Metastable Phase Noble-Metal-Free Core-Shell Structure for Efficient Electrocatalytic Nitrobenzene Transfer Hydrogenation.

Xiong, Yutian; Chen, Jinxin; Wang, Yue; Wang, Qun; Liu, Da; Shao, Qi; Lu, Jianmei · Nano Lett · 2025

basic_science · Level V

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Abstract

In order to study the catalytic behavior of a metastable-phase catalyst in electrocatalytic hydrogenation, we report a new metastable-phase noble-metal-free core-shell catalyst with a metastable hexagonal closest packed (hcp) phase Ni as the shell and face-centered-cubic (fcc) phase Cu as the core (Cu@hcp Ni NPs) for electrocatalytic hydrogenation of nitrobenzene (Ph-NO<sub>2</sub>) to aniline (Ph-NH<sub>2</sub>). Using H<sub>2</sub>O as the hydrogen source, it achieves up to 99.63% Ph-NO<sub>2</sub> conversion and ∼100% Ph-NH<sub>2</sub> selectivity, with an improved activity turnover frequency (TOF: 6640 h<sup>-1</sup>), much higher than those of hcp Ni NPs (5183.7 h<sup>-1</sup>) and commercial Pt/C (3537.6 h<sup>-1</sup>). It can also deliver a variety of aminoarenes with outstanding selectivity and excellent functional group compatibility with several groups. Mechanistic studies have shown that the introduction of Cu enhances hcp Ni's ability to dissociate water <i>in situ</i> to produce H* and improves the hydrogenation rate, resulting in the rapid conversion of Ph-NO<sub>2</sub> to the final product Ph-NH<sub>2</sub>.