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 CO2 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 CO2 reduction. In this work, we report a strategy that enables a CsPbBr3 perovskite for photocatalytic CO2 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 CsPbBr3/ZnPc heterojunction provides the catalytically active sites in ZnPc with sufficient energetic electrons for CO2 methanation. As a result, CsPbBr3/ZnPc achieves selectivity up to 89% and activity of 168 μmol g–1 h–1 for CH4 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.