Engineering active Ni-doped Co₂P catalyst for efficient electrooxidation coupled with hydrogen evolution

The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction (HER) is considered as a sustainable and promising technique. Nonetheless, it remains a great challenge due to the lack of simple, cheap, and high-efficient electrocatalysts. Here, we successfully develop a simple and scalable electro-deposition and subsequent phosphorization route to fabricate Ni-doped Co₂P (Ni-Co₂P) nanosheets catalyst using the in-situ released Ni species from defective Ni foam as metal source. Impressively, the as-synthesized Ni-Co₂P catalyst exhibits excellent electrochemical 5-hydroxymethylfurfural oxidation reaction (HOR) performance with > 99% 2,5-furandicarboxylic acid yield and > 97% Faradaic efficiency at an ultralow potential of 1.29 V vs. reversible hydrogen electrode (RHE). Experimental characterization and theoretical calculation reveal that the atomically doped Ni species can enhance the adsorption of reactant and thus lower the reaction energy barriers. By coupling the electrocatalytic HOR with HER, the employed two-electrode system using Ni-Co₂P and commercial Ni foam as anode and cathode, respectively, exhibits a low cell voltage of 1.53 V to drive a current density of 10 mA·cm⁻², which is 90 mV lower than that of pure water splitting. This work provides a facile and efficient approach for the preparation of high-performance earth-abundant electrocatalysts toward the concurrent production of H₂ and value-added chemicals.