Cu-BTC-confined synthesis of Cu-Cu2O-CuS nanojunctions embedded in a porous carbon matrix for remarkable photothermal CO2 conversion

Abstract

Photothermal catalytic CO₂ reduction into fuels using solar energy is an ideal strategy to reduce CO₂ emission while producing value-added carbon compounds. However, developing low-cost and high-efficiency photothermal catalysts remains a significant challenge. Herein, photothermal hybrid catalysts (Cu-Cu₂O-CuS@C), highly dispersed Cu-Cu₂O-CuS nanojunctions (sub-10 nm) confined within a porous nitrogen-doped carbon octahedron matrix, are designed and fabricated through a simple pyrolysis-oxidation-sulfidation route using the prepared copper benzene-1,3,5-tricarboxylate (Cu-BTC) octahedra as the precursor. The prepared Cu-Cu₂O-CuS@C sample exhibits a significant photothermal conversion effect, and more photons can be converted into thermal energy for promoting photoredox catalysis. Meanwhile, the formed Cu₂O-CuS p–n nanojunction and Cu-Cu₂O-CuS Schottky junction greatly accelerate charge transport, fundamentally expose more catalytic active sites and improve reactant adsorption. Thus more electrons could be excited and relaxed to participate in CO₂ reduction reactions. These positive factors make the optimized Cu-Cu₂O-CuS@C catalyst demonstrate remarkable photothermal catalytic activity toward CO₂ conversion into CO (22.6 μmol h⁻¹ g⁻¹) and CH₄ (3.06 μmol h⁻¹ g⁻¹). This work provides a rational strategy to fabricate efficient photothermal catalysts for solar energy utilization and conversion.