N, S-coordinated Ni single-atom catalysts for efficient CO2 reduction in a zero-gap membrane electrode assembly electrolyzer

Nickel single-atom catalysts (Ni SACs) hold great promise for the electrochemical CO2 reduction reaction (CO2RR) to CO. However, there remains a lack of synthetic strategies for achieving high CO2RR performance in a zero-gap electrolyzer. Herein, we demonstrate asymmetrically coordinated Ni SACs and membrane electrode assembly (MEA) structures to achieve outstanding CO2RR performance in a zero-gap electrolyzer. N, S-coordinated Ni SAC with the Ni-N3S1 structure (Ni-NSC-1) showed a higher Faradaic efficiency (FECO) and partial current density (jCO) of CO than N-coordinated Ni SACs (Ni-NCs). This was due to the coordination environment of Ni and increased N and S content in the carbon support. The FECO, jCO, and stability of the Ni-NSC-1 were further improved by modulating the MEA structure and operating temperature. As a result, a maximum FECO of 92.85% (at 2.1 V) and jCO of 286.54 mA/cm2 (at 2.3 V) were achieved using a Sustainion X37-50 GT membrane at 343 K. Moreover, the Ni-NSC-1 with Sustainion X3750 GT exhibited long-term stability for over 60 h, maintaining a high FECO of 95% at 100 mA/cm2. (c) 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.