Tailoring of Graphene-Modified Cu-MOFs for Improved Controllable CO2 Electroreduction Toward CH4 Production

A series of graphene-modified copper–metal–organic framework composites (G-Cu-MOF-0.3, G-Cu-MOF-0.5, G-Cu-MOF-1) were fabricated via a solvothermal method. Structural characterizations verified that graphene was successfully composited without damaging the Cu-MOF crystalline framework, among the four materials, G-Cu-MOF-0.5 exhibits the largest specific surface area and pore size. Electrochemical results showed that G-Cu-MOF-0.5 displayed the best CO₂ electroreduction performance, with a current density of − 11 mA cm⁻², a double-layer capacitance (Cdl) of 4.97 mF cm⁻² and a Tafel slope value of 36.5 mV dec⁻¹. At − 1.5 V vs. RHE, the total Faradaic efficiency for CH₄ and CO reached 24% with stable operation over 12 h. Graphene modification significantly improves the conductivity, active site density, and structural stability of Cu-MOF, realizing efficient and controllable CO 2 conversion to C1 products. The hydrogen evolution reaction (HER) remains the dominant side reaction, and the Faradaic efficiency toward CH 4 is still moderate, leaving room for further selectivity optimization.This work provides a feasible strategy for designing MOF–carbon composites for electrocatalytic CO₂ reduction to methane.