PtCu thickness-modulated interfacial charge transfer and surface reactivity in stacked graphene/Pd@PtCu heterostructures for highly efficient visible-light reduction of CO2 to CH4

Photocatalytic conversion of CO2 to chemical feedstocks represents an intriguing approach to address the energy and environmental crisis, but faces low conversion efficiencies resulted from unsatisfied light absorption, charge recombination and surface reactivity of traditional semiconductor photocatalysts. Herein, we report stacked graphene/[email protected] nanostructures with atomically thin PtCu shell to overcome above challenges and realize high-efficient CO2-to-CH4 photoreduction. The smart design begins with the excitation of Ru complex with broad visible absorption, which is followed by the smooth movement of photoelectrons via the graphene→Pd→PtCu pathway, and then the highly selective CO2 reduction on the PtCu surface. As the PtCu thickness decreases, the strengthened Pd–PtCu interfacial charge polarization contributes to improved charge separation/migration. Meanwhile, CO2 adsorption on the PtCu surface is ameliorated owing to increased electron accumulation and compressive strain. This work provides a new design for boosting the photocatalytic performance by cooperative surface and interfacial modulations.