AgBr/g-C_(3)N_(4)复合光催化剂制备及其可见光催化性能

Preparation of AgBr/g-C_(3)N_(4) Composite Photocatalyst and Its Visible Light Catalytic Performance

文章采用溶剂热法合成不同形貌和结构的g-C_(3)N_(4)半导体,超声法将AgBr原位沉淀在g-C_(3)N_(4)表面,成功制备出不同质量比AgBr/g-C_(3)N_(4)复合光催化剂。借助FE-SEM、BET、TGA、XRD、UV-Vis DRS等方法对制备样品的晶体结构、形貌、比表面积、热稳定性以及其光学性能进行了表征。结果表明:g-C_(3)N_(4)半导体呈现纳米管状结构,直径约为300 nm,管长约为800 nm;AgBr/g-C_(3)N_(4)-20%复合光催化剂比表面积可达为40.727 m^(2)/g,孔体积0.110 cm^(3)/g,孔半径为17.171 nm。以罗丹明B(RhB)为模拟污染物,考察光催化降解性能,结果表明AgBr/g-C_(3)N_(4)质量比为20%时,可见光催化80 min后,RhB降解率可达到97.4%。光催化机理研究表明,空穴(h+)是光催化降解RhB的主要活性物种,其次为超氧自由基(·O_(2)-)与羟基自由基(·OH),根据能带理论推测AgBr/g-C_(3)N_(4)符合Z型电荷转移机制。

g-C_(3)N_(4) semiconductors with different morphologies and structures were synthesized by solvothermal method.AgBr was in-situ precipitated on the surface of g-C_(3)N_(4) by ultrasonic method,and AgBr/g-C_(3)N_(4) composite photocatalysts with different mass ratios were successfully prepared.The crystal structure,morphology,specific surface area,thermal stability and optical properties of the samples were characterized by FE-SEM,BET,TGA,XRD and UV-Vis DRS.The results show that the g-C_(3)N_(4) semiconductor has a tubular nanorod structure with a diameter of about 300 nm and a length of about 800 nm.The specific surface area,pore volume and pore radius of AgBr/g-C_(3)N_(4)-20%composite photocatalyst were 40.727 m^(2)/g,0.110 cm^(3)/g and 17.171 nm,respectively.Rhodamine B(RhB)was used as the simulated pollutant to investigate the photocatalytic degradation performance.The results showed that when the mass ratio of AgBr/g-C_(3)N_(4) was 20%,the degradation rate of RhB could reach 97.4%after 80 min.The study of photocatalytic mechanism showed that hole(h+)was the main active species,followed by superoxide radical(·O_(2)-)and hydroxyl radical(·OH).