Copper modification of pyrite for CO₂ electrochemical reduction

CO₂ electrocatalytic reduction to synthesize highly value-added fuels provides a sustainable path for CO₂ conversion and utilization. Nevertheless, the development of electrocatalysts with high catalytic activity and product selectivity remains a major challenge. In this work, copper-doped FeS₂ catalysts (Cu_xFe_1−xS₂) were prepared for CO₂ electrochemical reduction. The physicochemical properties of the catalysts were studied by XRD, XPS, SEM and other characterization analysis methods. Experimental results show that Cu doping can control the size of the catalyst nanosheets and inhibit the oxidation of FeS₂ in the air. Cu_0.33Fe_0.67S₂ shows better catalytic activity for CO₂ electrocatalytic reduction than FeS₂. In the potential range of (−1.5) − (−1.6) V vs. RHE, the total efficiency of carbon-containing products of CO₂ electrocatalytic reduction is 50.8% and its current density is 23.8 mA/cm², which increases by 71.2% compared with FeS₂ catalyst. The Faradaic efficiency of Cu_0.09Fe_0.91S₂ to produce C₃H₆ at −1.3 V vs. RHE is 21.8%, which is significantly higher than the value reported in the current literature. Thus, Cu_xFe_1−xS₂ is regarded as an excellent electrocatalyst for CO₂ reduction.