Nitrogen Vacancy Induced Coordinative Reconstruction of Single‐Atom Ni Catalyst for Efficient Electrochemical CO2 Reduction

• Published in: Advanced functional materials 2021-12, Vol.31 (51), p.n/a
• Main Authors: Jia, Chen, Li, Shunning, Zhao, Yong, Hocking, Rosalie K., Ren, Wenhao, Chen, Xianjue, Su, Zhen, Yang, Wanfeng, Wang, Yuan, Zheng, Shisheng, Pan, Feng, Zhao, Chuan
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon dioxide; Carbon monoxide; CO 2 reduction; Coordination; Density functional theory; Materials science; microwave‐induced plasma; Nitrogen; nitrogen vacancy; Reconstruction; Reduction (metal working); Selectivity; Single atom catalysts; single‐atom catalyst; Transition metals; unsaturated coordination; Vacancies
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202107072

Transition metal nitrogen carbon based single‐atom catalysts (SACs) have exhibited superior activity and selectivity for CO2 electroreduction to CO. A favorable local nitrogen coordination environment is key to construct efficient metal‐N moieties. Here, a facile plasma‐assisted and nitrogen vacancy (NV) induced coordinative reconstruction strategy is reported for this purpose. Under continuous plasma striking, the preformed pentagon pyrrolic N‐defects around Ni sites can be transformed to a stable pyridinic N dominant Ni‐N2 coordination structure with promoted kinetics toward the CO2‐to‐CO conversion. Both the CO selectivity and productivity increase markedly after the reconstruction, reaching a high CO Faradaic efficiency of 96% at mild overpotential of 590 mV and a large CO current density of 33 mA cm‐2 at 890 mV. X‐ray adsorption spectroscopy and density functional theory (DFT) calculations reveal this defective local N environment decreases the restraint on central Ni atoms and provides enough space to facilitate the adsorption and activation of CO2 molecule, leading to a reduced energy barrier for CO2 reduction. A nitrogen vacancy (NV) induced coordinative reconstruction is realized, by increasing plasma treating time, to construct a defective and unsaturated Ni‐pyridinic N2 coordination structure with superior CO2 reduction activity. This local N environment decreases the restraint on central Ni atoms and provides enough space which favors the adsorption and activation of CO2 molecule, leading to a reduced energy barrier for CO2 reduction.