Template-sacrificing synthesis of well-defined asymmetrically coordinated single-atom catalysts for highly efficient CO₂ electrocatalytic reduction

• Main Authors: Huang, Ming, Deng, Bangwei, Zhao, Xiaoli, Zhang, Zheye, Li, Fei, Li, Kanglu, Cui, Zhihao, Kong, Lingxuan, Lu, Jianmei, Dong, Fan, Zhang, Lili, Chen, Peng
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Chemical technology; Ni Single-Atom Catalysts; Coordination Environment
• Online Access: https://hdl.handle.net/10356/161637
• Institution: Nanyang Technological University

Although various single-atom catalysts have been designed, atomically engineering their coordination environment remains a great challenge. Herein, a one-pot template-sacrificing pyrolysis approach is developed to synthesize well-defined Ni-N4-O catalytic sites on highly porous graphitic carbon for electrocatalytic CO2 reduction to CO with high Faradaic efficiency (maximum of 97.2%) in a wide potential window (-0.56 to -1.06 V vs RHE) and with high stability. In-depth experimental and theoretical studies reveal that the axial Ni-O coordination introduces asymmetry to the catalytic center, leading to lower Gibbs free energy for the rate-limiting step, strengthened binding with *COOH, and a weaker association with *CO. The present results demonstrate the successful atomic-level coordination environment engineering of high-surface-area porous graphitic carbon-supported Ni single-atom catalysts (SACs), and the demonstrated method can be applied to synthesize an array of SACs (metal-N4-O) for various catalysis applications.