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 CO ₂ photoreduction. The product yields slightly decreased in the 7^th 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.