Facile synthesis of Z-scheme KBiO3/g-C3N4 Z-scheme heterojunction photocatalysts: Structure, performance, and mechanism

Abstract

The proper design of interfacial contact of heterojunction photocatalyst plays an important role in the transfer/separation of interfacial charge carriers. The Z-type photocatalyst can reduce the recombination of photogenerated electron-hole pairs and retain the original redox ability. Here, KBiO3/g-C3N4 Z-scheme heterojunction photocatalysts were facile synthesized by mixing and programmed heating. Compared to pure g-C3N4 and KBiO3, the photocatalytic performance of the obtained photocatalyst on the photo-oxidative degradation of crystal violet and phenol was improved significantly. The apparent rate constants of degrading CV (Crystal Violet) and phenol were 0.15493 min−1 and 0.02057 min−1, which were 10 times and 4 times that of pure KBiO3, respectively. The formation mechanism of KBiO3/C3N4 Z-type heterojunction was investigated by experiments and DFT calculations. The result shows that the improvement of photo-degradation performance was attributed to the internal electric field formed by the Z-scheme photo-catalyst, which leads to the enhancement of visible light absorption and the blocking effect of light-induced electron-hole recombination.