Facile synthesis of Ag2O/ZnO/rGO heterojunction with enhanced photocatalytic activity under simulated solar light: Kinetics and mechanism

Peng Xu; Peng Wang; Qiao Wang; Rui Wei; Yang Li; Yanjun Xin; Tong Zheng; Limin Hu; Xiaojing Wang; Guangshan Zhang

doi:10.1016/j.jhazmat.2020.124011

Facile synthesis of Ag₂O/ZnO/rGO heterojunction with enhanced photocatalytic activity under simulated solar light: Kinetics and mechanism

J Hazard Mater. 2021 Feb 5:403:124011. doi: 10.1016/j.jhazmat.2020.124011. Epub 2020 Sep 18.

Authors

Peng Xu¹, Peng Wang², Qiao Wang², Rui Wei², Yang Li³, Yanjun Xin⁴, Tong Zheng², Limin Hu², Xiaojing Wang², Guangshan Zhang⁵

Affiliations

¹ College of Resource and Environment, Qingdao Engineering Research Center for Rural Environment, Qingdao Agricultural University, Qingdao 266109, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
² State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
³ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
⁴ College of Resource and Environment, Qingdao Engineering Research Center for Rural Environment, Qingdao Agricultural University, Qingdao 266109, PR China.
⁵ College of Resource and Environment, Qingdao Engineering Research Center for Rural Environment, Qingdao Agricultural University, Qingdao 266109, PR China. Electronic address: gszhanghit@gmail.com.

PMID: 33265040
DOI: 10.1016/j.jhazmat.2020.124011

Abstract

Ag₂O/ZnO/rGO heterojunction photocatalysts were synthesized via a rapid microwave hydrothermal method for photocatalytic degradation of bisphenol A (BPA) under simulated solar light. Ag doping efficiently decreased the bandgap of ZnO, and loading on rGO inhibited the recombination of photoinduced electron-hole pairs. The highest BPA removal rate (80%) was achieved with an Ag doping ratio of 5% and a GO loading ratio of 3 wt%. The enhanced photocatalytic performance was attributed to the narrower bandgap and the improved separation efficiency of electron-hole pairs. Moreover, the recycling experiments proved that Ag₂O/ZnO/rGO possessed excellent photostability. Hole (h⁺) and •OH played crucial roles in the photocatalytic system. The degradation pathway of BPA including hydroxylation and the cleavage of covalent bonds was proposed. The toxicity assessment of intermediates elucidated that most of intermediates were less toxic than BPA. The as-prepared Ag₂O/ZnO/rGO exhibited outstanding photostability and pH adaptability, having great potential to be applied to the degradation of emerging organic pollutants in wastewater.

Keywords: Ag(2)O/ZnO/rGO; Degradation pathway; Simulated solar light; Stability.