Coordination environment tuning of nickel sites by oxyanions to optimize methanol electro-oxidation activity.

Li, Shanlin; Ma, Ruguang; Hu, Jingcong; Li, Zichuang; Liu, Lijia; Wang, Xunlu; Lu, Yue; Sterbinsky, George E et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

To achieve zero-carbon economy, advanced anode catalysts are desirable for hydrogen production and biomass upgrading powered by renewable energy. Ni-based non-precious electrocatalysts are considered as potential candidates because of intrinsic redox attributes, but in-depth understanding and rational design of Ni site coordination still remain challenging. Here, we perform anodic electrochemical oxidation of Ni-metalloids (NiP<sub>x</sub>, NiS<sub>x</sub>, and NiSe<sub>x</sub>) to in-situ construct different oxyanion-coordinated amorphous nickel oxyhydroxides (NiOOH-TO<sub>x</sub>), among which NiOOH-PO<sub>x</sub> shows optimal local coordination environment and boosts electrocatalytic activity of Ni sites towards selective oxidation of methanol to formate. Experiments and theoretical results demonstrate that NiOOH-PO<sub>x</sub> possesses improved adsorption of OH* and methanol, and favors the formation of CH<sub>3</sub>O* intermediates. The coordinated phosphate oxyanions effectively tailor the d band center of Ni sites and increases Ni-O covalency, promoting the catalytic activity. This study provides additional insights into modulation of active-center coordination environment via oxyanions for organic molecules transformation.