Single nickel atoms confined in N-doped porous carbon for CO2 electroreduction coupled with pollutants degradation

Single-atom catalysts (SACs) have exhibited great potential for CO 2 electroreduction (CO 2 RR), but designing highly active and cost-effective SACs remains a challenge. In this study, a pyrolysis strategy with space-limiting materials as the precursors is developed to synthesize a highly active Ni-SAs/NC catalyst, and an atomic Ni loading of 2.16 wt% is achieved. The coordination style of Ni atoms is determined to be Ni-N 3 by XAS. During the CO 2 RR test, a CO Faradaic efficiency of 98.21 % at -0.8 V vs. RHE can be achieved with a turnover frequency of 2378 h -1 . A long-term stability can also be obtained with negligible deactivation in 24 h, surpassing most of previously reported non-noble metal catalysts. In addition, a novel dual-function reaction system was fabricated to integrate CO 2 RR with electrochemical oxidation processes (EAOPs) for pollutants degradation. With δ-MnO 2 /NF as the anode, 100 % of 40 ppm RhB can be degraded within 30 min in the range of -0.6 V ∼ -1.0 V. This system can thus enable the reduction of CO 2 to CO and degradation of pollutants in the anodic cell simultaneously. The introduction of EAOPs as the anodic reaction provides a more cost-effective method for electrochemical CO 2 reduction.