An exclusive CO2-to-CO converting single-stack electrolyzer driven by a biomass-derived N-doped carbon-based bimetallic electrocatalyst

Effective carbon capture and its facile conversion into high-value chemicals is reckoned as a practical solution to mitigating the impending climate change effects. Electrochemical conversion of CO2 to other compounds has emerged as one of the leading processes; however, it mostly lingers in the early stage of technology development with poor selectivity and high operational costs. Herein, we present a one-pot synthesis of a carbon-based bimetallic catalyst embedded in a carbon matrix derived from naturally abundant coconut fibers for the selective electrocatalytic reduction of CO2. Incorporating bismuth and nickel as active metals within an N-doped carbon matrix, the catalyst demonstrates an impressive faradaic efficiency of approximately 95% to produce CO while operating at -0.9 V vs. RHE. Further testing of the N-doped carbon supported Bi18Ni8O36 (Bi,Ni/N-C) composite catalyst in an electrolyzer revealed its capability to achieve a current density of 110 mA cm-2 required for industrial-level applications and can produce similar to 1.5 L (60.5 mmol) of CO in 6 hours. Density functional theory (DFT) calculations were conducted to gain deeper insights into the catalytic process, revealing that the nickel metal site exhibits greater activity in facilitating the CO2 reduction reaction (CO2RR). This approach not only enhances the selectivity and efficiency of CO2 conversion processes but also underscores the potential of utilizing cost-effective and biodegradable materials for catalyst design, offering a sustainable pathway to mitigate rising CO2 emissions and produce valuable industrial products.