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 2 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 Cs 3 Bi 2 Br 9 /Bi 2 WO 6 (CBB/BWO) S-scheme heterojunction for CO 2 photoreduction, prepared by a facile electrostatic self-assembly approach. The CBB/BWO shows superior photoreduction of CO 2 under visible light with CO generation rate of 220.1 μmol·g -1 ·h -1 , which is ∼115.8 and ∼18.5 times higher than that of Cs 3 Bi 2 Br 9 perovskite quantum dots (CBB PQDS) and Bi 2 WO 6 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 Cs 3 Bi 2 Br 9 PQDS and atomic layers of the Bi 2 WO 6 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.