Au/g-C_3N_4复合微粒的制备及光催化还原对硝基苯酚

Preparation of Au/g-C_3N_4 composite particles and photocatalytic reduction of p-nitrophenol

为了解决光生电子-空穴因分离难而对g-C_3N_4光催化活性造成影响的问题,采用原位法制备了Au/g-C_3N_4复合微粒,利用TEM,SEM,XRD,XPS和FTIR等测试方法对复合微粒的形貌、微观结构和组成进行表征,通过UV-vis DRS,PL和EIS等方法分析了复合微粒的光电性能,并以对硝基苯酚还原反应为模型,考察了Au/g-C_3N_4复合微粒的可见光催化性能。结果表明:g-C_3N_4为片层堆积结构的六方相晶体,片层间的纳米金为面心立方晶型;纳米金的引入显著提高了g-C_3N_4基体对可见光的吸收及其光生电子-空穴对的分离效率;当金含量为0.5%(质量分数)、氯金酸钠与柠檬酸钠物质的量比为1∶3时,光催化剂的活性最高。所制备的复合催化剂可见光响应性强,催化活性较纯g-C_3N_4明显提高,为合成g-C_3N_4基高效光催化剂提供了理论依据。

In order to solve the problem of photo-generated electron-hole separation which affects g-C3N4 photocatalytic activity,Au/g-C3N4 composite particles are in situ prepared.The morphology,microstructure and composition of as-prepared Au/g-C3N4 composite particles were characterized by TEM,SEM,XRD,XPS and FTIR,the photoelectric property of the composite particles is also characterized by UV-vis DRS,PL and EIS,and the catalytic activities were examined using the reduction of 4-NP as a model reaction.The results show that the laminated g-C3N4 is hexagonal crystal,while the gold nanoparticles dispersing between the lamella of the g-C3N4 are face-centered cubic crystallites.The visible-light absorption and electron-hole separation efficiency of g-C3N4 matrix are improved by the introduction of gold nanoparticles.When the mass fraction of Au is 0.5%,the amount of substance ratio of sodium chloroaurate and sodium citrate is 1∶3,the Au/g-C3N4 composite demonstrates the best photocatalytic activity.The composite catalyst has strong visible light responsiveness and significantlyhigher catalytic activity than pure g-C3N4,which provides a theoretical basis for the synthesis of g-C3N4 photocatalyst with high photocatalytic activity.