Carbon dots/Bi2WO6 composite with compensatory photo-electronic effect for overall water photo-splitting at normal pressure

Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H-2 energy by semiconductors. However, the band structure of many semiconductors cannot satisfy the requirement of H-2 and O-2 production at the same time. Herein, we illustrate that carbon dots (CDs)/Bi2WO6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent. In this complex photocatalytic system, the photo-potential provided by CDs makes the CDs/Bi2WO6 (C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting. The C-BWO composite (3 wt% CDs content) exhibits optimized hydrogen evolution (oxygen evolution) of 0.28 mu mol/h (0.12 mu mol/h) with an approximate 2:1 (H-2:O-2) stoichiometry at normal pressure. We further employed the in-situ transient photovoltage (TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

The study demonstrates enhanced activity of carbon dots/Bi2WO6 photocatalyst for overall water photo-splitting without sacrificial agent. Through compensatory photo-electronic effect, the composite can satisfy band structure conditions for water photo-splitting and exhibits optimized hydrogen evolution rate.