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Highly active, ultra-long duration and cost-effective catalysts are imminently required for the development of electrolytic appliances for H2 generation. Herein, we propose a novel and facile strategy to fabricate P doped CoS2 nanosheet arrays on carbon cloth (Co-S-P/CC) as bifunctional electrocatalysts toward hybrid water electrolysis, in which the tardy anodic oxygen evolution reaction (OER) is substituted by a more favorable kinetic and thermodynamic ethanol oxidation reaction (EOR). Benefitting from the abundant active sites of Co-S-P nanosheets and the robust adhesion between Co-S-P and CC, the binder-free self-supported bifunctional Co-S-P/CC electrodes have satisfactory electrocatalytic activities and stabilities toward the EOR and hydrogen evolution reaction (HER). Notably, owing to the more favorable kinetics and thermodynamics of the EOR compared to those of the OER catalyzed by the Co-S-P/CC electrode, the required cell voltage for hybrid water electrolysis (1.63 V) is remarkably decreased compared to water electrolysis (1.77 V). Furthermore, the oxidation product acetic acid is more valuable than raw ethanol or oxygen from water splitting alone. This work may broaden the horizons in exploring and designing novel electrocatalysts, which can integrate the HER with other small organic molecule oxidation reactions for multifarious energy-related applications.

Urea electrolysis is an appealing energy conversion technology to produce hydrogen (H2) and alleviate the problem of urea-rich wastewater treatment concurrently. In particular, electrocatalytic performance can be dramatically enhanced by rationally modulating the surface charge distribution with a well-tuned heterostructure. Herein, a heterostructure is constructed by NiMoO4 nanosheets grown on an interior hollow NiS@Ni3S2 nanorods framework (NiS@Ni3S2/NiMoO4). Density functional theory (DFT) calculations demonstrate that the formed heterojunction structure leads to a tailored surface charge state of NiMoO4, with oxygen as the nucleophilic region and molybdenum as the electrophilic region, which facilitates the decomposition of urea molecules and thus significantly improves hydrogen evolution. As expected, the assembled NiS@Ni3S2/NiMoO4 system substantially expedites urea electrolysis activity with a cell voltage of 1.40 V at 10 mA cm−2, which is 200 mV less than the voltage of an overall water splitting system.

Urea electrolysis offers the prospect of cost-effective and energy-saving hydrogen production together with mitigating urea-rich wastewater pollution instead of overall water splitting. Hence, here, high-efficiency bifunctional electrocatalysts were developed for both the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) via the in situ vertical growth of thorny leaf-like (2D nanosheets supporting 1D nanowires) NiCoP on a carbon cloth (NiCoP/CC). After integrating the advantages of the synergistic effect between Ni and Co as well as the unique hierarchical structure combined with 1D nanowires, 2D nanosheets and a 3D conductive carbon cloth substrate, the electrode exhibited excellent electrocatalytic activity toward HER and UOR. The electrolytic cell assembled using NiCoP/CC as the anode and the cathode could provide current density of 10 mA cm−2 at a cell voltage of 1.42 V (160 mV less than that for its urea-free counterpart) as well as remarkable durability over 30 h. Thus, the cost-effectiveness and high activity of the NiCoP/CC electrode pave the way to explore transition metal-based electrocatalysts for urea electrolysis.

The production and storage of hydrogen are the two most critical challenges for hydrogen energy development. In addition, converting H2 from the as-obtained gas state to a stable storage state consumes excess energy and increases the practical cost of hydrogen fuel. Accordingly, we now present a simple hybrid material system (Co/TiO2) that efficiently synchronizes hydrogen photogeneration in water with its room-temperature storage. In the composite, through a series of carefully controlled experiments, ultrathin Co shells composed of 1, 2, 4, and 9 atom layers have been fabricated on TiO2 photocatalysts. Before saturation of hydrogen on metal Co, the hydrogen storage efficiency is close to 100%, meaning that nearly all hydrogen generated by photocatalytic water splitting is conserved. This work provides a new approach to combined structure-function design technology in the hydrogen energy field.

Hybridization of inorganic compounds with graphene-based materials can give rise to various enhanced properties, in which constructing a chemical bond stabilized hybrid structure is of primary importance. In this work, an archetypical hybrid material has been prepared by the reaction of an inorganic CoB noncrystal with graphene at room temperature with a high-energy ball-milling process. Experimental characterization results prove that the inorganic CoB noncrystal is stably pinned to graphene through B–C chemical bonds. The hybrid material shows a high electrochemical hydrogen storage capacity at room temperature. Based on the detailed experimental measurements and theory calculations, the enhanced electrochemical hydrogen storage ability is identified as a Kubas-enhanced hydrogen adsorption mechanism induced by the Co–B–C structure.