Enabling CsPbBr₃ Perovskites for Photocatalytic CO₂ Methanation by Rationalizing a Z-Scheme Heterojunction with Zinc Phthalocyanine

Perovskite materials are regarded as promising photocatalysts for light harvesting, yet they exhibit low photocatalytic activity due to serious charge recombination and lack of efficient catalytic sites toward CO 2 reduction. Previous studies have employed perovskites as reductive sides in a Z-scheme heterojunction to suppress charge recombination, which however still encounter low activity and selectivity because of the absence of specific catalytic sites for CO 2 reduction. In this work, we report a strategy that enables a CsPbBr 3 perovskite for photocatalytic CO 2 methanation. The central concept is the construction of a Z-scheme heterojunction using zinc phthalocyanine (ZnPc) as the reductive side. The enhanced charge separation in the CsPbBr 3 /ZnPc heterojunction provides the catalytically active sites in ZnPc with sufficient energetic electrons for CO 2 methanation. As a result, CsPbBr 3 /ZnPc achieves selectivity up to 89% and activity of 168 μmol g –1 h –1 for CH 4 production, well exceeding all of the reported perovskite-based photocatalysts. This work provides insights into the rational design of perovskite-based heterojunctions for artificial photosynthesis.