Abstract
In this study, we propose a practical approach for producing a heterobimetallic Ni(II)-Ce(III) diimine complex from an extended salen-type ligand (H(2)L) to serve as an electrocatalyst for CO(2) reduction and demonstrate an outstanding overall efficiency of 99.6% of the cerium-nickel complex and integrate it into applicable cell assemblies. We optimize not only the catalyst, but the operational conditions enabling successful CO(2) electrolysis over extended periods at different current densities. A comparison of electrochemical behavior in H-cell and zero-gap cell electrolyzers suggests potential applications for industrial scale-up. In the H-cell electrolyzer configuration, the most elevated efficiency in CO production was achieved with a selectivity of 56.96% at -1.01 V vs RHE, while HCOO(-) formation exhibited a selectivity of 32.24% at -1.11 V vs RHE. The highest TON was determined to be 14657.0 for CO formation, followed by HCOO(-) with a TON of 927.8 at -1.11 V vs RHE. In the zero-gap electrolyzer configuration, the most efficient setup toward CO production was identified at a current density (CD) of 75 mA cm(-2), a flow rate of 10 mL min(-1), operating at 60 °C and utilizing a low KOH concentration of 0.1 M to yield a maximum faradaic efficiency (FE(CO)) of 82.1% during 24 h of stable electrocatalysis.