A Lead-Free 0D/2D Cs 3 Bi 2 Br 9 /Bi 2 WO 6 S-Scheme Heterojunction for Efficient Photoreduction of CO 2 .

Photocatalytic reduction of CO into valuable hydrocarbon fuels is one of the green ways to solve the energy problem and achieve carbon neutrality. Exploring photocatalyst with low toxicity and high-efficiency is the key to realize it. Here we report a lead-free halide perovskite-based 0D/2D CsBiBr/BiWO (CBB/BWO) S-scheme heterojunction for CO photoreduction, prepared by a facile electrostatic self-assembly approach. The CBB/BWO shows superior photoreduction of CO under visible light with CO generation rate of 220.1 μmol·g·h, which is ∼115.8 and ∼18.5 times higher than that of CsBiBr perovskite quantum dots (CBB PQDS) and BiWO nanosheets (BWO NS), respectively. The improved photocatalytic activity can be attributed to the tight 0D/2D structure and S-scheme charge transfer pathway between the CsBiBr PQDS and atomic layers of the BiWO NS, which shortens transmission distance of photogenerated carriers and boosts efficient separation and transfer of the carriers. This work provides insight in manufacturing potential lead-free perovskite-based photocatalysts for achieving carbon neutrality.