Z-scheme transfer pathway assisted photoelectrocatalyst Zn2SnO4/rGO/Ag/AgBr for organic pollutants treatment

Abstract

Rational design of photoelectrode with high visible light utilization rate and separation efficiency of electron-hole pairs is the key step in photoelectrocatalytic technology. In this work, Z-Scheme photoelectrocatalyst (ZTO/rGO/Ag/AgBr) was synthesized by hydrothermal and photo-reduction process. Comparing with pure Zn2SnO4 (ZTO), adding reduced graphene oxide (rGO) effectively improved electrons transfer efficiency. Notably, the addition of Ag/AgBr not only broaden the visible light response range of ZTO, but also accelerated the separation of photo-generated electron-hole pairs, and constructed all-solid-state Z-Scheme heterojunction. Meanwhile, DFT calculation showed that Ag metal on rGO surface could act as active site for organic dyes degradation. Moreover, the addition of extra bias potential during photoelectrochemical process not only accelerate the migration of carriers, but also inhibit the recombination of photo-generated electron-hole pairs. Methylene blue (MB) could be effectively removed during photoelectrochemical reaction process, which was attributed to hydroxyl radical (•OH) and superoxide radical (•O2-). In this work, Z-Scheme transfer pathway, assisted photoelectrocatalytic technology, is a feasible strategy for improving catalytic performance.