(Ni,Co)Se@Ni(OH)2 heterojunction nanosheets as an efficient electrocatalyst for the hydrogen evolution reaction

Ru doping and interface engineering synergistically boost the electrocatalytic performance of a WP/WP2 nanosheet array for an efficient hydrogen evolution reaction

The surface electronic structure and morphology of catalysts have a crucial impact on the electrocatalytic hydrogen evolution reaction performance. This work reports on the fabrication of a Ru-doped WP/WP2 heterojunction nanosheet array electrode via a one-step phosphating treatment of a Ru-doped WO3 precursor. Benefitting from the large electrochemical active surface of nanosheet arrays, rich WP/WP2 heterojunction interface, and trace Ru atom doping, the catalyst has a fairly low overpotential of 58.0 mV at 10 mA cm-2 and a Tafel slope of 50.71 mV dec-1 in acid solution toward the electrocatalytic HER. Further, theoretical calculations unveil that Ru atom doping and interface effect synergistically optimized the electronic structure of the catalyst and hence weakened the adsorption capacity of the catalyst surface toward hydrogen (H), which lowered the Gibbs free energy (ΔGH*) and consequently effectively improved the HER performance. This work may open new avenues for developing advanced nanoarray electrodes with efficient electrochemical energy conversion.

Ni3N/Co4N nanosheet heterojunction electrocatalyst for hydrogen evolution reaction in alkaline fresh water/simulated seawater

The Ni3N/Co4N nanosheet heterojunction exhibits higher HER activity in alkaline fresh water and simulated seawater.

Flower-like 1T-MoS2/NiCo2S4 on a carbon cloth substrate as an efficient electrocatalyst for the hydrogen evolution reaction

The 1T-MoS₂/NiCo₂S₄ composite in situ grown on carbon cloth (CC) was successfully prepared by a two-step hydrothermal method as an efficient electrode for the hydrogen evolution reaction. The morphology and composition characterization show that the composite has a flower-like structure with a large number of edges and surfaces exposed, and the content of the 1T phase in MoS₂ is 63%. 1T-MoS₂/NiCo₂S₄/CC exhibits an overpotential of 107 mV at 10 mA cm^-2, and a Tafel slope of 66.4 mV dec^-1 in an alkaline electrolyte. After continuous electrolysis for 24 h at an overpotential of 170 mV, 86% of the original current density was retained in an chronoamperometry measurement. The outstanding catalytic performance of the composite is ascribed to its unique structure, high 1T-MoS₂ content and the synergistic catalysis between 1T-MoS₂ and NiCo₂S₄. This work provides a facile and effective strategy for fabricating the 1T-MoS₂/NiCo₂S₄/CC composite and demonstrates that the composite is expected to be a competitive non-noble HER catalyst.

2D coordination polymer-derived CoSe2-NiSe2/CN nanosheets: the dual-phase synergistic effect and ultrathin structure to enhance the hydrogen evolution reaction

The evolution of cost-effective hydrogen evolution reaction (HER) electrocatalysts is of great significance for the development of clean energy. Exploring effective synthesis strategies to optimize the performance of non-noble metal electrocatalysts has always attracted our attention. Herein, ultrathin coordination polymers were used as precursors to controllably synthesize two-dimensional (2D) ultrathin dual-phase transition metal selenide (TMSs)/carbon-nitrogen (CN) composites (CoSe2-NiSe2/CN) by a two-step method (first a low temperature hydrothermal method for selenization, and then high temperature calcination selenization). Benefiting from its large specific surface area (49 m2 g-1), abundant catalytically active sites and synergistic effects, CoSe2-NiSe2/CN can significantly enhance the HER catalytic activity and exhibits good electrocatalytic activity with an overpotential of 150 mV at -10 mA cm-2, and a small Tafel slope of 42 mV dec-1 in an acidic electrolyte for the HER. This work provides a new strategy for optimizing the HER catalytic activity of TMSs by preparing 2D ultrathin dual-phase TMS composite materials.