Ultralow-coordinated Ni species boosting paired electrosynthesis of formate from waste plastic and carbon dioxide
Tao Chen, Qizhi Hu, Chao Wu, Mingdong Sun, Ping Fu, Xiaoling Liu, Yulong Li, Yu Zhou, Shibo Xi, Jun Wang
Abstract
Paired electrolysis of waste feedstocks holds an energy-efficient alternative for chemical production; however, the sluggish anodic oxidation limited the total efficiency under larger current density. Herein, we constructed ultralow-coordinated Ni species with Ni–O coordination number of ∼3 via a hydrothermal synthesis-sulfidation-annealing process and electrochemical activation and demonstrated the vital role in accelerating the proton deintercalation and reactive oxygen intermediate ·OH formation during electro-reforming polyethylene terephthalate hydrolysate (POR). The target catalyst NiCoSx/NF afforded a high formate productivity of 7.4 mmol cm −2 h −1 at ∼600 mA cm −2 with a formate Faradic efficiency (FE formate ) of 92.4% in POR and maintained a FE formate of ∼90% for 100 h at 2 A in a membrane electrode assembly electrolyzer. Coupling POR on NiCoSx/NF with carbon dioxide reduction reaction on oxygen vacancies enriched Vo-BiSnO reached effective concurrent formate production with 172.7% of FE formate at 500 mA cm −2 and long-term stability. Such excellent performance shows the great prospect of electrocatalyst design by regulating the local metal environment.