Photocatalysis uranium (VI) reduction at Cu2O/WO3|FTO Z-scheme heterojunction systems

Abstract

A two-step method was used to synthesize Cu2O/WO3 composites with Z-scheme electron transfer on the surface of FTO, which were then utilized for the photocatalytic reduction of U(VI). At pH = 6, the U(VI) photocatalytic reduction achieves a removal ratio of 98.3% and a first order rate constant rate of 0.0216 min−1. In 10 cycles, the Cu2O/WO3|FTO photocatalytic reduction of U(VI) maintained a 95.01% efficiency. The four stages of photocatalytic uranium reduction are calculated and described by DFT. (1) Cu2O/WO3|FTO competes with uranium clusters. (2) Adsorption is completed by the active site of Cu2O/WO3|FTO. (3) Cu2O/WO3|FTO-[UO2(OH)2]·2 H2O produces photoelectron reduction U(VI) after exposure to light; (4) The generated U(IV) is detached from the adsorption site under the action of water flow.