Controllable synthesized step-scheme heterojunction of CuBi2O4 decorated WO3 plates for visible-light-driven CO2 reduction

Rational design and construction of step-scheme (S-scheme) photocatalyst has received much attention in the field of CO2 reduction because of its great potential to solve the current energy and environmental crises. In this study, a series of plate-like WO3/CuBi2O4 (WO/CBO) photocatalysts were synthesized. The CO and CH4 yields over optimal composite reached 1, 115.8 and 67.2 µmol/m2 after 9 h visible light illumination (λ > 400 nm), which was higher than those of two pure catalysts in CO2 photoreduction. The product yields slightly decreased in the 7th cycling. Besides, the staggered band structure of heterojunction was characterized by diffuse reflectance spectroscopy (DRS) and valence band-X-ray photoelectron spectroscopy (VB-XPS), and a S-scheme charge transfer mechanism was verified by detecting electron spin resonance (ESR) and XPS result about surface composition of WO/CBO catalyst in dark or light. This work may be useful for rational designing of S-scheme photocatalyst and provides some illuminating insights into the S-scheme transfer mechanism.