Ni single-atom arrays as self-supported electrocatalysts for CO₂RR

Developing highly active, selective, and stable electrocatalysts for the CO2 reduction reaction (CO2RR) is essential to relieve the greenhouse effect and the energy crisis. Traditional catalytic electrodes require ionomer binders, which inevitably impose undesired high CO2 transport resistance and block the active sites. Herein, Ni single atoms anchored on nitrogen-doped carbon nanoarrays (denoted as Ni-SAC-NA) were developed as the electrode without additional ionomers for efficient CO2RR. The unique nanoarray structure provided a higher specific surface area, more exposed active sites, and enhanced electron/mass transport due to its short diffusion pathway and ionomer-free nature. As a result, the Ni-SAC-NA electrode exhibited enhanced activity of CO2RR and selectivity towards CO with Faradaic efficiency of 96.7%, turnover frequency of 27,504 h(-1), and cathodic energy efficiencies of 54.9% at -0.88 V (vs. RHE). Our findings provide a rational design strategy for CO2RR electrocatalysts by constructing ionomer-free electrodes.