Selective electroreduction of CO2 into CO over Ag and Cu decorated carbon nanoflakes†

Abstract

The electrocatalytic CO₂ reduction reaction (eCO₂RR) has the potential to effectively cut carbon emission. However, the activity and selectivity of eCO₂RR catalysts are topical due to the intricacy of the reaction components and mechanism. Herein, we have decorated silver and copper nanoparticles over carbon nanoflakes to achieve an Ag–Cu NPs/C system that enables selective reduction of CO₂ into CO. The catalyst is prepared by incorporating Ag nanoparticles into a Cu-BTC MOF (HKUST-1) and subsequent carbonization that alters the surface composition, with improved activity and faradaic efficiency (FE) towards selective CO₂ reduction. The evaluation of electrocatalytic performance reveals that the synthesized catalyst exhibits enhanced electrocatalytic activity and selectivity with a FE_CO of ∼ 90% at −0.79 V_RHE and a current density (j) of 44.15 mA cm⁻² compared to Ag-NPs and Cu/C. The durability test over 40 h confirms the outstanding stability of Ag–Cu NPs/C. The lower Tafel slope value of only 75 mV dec⁻¹ corresponds to the fast reaction kinetics on the surface of Ag–Cu NPs/C. The synthetic protocol in this work offers an easy approach to the betterment of a cost-effective electrocatalyst with improved FE.