Bi3+/Ag3PO4 photocatalyst with higher absorption of visible light and improved stability

Abstract

This work was devoted to the synthesis of new photocatalysts based on hydrothermal grafting of Bi 3+ at different percentages onto Ag 3 PO 4 synthesized by co-precipitation method. The catalysts were subjected to a sequence of characterization measurements by XRD, TEM, FESEM/EDX, HRTEM/EDX, FTIR, and UV–vis DRS. The photocatalytic performance was evaluated in the photocatalytic degradation of methyl orange (MO) under visible light irradiation. After grafting Bi 3+ to the surface of Ag 3 PO 4 (AgP), the activity was improved compared to bare AgP. The best activity was obtained by the catalyst with 2°% grafting (2°% Bi–AgP), and as the amount of Bi 3+ increased, the catalytic activity decreased. It was found that Bi 3+ grafting is better than Bi 3+ doping due to the independence of the discrete electronic levels of Bi 3+ from the continuous electronic levels of AgP. Under irradiation, the excited electrons are directly transferred to the vacant d orbitals of Bi 3+ , which is known as the interfacial charge transfer process. Electron trapping by Bi 3+ plays a key role in preventing charge recombination and prolonging their lifetime, thereby enhancing MO degradation activity. In addition, the stability of the photocatalyst was advantageously improved. • Bi 3+ /Ag 3 PO 4 photocatalysts were synthesized by co-precipitation/hydrothermal method. • The photocatalytic activity was tested for MO degradation under visible light. • 2°% Bi-grafted Ag 3 PO 4 showed the highest efficiency. • Bi 3+ traps electrons, reducing charge recombination.