Ultrathin graphene encapsulated Cu nanoparticles: A highly stable and efficient catalyst for photocatalytic H2 evolution and degradation of isopropanol

Cu is a promising candidate for developing efficient and cost-effective catalysts for metal-induced photocatalysis. A highly desirable yet great challenge is the preparation of stable Cu-based photocatalysts, and its application in photocatalytic H2 evolution and photodegradation are desirable to explore. In this study, ultrathin graphene-coated metal Cu nanoparticles (NPs) are fabricated through a two-step pyrolysis process using MOFs as precursors and show remarkable stability even in an oxidative atmosphere. Benefiting from the nanostructure, the optimized [email protected]/SrTiO3 shows a photocatalytic H2 evolution rate of 255.3 µmol·g−1·h−1, and the apparent quantum efficiency (AQE) reaches 3.8% at 420 nm. The acetone evolution rate of [email protected]/SrTiO3 is approximately 21-fold higher than that of Cu/STO in photocatalytic isopropyl alcohol (IPA) degradation under visible light. Moreover, the graphene layer demonstrated a quasi-cocatalyst effect. Time-resolved photoluminescence and theoretical calculations reveal that the ultrathin graphene layer promotes charge separation and induces electron density redistribution over [email protected], which distinctly boosts H2 evolution. This work provides an effective method to protect Cu NPs and a broader prospect for exploring non-precious Cu-based nanocomposites in photocatalytic conversion.