All-solid Z-scheme Bi/γ-Bi2O3/O-doped g-C3N4 heterojunction with Bi as electron shuttle for visible-light photocatalysis

In order to broaden the spectral response range of graphitic carbon nitride (g-C3N4) and improve its visible light catalytic activity, the method of ethanol-assisted solvo-thermal pretreatment and subsequent polymerization was used to prepare Bi/gamma-Bi2O3 nanoparticles modified O-doped g-C3N4 (Bi/gamma-Bi2O3/EtCN). During the polymerization of g-C3N4 , oxygen doping brought about a richer pore structure, while ethanol and urea promoted the formation of sub-stable gamma-Bi2O3, and most importantly, these reactions were achieved simultaneously to successfully fabricate the all-solid Z-scheme structure. The obtained Bi/gamma-Bi2O3/ EtCN showed much higher activity in the visible-light photocatalytic degradation of bisphenol A (BPA) than that of g-C3N4 and EtCN, where the degradation rate of 0.03Bi/gamma-Bi2O3/EtCN was 15.67 times higher than that of g-C3N4 , showing excellent visible photocatalytic performance. The improvement of the activity of Bi/gamma-Bi2O3/EtCN mainly caused by the formation of all-solid Z-scheme heterojunction between gamma-Bi2O3 and EtCN with Bi as the electron shuttle, which broadened the light absorption range of the catalyst, promoted the effective separation of electron-hole pairs. It was also found that center dot O-2(-) played a major role and h+ played a secondary role during BPA degradation process using 0.03Bi/gamma-Bi2O3/EtCN as the photocatalyst, which confirmed the mechanism of Z-scheme heterojunction. (c) 2022 Elsevier B.V. All rights reserved.