Preparation Of Silver/Conjugated Polymers Composites And Study On Their Photocatalytic Reduction Properties

An uniformly dispersed silver/carbon nitride nanohybrid stabilized by starch was synthesized using an efficient microwave-assisted synthetic method using vanillin as a reducing agent.The prepared materials were characterized by transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,X-ray diffraction（XRD）,Raman spectroscopy,fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,UV-vis diffuse reflection spectroscopy（UV-vis DRS）,photoluminescence spectroscopy（PL）,electrochemical impedance spectra（EIS）and photocurrent analysis.The results reveal that the silver nanoparticles in small amount do not change the chemical composition and crystalline of g-C₃N₄ significantly.But they are highly dispersed in the g-C₃N₄ sheets and improve the visible-light absorption and electron-hole separation efficiency of Ag/g-C₃N₄ nanohybrid obviously.The reduction of4-NP with NaBH₄ was chosen as a model reaction to examine the catalytic activities.The results show that when mass ratio of Ag and g-C₃N₄ is 1:20,the photocatalytic ability of Ag/g-C₃N₄ nanohybrid are the best.Ag/CPVC composite photocatalysts were prepared via an in situ ultraviolet light reduction synthesis method with polyvinyl chloride（PVC）and silver nitrate as the main raw materials and chitosan（CS）as protective agent.SEM,XRD,FTIR,XPS,UV-vis DRS,PL,EIS and photocurrent analysis were used to characterized the as-prepared Ag/CPVC composite.As a result,the silver particles were dispersed on the suface of CPVC evenly,and the structure of CPVC has little change with the introduction of silver particles.The synthesized silver particles are the face-centered cure crystalline and the average particle size is ca.26nm.The existence of silver nanoparticles improves the visible-light absorption and electron-hole separation efficiency of the CPVC obviously.The reduction of 4-NP with NaBH₄ was chosen as a model reaction to examine the catalytic activities.The results showed that when mass ratio of Ag and CPVC was 1:30,the ultraviolet light reduction time was 2 h,and the concentration of the protective agent was 0.3wt%,the photocatalytic ability of Ag/CPVC composite was the best.Au/g-C₃N₄ composite particles were prepared with an in situ synthesis method using sodium chloroaurate as the source of gold and sodium citrate as reduction agent.TEM,SEM,XRD,XPS,FTIR,UV-vis DRS,PL,EIS and photocurrent analysis were also used to characterized the as-prepared Au/g-C₃N₄ composite particles similar to Ag/g-C₃N₄.the gold nanoparticles were not change the chemical composition and crystalline of g-C₃N₄obviously as well,and the visible-light absorption and electron-hole separation efficiency of Au/g-C₃N₄ composite were improved by the introduction of gold nanoparticles.The catalytic activities were examined using the reduction of 4-NP as a model reaction.The results showed that when the Au mass fraction was 0.5wt%,the molar ratio of sodium chloroaurate and sodium citrate was 1:3,the Au/g-C₃N₄ composite demonstrated the best photocatalytic ability.