Superior CO₂ Electroreduction Performance on Co-Ni-Nitrogen Bimetallic Sites

The electrochemical reduction of carbon dioxide (CO₂ ECR) plays a crucial role in transitioning towards a sustainable energy and chemical industry. This process has the potential to not only address the rising CO₂ levels but also utilize it as a resource to produce valuable fuels and chemicals. Electrocatalysts are essential in CO₂ ECR, as their ability to selectively and efficiently convert CO₂ offers significant environmental and economic benefits. Our research, focusing on nanostructured electrocatalysts for energy applications, introduces an innovative nanostructured catalyst that represents a significant advancement in CO₂ ECR technology for energy generation and conversion.<br/>Regarding CO₂ ECR, a wide range of catalysts including metals, alloys, metal oxides, functionalized carbons, and metal complexes have been studied for their effectiveness. Despite their remarkable CO₂ conversion capacity, challenges such as sub-optimal energy efficiency, varying activity levels, and undesired hydrogen evolution reactions (HER) present significant obstacles. Addressing these challenges, our study introduces a novel electrocatalyst featuring diatomic metal-nitrogen sites (Co-Ni-N-C). This catalyst is synthesized through a unique process involving ion exchange using a zeolitic imidazolate framework (ZIF) as a precursor, followed by pyrolysis. This method results in nitrogen-doped graphitic carbon, effectively anchoring the Co-Ni bimetallic active sites.<br/>This work highlights the potential of nanostructured single-atom catalysts (SACs) and dual-active site catalysts (DASCs) in CO₂ ECR. Transition metal SACs, such as Ni-SAC on nitrogen-doped graphene, have previously shown promising results in CO₂ conversion efficiency. However, our Co-Ni-N-C catalyst takes a step forward by demonstrating a CO yield rate of 53.36 mA mg cat.⁻¹ and a CO Faradaic efficiency of 94.1% at an overpotential of -0.27 V. This performance showcases that Co-Ni-N₆ moiety plays a crucial synergistic role in promoting and sustaining these exceptional ECR activities<br/>Spectroscopic, microscopic, and density functional theory analyses collectively reveal the synergistic role played by the Co-Ni-N6 moiety in enhancing catalytic activity. This synergy is crucial in promoting and sustaining exceptional ECR activities. The findings not only emphasize the effectiveness of nanostructuring in electrocatalyst design but also shed light on the pathways for developing various advanced catalysts for sustainable energy conversion. Therefore, our study offers a novel perspective in the field of CO₂ ECR, opening new avenues for the development of efficient, nanostructured catalysts for energy applications.