DataSheet1_Boosting Electrochemical Carbon Dioxide Reduction on Atomically Dispersed Nickel Catalyst.docx

Single-atom catalysts (SACs) with metal–nitrogen (M–N) sites are one of the most promising electrocatalysts for electrochemical carbon dioxide reduction (ECO2R). However, challenges in simultaneously enhancing the activity and selectivity greatly limit the efficiency of ECO2R due to the improper interaction of reactants/intermediates on these catalytic sites. Herein, we report a carbon-based nickel (Ni) cluster catalyst containing both single-atom and cluster sites (NiNx-T, T = 500–800) through a ligand-mediated method and realize a highly active and selective electrocatalytic CO2R process. The catalytic performance can be regulated by the dispersion of Ni–N species via controlling the pyrolysis condition. Benefitting from the synergistic effect of pyrrolic-nitrogen coordinated Ni single-atom and cluster sites, NiNx-600 exhibits a satisfying catalytic performance, including a high partial current density of 61.85 mA cm−2 and a high turnover frequency (TOF) of 7,291 h−1 at −1.2 V vs. RHE, and almost 100% selectivity toward carbon monoxide (CO) production, as well as good stability under 10 h of continuous electrolysis. This work discloses the significant role of regulating the coordination environment of the transition metal sites and the synergistic effect between the isolated single-site and cluster site in enhancing the ECO2R performance.具有金属-氮（M–N）位点的单原子催化剂（SACs）是用于电化学二氧化碳还原（ECO₂R）的最具应用前景的电催化剂之一。然而，由于反应物/中间体在这些催化位点上的相互作用不当，同时提升活性与选择性的挑战极大限制了ECO₂R的反应效率。于此，我们通过配体介导法制备了一种同时包含单原子与团簇位点的碳基镍（Ni）团簇催化剂（NiNₓ-T，T=500–800），并实现了高活性、高选择性的电催化CO₂R过程。催化性能可通过调控热解条件来改变Ni–N物种的分散度进行调节。得益于吡咯氮配位的镍单原子与团簇位点的协同效应，NiNₓ-600展现出优异的催化性能：在相对于可逆氢电极（RHE）的-1.2 V电位下，其分电流密度高达61.85 mA cm⁻²，周转频率（TOF）达到7291 h⁻¹，对一氧化碳（CO）生成的选择性接近100%，且在10小时连续电解过程中表现出良好的稳定性。本研究揭示了调控过渡金属位点配位环境，以及孤立单一位点与团簇位点间的协同效应，在提升ECO₂R性能中的关键作用。