Surface engineering of carbon-coated cobalt-doped nickel phosphides bifunctional electrocatalyst for boosting 5-hydroxymethylfurfural oxidation coupled with hydrogen evolution.

Multiple surface/interface engineering is an effective approach to develop efficient electrocatalysts for promoting the practical application of electrocatalysis and achieving carbon neutrality. Herein, a deep eutectic liquid precursor containing phosphorus was designed. The self-supported three-dimensional (3D) cobalt-doped NiP/NiP nanowire networks coated with a thin layer of carbon (Co-NiP@C) were prepared by using an in-situ one-step pyrolysis method. The as-obtained Co-NiP@C hybrid possesses a superaerophobic/superhydrophilic surface, which could promote electrolyte diffusion and enhance bubble release. Density functional theory (DFT) calculations reveal that Co-doping in NiP@C can promote the adsorption and activation of 5-hydroxymethylfurfural (HMF) molecules, and optimize the energy barrier of H* absorption. The self-supported Co-NiP@C was used as an efficient bifunctional electrocatalyst for HMF oxidation coupled with hydrogen evolution reaction (HER) in a 1.0 M KOH solution. A nearly 100 % yield of 2,5-furandicarboxylic acid (FDCA) was achieved. The self-supported Co-NiP@C displayed high activity and stability for both HER and HMF conversion. The HMF oxidation coupled with HER can be efficiently driven by a 1.5 V commercial photovoltaic panel under sunlight. This study lays the foundation for large-scale industrialization in sustainable fine-chemical and energy engineering.