Direct Z-scheme heterojunction of PCN-222/CsPbBr3 for boosting photocatalytic CO2 reduction to HCOOH

•PCN-222/CsPbBr3 was fabricated by an electrostatic self-assembly method.•PCN-222/CsPbBr3 exhibits enhanced visible-light photocatalytic activity in CO2-to-HCOOH conversion.•The Z-Scheme heterojunction is responsible for the photocatalytic improvement.•The mechanism of the photocatalytic CO2RR over PCN-222/CsPbBr3 is proposed. Exploring photocatalysts with efficient charge separation to boost CO2 reduction to valuable chemicals is of great significance. Herein, we develop a PCN-222/CsPbBr3 hybrid with direct Z-scheme heterojunction for high-efficiency photoreduction of CO2 to HCOOH. By delicately controlling the interface of the PCN-222/CsPbBr3 hybrid, effective electron transfer from CsPbBr3 to PCN-222 is achieved, leading to the construction of an internal electric field (IEF). The photo-induced electrons transfer from PCN-222 to CsPbBr3 under visible light irradiation derived from IEF is confirmed by in-situ X-ray photoelectron spectroscopy (XPS), transient absorption (TA), and Kelvin probe force microscopy (KPFM), resulting in the impactful spatial separation of electron-hole pairs. The optimized PCN-222/CsPbBr3 catalyst with direct Z-scheme heterojunction finally offers a 7.0- and 2.1-times enhancement in CO2 photoreduction to HCOOH compared to pristine PCN-222 and CsPbBr3, respectively. This work provides a facile strategy for developing superior perovskite-based CO2RR photocatalysts with both high catalytic activity and selectivity of value-added products.