Ni single atoms supported on hierarchically porous carbonized wood with highly active Ni-N sites as a self-supported electrode for superior CO electroreduction.

Powdery N-doped carbon-supported single-atom catalysts (SACs) can be prepared on a large scale and are highly selective in converting CO to CO, but their practical application is restricted by their powdery texture. Herein, we report Ni single atoms supported on hierarchically porous N-doped carbonized wood (Ni SAs-NCW) as a self-supported electrode for efficient and durable CO electroreduction. The porous NCW matrix possesses an abundance of open aligned microchannels that allow unimpeded CO diffusion and electrolyte transportation while the uniformly dispersed Ni SAs in the NCW matrix in the Ni-N configuration afford ample highly active sites for CO electroreduction. This Ni SAs-NCW electrode exhibits a high CO-to-CO faradaic efficiency (FE) of 92.1% and a CO partial current density () of 11.4 mA cm at -0.46 V the reversible hydrogen electrode (RHE) and maintains a stable FE and over a period of 9 h of electrolysis. This work provides an effective strategy to develop efficient SACs with potential to be integrated into flow cell systems for large-scale CO reduction.