped on carbon-copper grids.

Infrared spectra of the solutions dropped on KBr pellets were recorded on a Nicolet Magna560FTIR spectrometer at a resolution of4cm-1.

The nitrogen adsorption and desorption isotherms at77K were measured using a Micromeritics ASAP2010system after the samples were vacuum-dried at200°C overnight.

X-ray photoelectron spectroscopy(XPS)measurements were performed in a VG Scientific ESCALAB Mark II spectrometer equipped with two ultrahigh-vacuum chambers.All binding energies were referenced to the284.8-eV C1s peak of the surface adventitious carbon.

Measurements of Photocatalytic Activity.The photo-catalytic activity experiments on the silver-coated and uncoated TiO2for the oxidation of acetone in air were performed at ambient temperature using a7000-mL reactor.The photocatalysts were prepared by coating an aqueous suspension of photocatalysts onto three dishes with a diameter of5.0cm.The weight of the photocatalysts used for each experiment was kept at0.3g.The dishes containing the photocatalysts were pretreated in an oven at100°C for1h and then cooled to room temperature before use.

After the dishes coated with the photocatalysts were placed in the reactor,a small amount of acetone was injected into the reactor with a syringe.The reactor was connected to a pump and a dryer containing CaCl2for adjusting the starting concentration of acetone and controlling the initial humidity in the reactor. The analysis of acetone,carbon dioxide,and water vapor concentration in the reactor was performed with a Photoacoustic IR Multi-gas Monitor(INNOVA Air Tech Instruments model 1312).The acetone vapor was allowed to reach adsorption equilibrium with the photocatalysts in the reactor prior to experimentation.The initial concentration of acetone after the adsorption equilibrium was400ppm,which remained constant until a15-W365-nm UV lamp(Cole-Parmer Instrument Co.)in the reactor was turned on.The initial concentration of water vapor was1.20(0.01vol%,and the initial temperature was25 (1°C.

Preparation of Bacterial Culture.M.lylae,a Gram-positive bacterium that was isolated in our laboratory,was used as a model bacterium in the experiment.It was incubated in10% trypticase soy broth(TSB)at30°C with200rpm agitation for 24h.The culture was washed with0.9%saline by centrifugation at12000rpm for5min at25°C,and the pellet was resuspended in saline.The cell suspension was adjusted in centrifuged tube to the required cell concentration(3×107colony-forming units (cfu)/mL).

Measurements of Bactericidal Activity.The photocatalyst was added to0.9%saline in a conical flask and homogenized by sonication.The suspension was then sterilized by autoclaving at 121°C for20min and mixed with the prepared cell suspension after cooling.The final photocatalyst concentration was adjusted to0.2mg/mL,and the final bacterial cell concentration was3×106cfu/mL.The photocatalytic reaction was started by irradiating the mixture with near-UV light and stopped by switching off the light.Each set of experiments was performed in triplicate.The light source used was a15-W365-nm UV lamp(Cole-Parmer Instrument Co.)placed close to the side of the flask.The reaction mixture was stirred at300rpm with a magnetic stirrer to prevent settling of the photocatalyst.A bacterial suspension without photocatalyst was irradiated as a control,and the reaction mixture with no UV irradiation was used as a dark control.Before and during the light irradiation,an aliquot of the reaction mixture was immediately diluted with0.9%saline and plated on TSB agar.The colonies were counted after incubation at37°C for48 h.

Results and Discussion

Triblock Copolymer Induced Formation of Silver Nanoparticles by Ambient Light Illumination.In the absence of P123,a10-4M[Ag(NH3)2]+ethanolic solution remains colorless and no significant change can be detected in the absorption spectra of this solution either after ambient light illumination or after aging in the dark for several weeks.This indicates that reduction of[Ag(NH3)2]+ ions does not take place.However,the clear solution will gradually turn yellow and then reddish brown when a 10-4M[Ag(NH3)2]+ethanol solution containing2.5%(w/ v)P123(solution2)is illuminated by ambient light.A characteristic silver plasmon band appears at400nm on the absorption spectra,indicating the formation of metallic silver in the solution.Interestingly,no coloration change takes place if solution2is aged in the dark,and no silver plasmon band can be detected on absorption spectra (Figure1).When the[Ag(NH3)2]+concentration in this 2.5%(w/v)P123ethanolic solution is increased from10-4 to10-3M(solution3,that is,10-3M[Ag(NH3)2]+ethanolic solution containing2.5%(w/v)P123),the formation of a silver colloid occurs instantly.The rapid formation of metallic silver is confirmed by UV-vis absorption spectra (Figure2).Such a sensitive response to ambient light implies that this method may find potential applications in the photographic and micropatterning fields.17,18In the absence of P123,no formation of silver colloid was observed even in the10-3M[Ag(NH3)2]+ethanolic solution under ambient light illumination.

(17)Tani,T.Photographic sensitivity;Lapp,M.,Nishizawa,J.I., Snavely,B.B.,Stark,H.,Tam,A.C.,Wilson,T.,Eds.;Oxford University Press:New York,1995;pp11-21.

(18)Saito,N.;Haneda,H.;Sekiguchi,T.;Ohashi,N.;Sakaguchi,I.; Koumoto,K.Adv.Mater.2002,14,418.

Synthesis of Ag Nanoparticles under Ambient Light Langmuir,Vol.19,No.24,200310373

It has been reported that PEO-type nonionic surfactants could slowly reduce Ag +ions to metal Ag through oxidation of their oxyethylene groups.19-21The oxidized surfactants could be detected by an infrared spectrometer.19To check whether the hydrophilic PEO end blocks could reduce [Ag-(NH 3)2]+ions,we recorded the IR spectrum of solution 3after 24h of ambient light illumination and compared it

with the spectrum of a freshly prepared 2.5%w/v P123ethanolic solution (solution 1).There was no indication of P123being oxidized since the two spectra were virtually identical (Figure 3).We used a relatively large amount of P123in our process (with a molar ratio of triblock copolymer to [Ag(NH 3)2]+ions of ~4).To rule out the possibility that a strong IR absorption from a high concentration of the triblock copolymer backbone may mask the signal from the oxidized surfactant,we repeated the IR measurements with a 25-fold diluted solution (i.e.,0.1%w/v P123ethanolic solution).Similar results were

(19)Longenberger,L.;Mills,G.

J.Phys.Chem.1995,99,475.(20)Liz-Marzan,L.M.;Lado-Tourino,https://www.wendangku.net/doc/6a1303184.html,ngmuir 1996,12,3585.(21)Zhang,D.H.;Qi,L.M.;Ma,J.M.;Cheng,H.M.Chem.Mater.2001,13,2753.Figure 1.UV -vis absorption spectra of solution 2illuminated via ambient light for different times or aged in the dark.

Figure 2.UV -vis absorption spectra of 10-3M [Ag(NH 3)2]+ethanolic solution and solution 3illuminated via ambient light for different times.No significant changes can be detected in the absorption spectra of 10-3M [Ag(NH 3)2]+ethanolic solution without P123after illuminating under ambient light for over 24h.

10374Langmuir,Vol.19,No.24,2003Zhang et al.

obtained,confirming that the P123was not oxidized in our system.The P123is obviously a more stable surfactant than the PEO-type nonionic surfactants used by other researchers.This is supported by the fact that the reduction of [Ag(NH 3)2]+ions in the P123ethanolic solution can only proceed under ambient light illumination,while the reduction of Ag +ions in ethanol containing nonionic surfactants such as poly-(10)-oxyethylene oleyl ether (Brij97)or poly(ethylene glycols)takes place either under ambient light illumination or in the dark.19

TEM images (Figure 4)show the silver nanoparticles synthesized with different initial [Ag(NH 3)2]+concentra-tions.At low [Ag(NH 3)2]+concentrations,silver particles with a bimodal size distribution are obtained (Figure 4A).Both large ones,with a size of ~30nm,and small ones,with a size of ~5nm or less (inset of Figure 4A),are present.The large ones may be formed by agglomeration of the small ones.At high [Ag(NH 3)2]+concentrations,the resulting silver nanoparticles show a narrower size distribution in the range of 10-20nm (Figure 4B).The HRTEM image (inset of Figure 4B)of a silver nanoparticle indicates that silver nanoparticles synthesized in this study are highly crystallized.The lattice fringes with a spacing of 2.40?correspond to the (111h )planes of face-centered-cubic silver,confirming the formation of silver nanoparticles.

Although the resulting silver ethanolic colloid is not stable under ambient light illumination,it can be stored in the dark for at least 1month without precipitation.When ethanol was replaced by water,the resulting aqueous silver colloid could be stable for weeks even under ambient light illumination,much more stable than its ethanolic counterpart.Meanwhile,the formation of silver nanoparticles could not be observed when a 0.1M [Ag-(NH 3)2]+aqueous solution was added into a freshly prepared 2.5%w/v P123aqueous solution under ambient light illumination.These phenomena indicate that ethanol takes part in the formation of silver nanoparticles induced by the P123under ambient light illumination.

Possible Mechanism for the Formation of Silver Nanoparticles under Ambient Light Irradiation.Based on the observations and characterization results,we propose a possible mechanism to explain the formation of silver colloid in our system (Scheme 1).First,[Ag(NH 3)2]+ions are incorporated in the micelles of triblock copolymer and bound to the pseudocrown ether structures of PEO

Figure 3.Infrared spectra of solution 3illuminated via ambient light for 24h (A)and freshly prepared solution 1(B).After a 10-3M [Ag(NH 3)2]+ethanolic solution containing 0.1%(w/v)P123is exposed to ambient light for 24h,its IR spectrum is still virtually identical to that of solution 1.

Figure 4.TEM images of silver nanoparticles synthesized with different initial [Ag(NH 3)2]+concentrations.(A)C [Ag(NH 3)2]+)10-4M,illumination time )56h.Inset:a higher magnification image of the sample prepared at the conditions given for panel A;the inset shows the coexistence of particles with two different sizes.(B)C [Ag(NH 3)2]+)2.5×10-3M,illumination time )20min.Inset:high-resolution TEM image of a silver nanoparticle in the sample prepared at the conditions given for panel B.

Synthesis of Ag Nanoparticles under Ambient Light Langmuir,Vol.19,No.24,2003

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and/or PPO.19,22,23This process of incorporation and binding causes dramatic change to the UV -vis spectra as shown in Figure 2.As soon as [Ag(NH 3)2]+ions are added into the P123ethanolic solution,the absorbance below 500nm increases sharply and a new peak at 278nm appears.Ag(I)shows a pronounced tendency to exhibit linear 2-fold coordination.24We think that the interactions between ions and oxyethylene groups disrupt the bonds

of Ag -N.Ag 2O is thus formed in the presence of a small amount of hydroxide ions in the reaction system.25Hydroxide ions are crucial in the formation of Ag 2O and the subsequent reduction of [Ag(NH 3)2]+ions,as we found that silver colloid would not form when Ag +ions instead of [Ag(NH 3)2]+ions were used as the silver source (Figure 5),because there were no hydroxide ions in the solution.The Ag 2O produced must be in the colloid form since no precipitation is observed in the solutions.Ag 2O is a semiconductor with a narrow band gap of about 2.25eV.26

(22)Warshawsky,A.;Kalir,R.;Deshe,A.;Berkovitz,H.;Patchornik,

A.J.Am.Chem.Soc.1979,101,4249.

(23)Borgarllo,E.;Pelizzetti,E.;Lawless,D.;Serpone,N.;Meisel,D.J.Phys.Chem.1990,94,5048.

(24)Advanced Inorganic Chemistry ,5th ed.;Cotton,F.A.,Wilkinson,G.,Eds.;Wiley:New York,1988;p 941.

(25)Huang,Z.Y.;Mills,G.;Hajek,B.J.Phys.Chem.1993,97,11542.(26)Varkey,A.J.;Fort,A.F.Sol.Energy Mater.Sol.Cells 1993,29,253.

Figure 5.UV -vis absorption spectra of a 10-3M Ag +ethanolic solution containing 2.5%P123(solution 4)illuminated via ambient light for different times.

Scheme 1.Schematic Illustration of the Possible Formation Process of Silver Colloid via Ambient Light

Illumination

10376Langmuir,Vol.19,No.24,2003Zhang et al.

Upon illumination with ambient light,electrons are excited to the Ag 2O conduction band leaving behind positive holes in its valence band.The electrons attract and reduce [Ag(NH 3)2]+ions on the Ag 2O surface to produce metal silver atoms.This process is similar to the formation of metal silver during the conventional photographic process where silver halide is used as a semiconductor to capture incident light.17Silver clusters will then form through the agglomeration of silver atoms and [Ag(NH 3)2]+ions.The reduction of [Ag(NH 3)2]+ions and the following agglomeration in our system may proceed as follows:

Positive holes produced in reaction 1react with ethanol

molecules to form H +ions,which react with the alkaline Ag 2O support and dissolve the support.25Water molecules are more difficult to oxidize than ethanol molecules.This fact can easily explain why the formation of silver nanoparticles could not be observed when the [Ag(NH 3)2]+aqueous solution was added to the P123aqueous solution under ambient light illumination and can also explain why the stability of the resulting silver colloid in water is much higher than that in ethanol in our study.

As the Ag 2O is gone,the metal -semiconductor interac-tion ceases to exist,which results in a blue shift of the absorption band from 450to 400nm.25This blue shift is clearly shown in Figure 2.Reactions 2and 3are believed to be completed in several microseconds.27The additional agglomeration steps,however,require more time.The first one is

The Ag 42+cluster,the ligand-free analogue of {Ag 2-[Ag(NH 3)2]2}2+,possesses a peak at 275nm on the absorption spectra.28Therefore,we believe that the peak at 278nm can be attributed to the {Ag 2-[Ag(NH 3)2]2}2+cluster.The 278nm peak can be observed in the absorption spectra of the freshly prepared solutions 2and 3,indicating that reaction 4is also very fast under our experimental conditions.When the sample is illuminated by ambient light,this 278nm peak increases in the first 20min and then decreases.This peak can even be observed in the absorption spectra of solution 3aged in the dark for weeks,implying that the P123is very efficient in stabilizing the {Ag 2-[Ag(NH 3)2]2}2+cluster.According to the results of Ershov et al.,27the subsequent agglomeration steps may be as follows:

These produced silver clusters can easily enter the hydrophobic cores of PPO,where the metallic silver

nanoparticles form.The growth of the silver clusters is primarily attributed to the accelerated agglomeration of silver clusters.27Another factor to consider is the size-dependent redox potential of the reduction of silver ions in solution.

The redox potential of reaction 8is dependent on the number of Ag atoms (m )in the cluster.The potential is a negative value when m <10,but it increases rapidly with increasing m .29As the number of Ag atoms in the clusters increases,the redox potential of reaction 8would increase to the extent that the [Ag(NH 3)2]+ions on the silver clusters could be reduced directly by the ethanol molecules.27This factor also accounts for the growth of silver clusters and the formation of larger metallic silver nanoparticles.On the other hand,the P123molecules can stabilize {Ag 2-[Ag(NH 3)2]2}2+through complexation.This complexation inhibits the agglomeration of the silver clusters and thus prevents the uncontrolled growth of the metallic silver nanoparticles (Scheme 1).Finally,a stable metallic silver colloid forms under the protection of the P123.The P123plays multiple roles in the formation of the metallic silver colloid:to induce the reduction of [Ag-(NH 3)2]+ions by forming Ag 2O,to control the growth of silver nanoparticles through complexing with silver clusters,and to prevent the agglomeration of silver nanoparticles through steric hindrance.

Recently,it was reported that the ambient light present in an ordinary chemical laboratory was sufficiently strong to transform some spherical silver nanoparticles into small triangle nanoplates.30This is another example of the application of ambient light in silver nanomaterial syn-thesis and confirms the crucial role of ambient light in the formation of silver nanoparticles in our study.Although our proposed mechanism is subject to further confirmation through the capture of the intermediates such as Ag 2O and {Ag 2-[Ag(NH 3)2]2}2+,this cannot hinder the attractive application of this novel method.We have utilized this method to prepare silver-coated TiO 2materials with enhanced photocatalytic and bactericidal activities.Formation of Silver-Coated TiO 2Nanoparticles.Figure 6shows TEM and HRTEM images of the silver-coated TiO 2.When the reduction of [Ag(NH 3)2]+takes place in the presence of the TiO 2particles,silver nanoclusters approximately 2nm in size are highly dispersed on TiO 2without aggregation (Figure 6).The surfactant micelles and TiO 2nanoparticles may prevent the aggregation of silver clusters.Therefore,the sizes of the silver particles deposited on TiO 2are significantly smaller than those of silver particles in the ethanolic colloid without TiO 2supports.No “support-free”particles were found in the resulting silver-coated TiO 2,indicating that silver particles were strongly anchored to the TiO 2supports.An HRTEM image (inset of Figure 6)shows that the highly crystalline silver particle is in close contact with the titania support.This close contact is believed to favor the electron transfer between the silver and TiO 2.31

The chemical states of elements in the silver-coated TiO 2were checked by X-ray photoelectron spectroscopy.Figure 7shows the representative survey XPS spectra of the silver-coated TiO 2sample and high-resolution XPS spectra of Ag (inset).The Ag 3d 5/2peak appears at a binding energy of 368.0((0.2)eV,whereas the splitting of the 3d

(27)Ershov,B.G.;Janata,E.;Henglein,

A.J.Phys.Chem.1993,97,339.

(28)Linnert,T.;Mulvaney,P.;Henglein,A.;Weller,H.J.Am.Chem.Soc.1990,112,4657.

(29)Henglein,A.Chem.Rev.1989,89,1861.

(30)Sun,Y.G.;Mayers,B.;Xia,Y.N.Nano Lett.2003,3,675.(31)Claus,P.;Hofmeister,H.J.Phys.Chem.B 1999,103,2766.

Ag 2O 98h ν

hole ++e -(1)[Ag(NH 3)2]++e -f Ag 0+2NH 3(2)Ag 0+[Ag(NH 3)2]+f Ag -[Ag(NH 3)2]+

(3)

2Ag -[Ag(NH 3)2]+f {Ag 2-[Ag(NH 3)2]2}2+

(4)

2{Ag 2-[Ag(NH 3)2]2}2+f

{Ag 4-[Ag(NH 3)2]3}3++[Ag(NH 3)2]+(5)

Ag m ++e -f Ag m

(8)

Synthesis of Ag Nanoparticles under Ambient Light Langmuir,Vol.19,No.24,200310377

doublet is at 6.0eV.This binding energy indicates that silver in the silver-coated TiO 2is of metallic nature.32Table 1summarizes the atomic ratios of Ag/Ti in the initial [Ag-(NH 3)2]+-TiO 2ethanolic suspensions and the final silver-coated TiO 2materials measured by XPS.The atomic ratios of Ag/Ti in the final silver-coated TiO 2materials are lower than the initial ones in the [Ag(NH 3)2]+-TiO 2ethanolic suspensions,indicating that 1h of ambient light il-lumination may not be enough for the reduction of all [Ag(NH 3)2]+ions.Also,the recovery yield of silver metal increases with the increase in the [Ag(NH 3)2]+concentra-tion of the initial ethanolic suspensions (Table 1).

A broad band at 480nm,which is attributed to the surface plasmon resonance of metallic silver nanopar-ticles,33appears on the UV -vis absorption spectra of silver-coated TiO 2(Figure 8).No peaks corresponding to silver were observed in the XRD patterns (not shown).This is due to the tiny content of silver metal in the silver-coated TiO 2materials.It is also found that such low loading of silver does not significantly affect the microstructure of TiO 2,since the BET (Brunauer -Emmett -Teller)surface area of the silver-coated TiO 2is very close to that of the uncoated TiO 2(Table 1).Such similarities in physico-chemical properties of the silver-coated TiO 2and the uncoated TiO 2make it convenient to study the effect of silver nanocluster deposition on the photocatalytic and bactericidal performance of TiO 2.

Photocatalytic Activity Studies.We first checked the photocatalytic performance of the silver-coated TiO 2prepared by this novel method and compared it with that of the uncoated TiO 2.It is found that the loading of silver can enhance the photocatalytic activity of TiO 2in the degradation of acetone in air (Figure 9).With the increase in the Ag/Ti molar ratio in the silver-coated TiO 2,this activity enhancement improves.It reaches a maximum value at an Ag/Ti molar ratio of 1.17×10-3.The enhanced photocatalytic activities of the silver-coated TiO 2can be

(32)Stathatos,E.;Lianos,P.

Langmuir 2000,16,2398.

(33)He,J.H.;Ichinose,I.;Fujikawa,S.;Kunitake,T.;Nakao,https://www.wendangku.net/doc/6a1303184.html,mun.2002,1910.

Figure 6.TEM (A)and HRTEM (B)images of AT-0.5.

Figure 7.Survey XPS spectra and high-resolution XPS spectra (inset)of AT-0.5.

Table 1.Summary of the Physicochemical Properties of

Silver-Coated TiO 2molar ratio of Ag/Ti materials initial a final b yield c %BET surface area (S BET )d (m 2/g)

AT-0.252×10-3 5.07×10-425.456.6AT-0.54×10-3 1.17×10-329.352.9AT-18×10-3

5.55×10-3

69.4

51.4P25

54.7

a

The initial molar ratio of Ag/Ti in the ethanolic TiO 2suspen-sions.b The final molar ratio of Ag/Ti in the silver-coated TiO 2measured by XPS.c The recovery yield as calculated through the final molar ratio of Ag/Ti in the silver-coated TiO 2divided by the initial molar ratio of Ag/Ti in the ethanolic TiO 2suspensions.d BET surface area calculated from the linear part of the BET plots.

Figure 8.UV -vis absorption spectra of the silver-coated TiO 2and the uncoated TiO 2(P25).

10378Langmuir,Vol.19,No.24,2003Zhang et al.

explained by better charge separation arising from the loading of silver nanoclusters.When silver nanoclusters are deposited on the TiO 2particles,electronic interactions occur between silver and TiO 2.Since the work function of silver is higher than that of TiO 2,photoexcited electrons transfer from the conduction band of the TiO 2particles to the vicinity of the silver clusters.This results in the formation of Schottky barriers at each silver -TiO 2contact region,thus promoting charge separation.10This electron transfer would inhibit the recombination of electron -hole pairs,leaving holes in the valence band of TiO 2.These holes can directly oxidize the organics or react with surface-adsorbed water and hydroxyl groups to produce hydroxyl radicals,which are powerful oxidants in degrading organics.34Our results also indicate that there is an optimum loading level of silver clusters.This is not surprising as excess silver islands may also act as the centers for the recombination of electron -hole pairs.14,15

Bactericidal Activity Study.Ag ions show bacteri-cidal effects.The World Health Organization (WHO)declared that silver does not cause adverse health effects and set a secondary minimum concentration level (MCL)of 90μg/L.Therefore,loading the biocompatible TiO 2with a tiny amount of silver is thought to increase the effectiveness of silver in terms of its economic importance and reusability,thus attracting more and more attention.35Meanwhile,the bactericidal effect of TiO 2under UV irradiation is well documented.36In this study,we also examined the bactericidal effects of the silver-coated TiO 2prepared in this study on M.lylae in water under UV irradiation in comparison with uncoated TiO 2.

M.lylae is a long wavelength UV resistant bacterial strain.No cell damage is observed after illumination under 365-nm UV for 1h.In the dark,neither 0.1mg/mL of the silver-coated TiO 2nor the uncoated TiO 2shows any bactericidal effect on M.lylae at a cell concentration of 3×106cfu/mL.This indicates that Ag +or Ag is not released from the silver-coated TiO 2to trigger a bactericidal response.However,after UV irradiation for 1h,the killing

percentages of M.lylae are 85%,69%,and 67%in the presence of 0.1mg/mL AT-0.5,AT-0.25,and P25,respec-tively (Figure 9).This reveals that the silver-coated TiO 2is a more effective antibacterial material than uncoated TiO 2under UV irradiation.In a separate experiment,an inductively coupled plasma atomic emission spectrometer (ICP-AES)was used to determine if Ag +or Ag could be

(34)Turchi,C.S.;Ollis,D.F.

J.Catal.1990,122,178.(35)So ¨kmen,M.;Candan,F.;Su ¨mer,Z.J.Photochem.Photobiol.,A 2001,143,241.

(36)Wei,C.;Lin,W.Y.;Zainal,Z.;Williams,N.E.;Zhu,K.;Kruzic,A.P.;Smith,R.L.;Rajeshwar,K.Environ.Sci.Technol.1994,28,934.Sunada,K.;Kikuchi,Y.;Hashimoto,K.;Fujishima,A.Environ.Sci.Technol.1998,32,726.Maness,P.C.;Smolinski,S.;Blake,D.M.;Huang,Z.;Wolfrum,E.J.;Jacoby,W.A.Appl.Environ.Microbiol.1999,65,4094.Yu,J.C.;Tang,H.Y.;Yu,J.G.;Chan,H.C.;Zhang,L.Z.;Xie,Y.D.;Wang,H.;Wong,S.P.J.Photochem.Photobiol.,A 2002,153,211.Ame ′zaga-Madrid,P.;Silveyra-Morales,R.;Co ′rdoba-Fierro,L.;Neva ′rez-Moorillo ′n,G.V.;Miki-Yoshida,M.;Orrantia-Borunda,E.;Sol?′s,F.J.J.Photochem.Photobiol.,B 2003,70,45.

Figure 9.Photocatalytic and bactericidal activities of the silver-coated TiO 2and the uncoated TiO 2(P25).

Figure 10.TEM images of M.lylae with 0.2mg/mL AT-0.5

at different stages of bactericidal experiments:(A)0min,(B)30min,and (C)60min.

Synthesis of Ag Nanoparticles under Ambient Light Langmuir,Vol.19,No.24,200310379

released from the catalyst.First,a0.1mg/mL silver-coated TiO2aqueous suspension was prepared.Then the powder was removed by centrifugation,and the solution was analyzed by ICP-AES.It was found that the Ag content in the solution was below the detection limitation of Ag (<3μg/L).This is much lower than the value of MCL of silver,and it further rules out the possibility of any released Ag+or Ag having a bactericidal effect.This also confirms that silver clusters are strongly anchored to the TiO2supports.

It was reported that the photocatalyst would not attack the cells directly,as they were protected by an outer peptidoglycan layer.37Therefore,the oxidizing species such as superoxide radicals and hydroxyl radicals are believed to be responsible for the killing of M.lylae under UV irradiation.In the presence of O2,the superoxide radicals and hydroxyl radicals are formed in the following reactions:38

To understand the bactericidal mechanism of these oxidizing species,the morphology of M.lylae at different stages during bactericidal experiments was checked by TEM study(Figure10).Figure10A confirms that TiO2 particles cannot enter into the cell but stay outside of the cell wall.After30min of irradiation,morphological changes were observed in some cells(Figure10B).Some electron-translucent portions appeared,but a destruction of the cell wall was not observed.After60min of irradiation,the hollow regions were extended and the morphological changes appeared in most of the cells (Figure10C),indicating the killing of M.lylae.These TEM images indicate that cell death is not due to the disruption of the cell wall,confirming that the killing of M.lylae is due to the oxidizing radicals generated by the TiO2 particles under UV irradiation.Therefore,the possible bactericidal process can be proposed as follows.The plasma membrane was first attacked by the oxidizing radicals through penetrating the outer layer of the bacteria.These reactive radicals oxidized coenzyme A and the membranes. The oxidation of coenzyme A inhibited cell respiration and directly caused cell death.39Meanwhile,the oxidation of the membrane broke the main permeability barrier of the bacteria.This resulted in the slow leakage of the intracellular materials including RNA,protein,and minerals,corresponding to the loss of cell viability at an early stage of the bactericidal experiment and the ap-pearance of the electron-translucent regions after30min of UV irradiation(Figure10B),leading to the subsequent death of M.lylae.37

Both photocatalytic and bactericidal activities of AT-0.5are~20%higher than those of the uncoated TiO2(P25). This fact reveals that the same oxidizing radicals may be responsible for the degradation of acetone and the killing of M.lylae during these two different processes,and better charge separation arising from the loading of silver nanoclusters is the reason for the activity enhancement.

Conclusions

A novel method has been developed to prepare silver nanoparticles by a triblock copolymer induced reduction of[Ag(NH3)2]+ions under ambient light illumination.A possible mechanism is proposed to explain the formation of silver nanoparticles.This method has successfully been applied to the preparation of silver-coated TiO2.This novel process does not require the use of reducing agents,UV irradiation,or an energy-consuming thermal treatment process,thus avoiding the sintering and/or aggregation of silver nanoparticles seen in conventional methods for the synthesis of silver-coated TiO2.The resulting silver-coated TiO2material with optimal silver loading shows enhanced photocatalytic and bactericidal activities com-pared to uncoated TiO2.

Acknowledgment.The work described in this paper was partially supported by a grant from the National Natural Science Foundation of China and the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.N-CUHK433/00).

LA035330M

(37)Saito,T.;Iwase,T.;Horie,J.;Morioka,T.J.Photochem. Photobiol.,B1992,14,369.

(38)Yamashita,H.;Honda,M.;Harada,M.;Ichihashi,Y.;Anpo,M.; Hirao,T.;Itoh,N.;Iwamoto,N.J.Phys.Chem.B1998,102,10707.

(39)Huang,Z.;Maness,P.C.;Blake,D.M.;Wolfrum,E.J.;Smolinski, S.L.;Jacoby,W.A.J.Photochem.Photobiol.,A2000,130,163.

TiO

2

f h++e-(9)

e-+O

2

f O2-(10)

O

2-+2H++e-f H

2

O

2

(11)

H

2O

2

+O

2

-f?OH+OH-+O

2

(12)

h++H

2

O f?OH+H+(13)

10380Langmuir,Vol.19,No.24,2003Zhang et al.

AE抠像实用插件PrimatteKeyer详细教程

AE抠像实用插件PrimatteKeyer详细教程 2010年08月06日 08:54 Primatte Keyer是Puttin Designs公司发行的插件,Primatte Keyer抠像插件提供了强大的用于高质量图像合成的超精度型板控制功能,Primatte软件是独立于解析度的,而且支持视频HDTV 甚至是电影图像,此插件具有: 1.独一无二的计算抠像(键)值的方法。 2.在图像柔和抠像部分的高级颜色处理 3.干净和精确的蓝色溢出排除功能。 4.以及简单的参数设置和操作方法。 下面我简单介绍一下Primatte Keyer控制界面。 下面就《鹤舞》形象片中的Primatte Keyer插件的应用与大家共同探讨。

1.选择抠蓝舞者的图层,执行命令Effectlputtin primattekeyerlprimatte keyer,从我们实拍的抠像素材中可以看出蓝背景中的蓝色不均,而且还有结缝、布褶,如图1。 2.用鼠标激活Auto setup自动抠像钮之后,使用鼠标右键在合成影响窗口的蓝色区域点一下,采集蓝色标本.结果如图2,此采集可以采集一点,也可以采集多个点(Alt 鼠标左键移动)。 3.单击遮片按钮观看遮片,在遮片较暗的区域中相当多灰的布纹与斑点。如图3。 4.为了除去这样的斑点,单击Select BG 按钮.然后在某些噪音区域采样,如果一个采样不够只须持续采样,直到背景区域变成纯黑色,如图

4.为了除去这样的斑点,单击Select BG按钮.然后在某些噪音区域采样,如果一个采样不够只须持续采样,直到背景区域变成纯黑色,如图4。 5.当我们看遮片时,会发现白色遮片中有一些小黑点,单击Select FG,按钮然后在小黑点区域进行采样,一直到前景呈现纯白色。 6.无论SelectBG或是Select FG按钮进行采样时,舞者右下角的布褶是抠不下去的,采样数值过大时,会发现虽然布褶下去了,但头发丝也已经没有了,为此我们采用FineTuning按钮,进行精细调整,在保持飘动头发丝的细节不变的情况下,尽量使布褶透明下去,如图5。 7.然后我们用AE的遮罩功能。点击Effect/Layer/new mask用遮罩把布褶遮下去,给mask的Feather输入一定的羽化值,这样边界比较柔和,如图6。 8.在以上处理过程中,去除溢出色可能产生染色,这样抠像得到的景象可能偏色,所染的颜色,取决于被抠像的原始颜色一一

AE中抠像的常用方法

AE中抠像的常用方法 (1)如果素材图像主要为蓝背景,首先用某种色键(如Color Difference Key 颜色差值键),建一个橙色固态层作为参考背景,通过遮罩视图(Matte View)调整键控范围,包括透明、半透明和不透明的区域.再使用Spill Suppressor 溢出控制器,消除键控色留下的痕迹; Alpha Level 调整Alpha 通道的透明程度:Matte Choker 遮罩堵塞工具凋整遮罩中的空洞. 调整到满意后,在合成图像中,将固态层替换为新的背景素材。最后,根据素材变化,调整键控及遮罩参数,并设置关键帧,完成作品。 (2)对在蓝色或绿色背景中具有平稳亮度的素材键控的方法: 首先可以用Color Difference Key 颜色差值键控,再用Spill Suppressor溢出控制器,清除键控色的痕迹。如果要求更高,还可以使用Simple Choker 简单堵塞工具和Matte Choker 遮罩堵塞工具进行精细调整。如果结果还不满意,暂时关闭Color Difference Key , 重新使用Linear Color Key 线性色键。 (3)对在蓝色或绿色背景中包含有多种颜色或亮度不稳定的素材

键挖的方法: 首先应用Color Range 颜色范围键控,再用Spill Suppressor 溢出控制器和其它遮罩工具。 如果结果不满意,重新使用或加入Linear Color Key 线性色键。 (4)在黑暗和阴影的区域产生透明的方法: 先用Extract 抽取键控,设置为Luminance Channel 亮度通道。 (5)对固定背景(可以是复杂背景)应用键控的方法: 首先用Difference Matte 差值遮罩键控,以单独的背景图层作为遮罩参考,进行差值。 再加入Spill Suppressor 溢出控制器和其它遮罩工具。对于不同的实际情况,选择适当的键控方法,以得到满意的效果。对复杂的键控处理,可能要用到不同的键控才能得到满意的结果,可以组合两个或者更多的键控和遮罩。 通过效果开关应用或不应用效果,观察键控效果。

AE内置特效中英文对照

Distort扭曲特效 --Bezier warp贝赛尔曲线弯曲 --Bulge凹凸镜 --CC Bend It 区域卷曲效果 --CC Bender 层卷曲效果 --CC Blobbylize 融化效果 --CC Flo Motion 两点收缩变形 --CC Griddler 网格状变形 --CC Lens 鱼眼镜头效果,不如Pan Lens Flare Pro --CC Page Turn 卷页效果 --CC Power Pin 带有透视效果的四角扯动工具,类似Distort/CornerPin --CC Ripple Pulse 扩散波纹变形,必需打关键帧才有效果 --CC Slant 倾斜变形 --CC Smear 涂抹变形 --CC Split 简单的胀裂效果 --CC Split 2 不对称的胀裂效果 --CC Tiler 简便的电视墙效果 --Corner pin边角定位 --Displacement map置换这招 --Liquify像素溶解变换 --Magnify像素无损放大 --Mesh warp液态变形 --Mirror镜像 --Offset位移 --Optics compensation镜头变形 --Polar coordinates极坐标转换 --Puppet木偶工具 --Reshape形容 --Ripple波纹 --Smear涂抹 --Spherize球面化 --Transform变换 --Turbulent displace变形置换 --Twirl扭转 --Warp歪曲边框

--Wave warp波浪变形 Expression Controls表达式控制特效 --Angel control角度控制 --Aheckbox control检验盒控制 --Color control色彩控制 --Layer control层控制 --Point control点控制 --Slider control游标控制 Generate 渲染 --4-ccolor gradient四角渐变 --Advanced lightning高级闪电 --Audio spectrum声谱 --Audio waveform声波 --Beam光束 --CC Glue Gun 喷胶效果 --CC Light Burst 2.5 光线缩放 --CC Light Rays 光芒放射,加有变形效果--CC Light Sweep 过光效果 --Cell pattern单元图案 --Checkerboard棋盘格式 --Circle圆环 --Ellipse椭圆 --Eyedropper fill滴管填充 --Fill 填充 --Fractal万花筒 --Grid网格 --Lens flare镜头光晕 --Paint bucker颜料桶 --Radio waves电波 --Ramp渐变 --Scribble涂抹 --Stroke描边 --Vegas勾画 --Write-on手写效果

AE抠像教程

AE抠像教程 “抠像”即“键控技术”在影视制作领域是被广泛采用的技术手段,实现方法也普遍被人们知道一些――当您看到演员在绿色或蓝色构成的背景前表演,但这些背景在最终的影片中是见不到的,就是运用了键控技术,用其它背景画面替换了蓝色或绿色,这就是“抠像”。 当然,“抠像”并不是只能用蓝或绿,只要是单一的、比较纯的颜色就可以,但是与演员的服装、皮肤的颜色反差越大越好,这样键控比较容易实现。如果是实时的“抠像”都需要视频切换台或者支持实时色键的视频捕获卡。但价格比较昂贵,个人基本上是承受不了的。在After Effects中,实现键控的工具都在特技效果中,标准版的After Effects 5.5内置的特效只包括Color Key色键和Luma Key亮键:完整版After Effects 5.5 Production Bandle包含了 Color Difference Key颜色差值键、 LinerColor Key线性色键, Difference Matte差值遮罩、 Color Range颜色范围键控、 Extract抽取键控。 1,应用Color Key 对于单一的背景颜色,可称为键控色。当选择了一个键控色(即吸管吸取的颜色〕,应用Color Key,被选颜色部分变为透明。同时可以控制键控色的相似程度.调整透明的效果。还可以对健控的边缘进行羽化,消除“毛边”的区域。 具体使用Color Key色键的方法:举个小例子,使用一张白色背景的蝴蝶图片和一张黑背景的花朵图片,抠去蝴蝶图片的白色背景,使其看上去好像落在花上。首先选择要应用色键的层。――-在例子中我选择白色背景的蝴蝶图片。再给其加上Color Key特效(菜单Effect>Keying>Color Key),应用Color Key 色键。其次,效果控制窗口中,单击小吸管,鼠标箭头变成吸管状,然后在蝴蝶图片的白色区域单击一下,(或者点击颜色方块,弹出“颜色”对话框,用HSL或RGB方式指定一个颜色)。击“吸管”按钮,在层窗口或合成窗口中选择颜色,如图--单击后,我们看到白色区域消失了,但蝴蝶边缘还有白色的锯齿毛边。这时需要调整以下参数: Color Tolerance用于控制颜色容差范围。值越小,颜色范围越小。 Edge Thin 用于调整键控边缘,正值扩大遮罩范围,负值缩小遮罩范围。 Edge Fether用于羽化键控边缘,产生细腻、稳定的键控遮罩。 2,使用Color Range颜色范围键控 Color Range颜色范围键控通过键出指定的颜色范围产生透明,可以应用的色彩空间包括Lab、YUV和RGB。这种键控方式,可以应用在背景包含多个颜色、背景亮度不均匀和包含相同颜色的阴影(如玻璃、烟雾等),遮罩视图用于显示遮罩情况的略图。 键控滴管用于在遮罩视图选择开始的键控色。 加滴管增加键控色的颜色范围。 减滴管减少键控色的颜色范围。 Fuziness 用于调整边缘柔化度、 Color Space选择颜色空间,有 Lab、YUV和RGB可供选择。 Min/Max精确凋整颜色空间参数L,Y,R、a,U,G和b,V,B代表颜色空间的三个分量。Min**调整颜色范围开始,Max**调整颜色范围结束。 3,使用Difference Matte差值遮罩 Difference Matte差值遮罩通过比较两层画面,键出相应的位置和颜色相同的像素。最典型的应用是静态背景、固定摄像机、固定镜头和曝光,只需要一帧背景素材,然后让对象在场景中移动,效果控制参数如图: View可以切换预览窗口和合成窗口的视图,选择Final Output最终输出结果、Source Only显示源素材和Matte Only显示遮罩视图。Difference Layer选择用于比较的差值层,None表示没有层列表中的某一层。If Layer Sizes Differ用于当两层尺寸不同的时候。可以选择Center将差值层放在源层中间比较,其它的地方用黑色填充:Stretch to Fit伸缩差值层,使两层尺寸一致,不过有可能使背景图像变形。Matching

AE影视合成中常用的技术

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Color correction 颜色校正 --auto color自动色彩调整 --auto contrast自动对比度 --auto levels自动色阶 --brightness & contrast亮度核对比度 --broadcast colors播放色 --change color转换色彩 --change to color颜色替换 --channel mixer通道混合 --color balance色彩平衡 --color blance(HIS)色彩平衡(HIS) --color link色彩连接 --color stabilizer色彩平衡器 --colorama彩光 --curves曲线调整 --equalize均衡效果 --exposure多次曝光 --gamma/pedestal/gain伽马/基色/增益 --hue/saturation色相/饱和度 --leave color退色 --levels (individual controls)色阶(个体控制) --photo filter照片过滤 --PS arbitrary Map映像遮罩 --shadow/highlight阴影/高光 --tint 浅色调/色度 --tritone三阶色调整 Distort扭曲特效 --bezier warp贝赛尔曲线弯曲 --bulge凹凸镜 --corner pin边角定位 --displacement map置换这招 --liquify像素溶解变换 --magnify像素无损放大 --mesh warp液态变形

AE自带特效中英文对照表

AE自带特效中英文对照表 2012-06-03 14:04:40| 分类:默认分类|举报|字号订阅3D Channel三维通道特效 --3d chanel extract 提取三维通道 --depth matte深度蒙版 --depth of field场深度 --fog 3D雾化 --ID Matte ID蒙版 Blur & Sharpen模糊与锐化特效 --box blur方块模糊 --channel blur通道模糊 --compound blur混合模糊 --directional blur方向模糊 --fast blur快速模糊 --gaussuan blur高斯模糊 --lens blur镜头虚化模糊 --radial blur径向模糊 --reduce interlace flicker降低交错闪烁 --sharpen锐化 --smart blur智能模糊 --unshart mask反遮罩锐化 Channel通道特效 --alpha levels Alpha色阶 --arithmetic通道运算 --blend混合 --calculations融合计算 --channel combiner复合计算 --invert反相 --minimax扩亮扩暗 --remove color matting删除蒙版颜色 --set channels设置通道 --set matte设置蒙版 --shift channels转换通道 --solid composite实体色融合

Color correction 颜色校正 --auto color自动色彩调整 --auto contrast自动对比度 --auto levels自动色阶 --brightness & contrast亮度核对比度 --broadcast colors播放色 --change color转换色彩 --change to color颜色替换 --channel mixer通道混合 --color balance色彩平衡 --color blance(HIS)色彩平衡(HIS) --color link色彩连接 --color stabilizer色彩平衡器 --colorama彩光 --curves曲线调整 --equalize均衡效果 --exposure多次曝光 --gamma/pedestal/gain伽马/基色/增益 --hue/saturation色相/饱和度 --leave color退色 --levels (individual controls)色阶(个体控制) --photo filter照片过滤 --PS arbitrary Map映像遮罩 --shadow/highlight阴影/高光 --tint 浅色调/色度 --tritone三阶色调整 Distort扭曲特效 --bezier warp贝赛尔曲线弯曲 --bulge凹凸镜 --corner pin边角定位 --displacement map置换这招 --liquify像素溶解变换 --magnify像素无损放大 --mesh warp液态变形 --mirror镜像 --offset位移

关于AE抠像的基本原理说明

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AE自带特效中英文对照表

AE自带特效中英文对照表3D Channel三维通道特效 3d channel extract 提取三维通道 depth matte深度蒙版 depth of field场深度 fog 3D雾化 ID Matte ID蒙版 Blur & Sharpen模糊与锐化特效 box blur方块模糊 channel blur通道模糊 compound blur混合模糊 directional blur方向模糊 fast blur快速模糊 gaussian blur高斯模糊 lens blur镜头虚化模糊 radial blur径向模糊 reduce interlace flicker降低交错闪烁 sharpen锐化 smart blur智能模糊 unsharp mask反遮罩锐化 Channel通道特效 alpha levels Alpha色阶

arithmetic通道运算 blend混合 calculations融合计算 channel combiner复合计算 invert反相 minimax扩亮扩暗remove color matting删除蒙版颜色set channels设置通道 set matte设置蒙版 shift channels转换通道 solid composite实体色融合 Color correction 颜色校正 auto color自动色彩调整 auto contrast自动对比度 auto levels自动色阶brightness & contrast亮度核对比度broadcast colors播放色 change color转换色彩 change to color颜色替换 channel mixer通道混合 color balance色彩平衡 color blance(HIS)色彩平衡(HIS)

AE自带特效中文英对照

3D Channel三维通道特效 --3D chanel extract 提取三维通道 --Depth matte 深度蒙版 --Depth of field 场深度 --ExtractoR 提取器 --Fog 3D 3D 雾化 --ID Matte ID蒙版 --Identifier 标识符 Audio 音频特效 --Backwards 倒播 --Bass & treble 低音和高音 --Delay 延迟 --Flange & chorus 变调和合声 --High-low pass 高低音过滤 --Modulator 调节器 --Parametric EQ EQ 参数 --Reverb 回声 --Stero mixer 立体声混合 --Tone 音质 Keying 抠像特效 --CC Simple Wire Removal 简单的去除钢丝工具,实际上是一种线状的模糊和替换效果 --Color difference key 色彩差抠像 --Color key 色彩抠像 --Color range 色彩范围 --Difference matte 差异蒙版 --Extract 提取 --Inner/outer key 轮廓抠像 --Keylight(1.2) --Linear color key 线性色彩抠像 --Luma key 亮度抠像 --Spill suppressor 溢色抑制

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(3):但我们可以发现图像有明显的噪点,在matee模式下我们可以看见噪点。选择背景噪点清除工具在白色的噪点上来回的划及下,请注意不要把头发等细节也划进去了。

(4):同理如果白色的前景上有黑灰色的噪点时,我们就需要用前景噪点清除工具在白色的前景上把噪点“划”掉,呵呵!这世界清静了!

(5):接下来我们要精细调整一下,以得到更好的效果。在合成模式下选择调整工具,然后按住鼠标在你想要调整地方划几下,我们就会发现溢出,透明和细节三项划杆会自动调节,而画面的效果变得更加理想。

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