Discovering efficient and promising non-noble catalysts toward the alkaline hydrogen evolution reaction (HER) is vital for a clean energy system. Here, we design an efficient alkaline HER electrocatalyst, coating of WN nanowire core with a Ni­(OH)2 shell supported on a carbon fiber paper (WN-Ni­(OH)2). In a 1 M KOH solution, the hierarchical electrocatalyst affords a current density of 20 mA cm–2 at an overpotential of 170 mV and 100 mA cm–2 at 245 mV. The enhanced performance of WN-Ni­(OH)2 in the HER is attributed to the synergy between WN and Ni­(OH)2: during water dissociation, hydroxyl groups are preferentially adsorbed on WN and hydrogen on Ni­(OH)2; meanwhile, Ni­(OH)2 could promote hydroxyl group desorption from WN. Thus, the full-surface Volmer reaction kinetics could be enhanced. As a consequence, the WN-Ni­(OH)2 has a reduced activation energy of the HER and enhanced intrinsic activity performance. Meanwhile, the hybrid can reach a current density of 100 mA cm–2 at an overpotential of 339 mV for the oxygen evolution reaction (OER), and an overpotential of 510 mV for the full water-splitting reaction. This interfacial cooperation offers a promising bifunctional electrocatalyst, as well as a hopeful strategy for fabricating efficient nitride-based electrocatalysts in alkaline media.

2D hybrid perovskite ferroelectrics have drawn great attention in the field of photodetection, because the spontaneous polarization-induced built-in electric field can separate electron-hole pairs, and makes self-powered photodetection possible. However, most of the 2D hybrid perovskitebased photodetectors focused on the detection of visible light, and only a few reports realized the self-powered and sensitive ultraviolet (UV) detection using wide bandgap hybrid perovskites. Here, 2D ferroelectric PMA 2 PbCl 4 monocrystalline microbelt (MMB)-based PDs are demonstrated. By using the ferro-pyro-phototronic effect, the self-powered Ag/Bi/2D PMA 2 PbCl 4 MMB/Bi/Ag PDs show a high photoresponsivity up to 9 A/W under 320 nm laser illumination, which is much higher than those of previously reported self-powered UV PDs. Compared with responsivity induced by the photovoltaic effect, the responsivity induced by the ferro-pyro-phototronic effect is 128 times larger. The self-powered PD also shows fast response and recovery speed, with the rise time and fall time of 162 and 226 μs, respectively. More importantly, the 2D PMA 2 PbCl 4 MMB-based PDs with Bi/Ag electrode exhibit significant stability when subjected to high humidity, continuous laser illumination, and thermal conditions. Our findings would shed light on the ferro-pyro-phototronic-effect-based devices, and provide a good method for high-performance UV detection.

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Hydrogen generation from water-gas shift (WGS) reaction requires the import of secondary energy, making it unsuitable for large scale application. Herein, we present a new system composed by new photothermal...

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