Ru(III)-Modified Trinuclear Nickel Cluster Metal–Organic Framework as a Bifunctional Electrocatalyst for Selective Benzyl Alcohol Oxidation and Accelerating Hydrogen Evolution

Nickel-based materials, due to their low cost, high activity, and dual-function characteristics, have become the most promising catalyst system in the field of biomass electrocatalytic conversion coupled with hydrogen production. The activity of the catalyst and the selectivity of the reaction still present significant challenges. Herein, utilizing the conjugated aromatic tetracarboxylic acids (H₄TCPB = 1,2,4,5-tetrakis(4-carboxyphenyl) benzene), one new trinuclear Ni(II)-based anionic metal-organic framework Li[Ni₃(μ₃-OH)(TCPB)_1.5(H₂O)₃]·6DMA (denoted as Ni-MOF) was first obtained, and its application in electrocatalysis was improved by introducing ruthenium species. And the parent Ni-MOF and Ni-MOF@Ru³⁺-<i>x</i> (<i>x</i> = 1, 2, and 3) exhibit significant electrocatalytic performance for the benzyl alcohol oxidation reaction (BOR). Specially, the Ni-MOF@Ru³⁺-2 achieves a BOR current density of 10 mA cm^-2 under only a low potential of 1.38 V. At 1.46 V (vs RHE), the Ni-MOF@Ru³⁺-2 exhibits a benzyl alcohol conversion of 98.45%, a benzoic acid (Ph-COOH) selectivity of over 97.66%, and a high faraday efficiency of 97.47%. Noteworthy is that a two-electrode Pt/C||Ni-MOF@Ru³⁺-2 electrolyzer could simultaneously promote the effective conversion of benzyl alcohol to benzoic acid and the production of hydrogen at a cell voltage of only 1.48 V. These findings provide a new perspective for the development of bifunctional MOF electrocatalysts for simultaneous production of H₂ and high-value-added chemicals.