双缺陷调控的Z型BiVO_(4-x)/g-C3N_(4-x)异质结的制备及其光催化全解水

Preparation of Z-scheme BiVO_(4-x)/g-C3N_(4-x) heterojunction mediated by double defects and photocatalytic overall water splitting

为了获得高效的全解水光催化体系,采用固相烧结法和水热法制备了双缺陷调控的Z型BiVO_(4-x)/g-C3N_(4-x)异质结,对异质结的微观结构和光电特性进行了表征,测试了BiVO_(4-x)/g-C3N_(4-x)异质结的光催化全解水制氢、氧的性能。结果表明:丰富的氧空位和氮空位的引入、紧密连接的复合结构界面及直接Z型异质结的构筑,提高了材料对可见光的吸收,加快了光生电荷的分离和传输,从而导致材料具有高效的光催化活性。双缺陷调控的Z型BiVO_(4-x)/g-C_(3)N_(4-x)异质结具有优异的光催化活性和稳定性,在可见光照射下,不添加任何吸收剂析氢速率可达654μmol/(h·g),是g-CN前驱体的6.5倍,析氧速率可达302μmol/(h·g),经过20 h的长时间可见光照射,样品的光催化活性没有下降。

Z-scheme BiVO_(4-x)/g-C_(3)N_(4-x)heterostructure mediated by double defects were prepared by solid phase sintering and hydrothermal methods to acquire an efficient photocatalytic system for full water splitting. The microstructure and optoelectronic properties of the heterostructure were characterized, and the photocatalytic properties of BiVO_(4-x)/g-C_(3)N_(4-x)heterostructure for hydrogen and oxygen production by overall photocatalytic water splitting were tested. The results show that the introduction of abundant oxygen vacancy and nitrogen vacancy, the tightly connected interface and the construction of direct Z-scheme heterojunction improve the visible light absorption and accelerate the separation and transfer of photogenerated charge. As a result, the material has highly efficient photocatalytic activity. The Z-scheme BiVO_(4-x)/g-C_(3)N_(4-x)heterojunction mediated by double defects show excellent photocatalytic activity and stability. Under visible light irradiation, the hydrogen and oxygen evolution rate reach 654 μmol·h·g, which is 6.5 times as high as that of g-CNprecursor, and the oxygen evolution rate reach 302 μmol·h·g. After 20 h of visible light irradiation, the photocatalytic activity of the sample doesn’ t decrease.