Replacing oxygen evolution reaction (OER) by electrooxidations of organic compounds has been considered as a promising approach to enhance the energy conversion efficiency of the electrolytic water splitting proces. Developing efficient electrocatalysts with low potentials and high current densities is crucial for the large‐scale productions of H2 and other value‐added chemicals. Herein, non‐noble metal electrocatalysts Co‐doped Ni3S2 self‐supported on a Ni foam (NF) substrate are prepared and used as catalysts for 5‐hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) under alkaline aqueous conditions. For HMFOR, the Co0.4NiS@NF electode achieves an extremely low onset potential of 0.9 V versus reversible hydrogen electrode (RHE) and records a large current density of 497 mA cm–2 at 1.45 V versus RHE for HMFOR. During the HMFOR‐assisted H2 production, the yield rates of 2,5‐furandicarboxylic acid (FDCA) and H2 in a 10 mL electrolyte containing 10 × 10−3 M HMF are 330.4 µmol cm–2 h–1 and 1000 µmol cm–2 h–1, respectively. The Co0.4NiS@NF electrocatalyst displays a good cycling durability toward HMFOR and can be used for the electrooxidation of other biomass‐derived chemicals. The findings present a facile route based on heteroatom doping to fabricate high‐performance catalyses that can facilitate the industrial‐level H2 production by coupling the conventional HER cathodic processes with HMFOR.

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A Co-doped FeNi carbonate hydroxide nanosheet array supported on nickel foam served as an efficient oxygen evolution electrocatalyst with a high activity and excellent stability.

The utilization of biomass resources is essential for constructing a carbon neutral society. Electrochemical conversion of biomass-derived platform molecule 5-hydroxymethylfurfural (HMF) to 5-furandicarboxylic acid (FDCA) is a highly promising alternative pathway for the production of valuable biobased oxygenated chemicals, which primarily takes advantage of the ongoing development of efficient, robust, and inexpensive catalysts. In the present work, a carbon paper-supported nickel-iron layered double hydroxide (LDH) nanosheet array implanted with abundant cationic vacancies (d-NiFe LDH/CP) is employed as a self-standing electrode for oxidation of HMF to FDCA. A 97.35% conversion of HMF and a 96.8% yield of FDCA could be achieved at 1.48 V, with a faradaic efficiency as high as 84.47% in 1 M KOH electrolyte. More importantly, it also exhibits excellent stability for 10 cycles. The successful introduction of M 2+ vacancies was proved by electron paramagnetic resonance spectroscopy. X-ray photoelectron spectroscopy results confirmed that the implanted cationic vacancies would effectively raise the electron density of d-NiFe LDH and tailor the electronic structures of metal sites. This results in a significantly increased active site number and lowered charge transfer resistance that facilitate the electrocatalytic performance improvement. Postreaction characterization indicates that the in situ generated metal (oxy)hydroxides are the active species, and the HMF would be oxidized through both chemical and electrochemical pathways. These interesting findings shed light on the innovation of defect-rich catalysts and their promising application in electrochemical biomass derivative upgrading.

Fabricating effective non-precious metal-based catalysts for hydrogen production via electrochemical water splitting is of considerable importance but remains challenging. Transition metal nitrides possessing metallic character and corrosion resistance have been considered as potential replacements for precious metals. However, their activities for water electrolysis are impeded by the strong hydrogen adsorption and low water adsorption energies. Herein, V-doped bimetallic nitrides, V-FeNi3N/Ni3N heterostructure, are synthesized via a hydrothermal–nitridation protocol and used as electrocatalysts for water splitting and urea electrolysis. The V-FeNi3N/Ni3N electrode exhibits superior HER and OER activities, and the overpotentials are 62 and 230 mV to acquire a current density of 10 mA cm–2, respectively. Moreover, as a bifunctional electrocatalyst for overall water splitting, a two-electrode device needs a voltage of 1.54 V to reach a current density of 10 mA cm–2. The continuous electrolysis can be run for more than 120 h, surpassing most previously reported electrocatalysts. The excellent performance for water electrolysis is dominantly due to V-doping and interface engineering, which could enhance water adsorption and regulate the adsorption/desorption of intermediates species, thereby accelerating HER and OER kinetic processes. Besides, a urea-assisted two-electrode electrolyzer for electrolytic hydrogen production requires a cell voltage of 1.46 V at 10 mA cm–2, which is 80 mV lower than that of traditional water electrolysis.