The electrocatalytic reduction of carbon dioxide (CO2) is considered an effective strategy for mitigating the energy crisis and the greenhouse effect. Nickel is widely used in single-atom catalysts (SACs) owing to its special electronic structure. In this minireview, the basic principles of Ni SACs in the electrocatalytic reduction of CO2 to CO are first described. Subsequently, Ni SACs are divided into three categories depending on different strategies used to improve properties. The synthesis, morphology, performance and theoretical calculations of the catalysts are also described. Finally, an overview of the existing challenges and perspectives of Ni SACs for CO2 reduction is presented.
The electrocatalytic conversion of carbon dioxide (CO2) into useful fuels and chemical feedstocks is an emerging route to alleviate global warming and reduce reliance on fossil fuels. Methanol (CH3OH), as one of the most significant and widely used liquid fuels that can be generated by CO2 reduction, is essential in the chemical industry. In this minireview, we unravel the origins of the selective formation of CH3OH via CO2 reduction, including catalyst composition designs, local structure modulations, and electrolyte/catalyst interface regulations. Finally, the remaining challenges and perspectives for the CO2-to-CH3OH reduction are proposed.
Electrochemical reduction of CO2 to valuable formate as liquid fuel is a promising way to alleviate the greenhouse effect. The edge active sites in bismuth (Bi) nanosheets play a critical role in the electrochemical reduction of CO2 into formate, which enable the operation of CO2 reduction with high cathodic energy efficiency, especially under large current densities of ≥ 200 mA/cm2. However, the undesirable reconstruction of small Bi nanosheets into large nanosheets leads to the decreasing of edge active sites during electrocatalysis. Here we report stable isolated ultrasmall bismuth nanosheets-synthesized by in-situ electrochemical transformation of ligands covered bismuth vanadate-on silver nanowires as an efficient electrocatalyst for CO2-to-formate reduction. The cooperative electrocatalyst achieves a formate current density of 186 mA/cm2 and a cathodic energy efficiency of 75% for formate, which is the only best compared to the literature results. Operando Raman and morphologic measurements demonstrate that the excellent energy utilization of the electrocatalyst is originated from the rich edge active sites with Bi-O species of the ultrasmall Bi nanosheets.