Fe‐based oxides have been seldom reported as electrocatalysts for the hydrogen evolution reaction (HER), limited by their weak intrinsic activity and conductivity. Herein, phosphorus doping modulation is used to construct inverse spinel P‐Fe3O4 with dual active sites supported on iron foam (P‐Fe3O4/IF) for alkaline HER with an extremely low overpotential of 138 mV at 100 mA cm−2. The obtained inverse spinel Fe–O–P derived from controllable phosphorization can provide an octahedral Fe site and O atom, which bring about the unusual dissociation mechanisms of two water molecules to greatly accelerate the proton supply in alkaline media. Meanwhile, the ΔGH of the P atom in Fe–O–P as an active site is theoretically calculated to be 0.01 eV. Notably, the NiFe LDH/IF(+)||P‐Fe3O4/IF(−) couple achieves an onset potential of 1.47 V (vs RHE) for overall water splitting, with excellent stability for more than 1000 h at a current density of 1000 mA cm−2, and even for 25 000 s at 10 000 mA cm−2 in 6.0 m KOH at 60 °C. The excellent catalyst stability and low‐cost merits of P‐Fe3O4/IF may hold promise for industrial hydrogen production. This work may reveal a new design strategy of earth‐abundant materials for large‐scale water splitting.

A series of novel ordered hierarchically micro-and mesoporous Fe−N x -embedded graphitic architectures (Fe−N−GC) are directly prepared by the simple pyrolysis of the different nitrogen heterocyclic compounds and iron chlorides in the confined mesochannels of SBA-15. Among these porous Fe−N−GC materials, the sample prepared by heating 2,2-bipyridine and Fe chelates at 900 °C shows the more positive ORR onset potential and half-wave potential (E 1/2) values than commercial Pt−C catalysts in 0.1 M KOH, which illustrate that it is one of the most-promising nonprecious metal catalysts (NPMCs) among the reported NMPCs in alkaline medium. Moreover, unlike nitrogen-doped carbons and Co 3 O 4 /carbon composites, high ORR current density (5.2 mA cm −2 , 0.6 V) over this Fe−N−GC electrode with catalyst loading of 0.6 mg cm −2 can be also obtained in 0.1 M HClO 4 acidic solution, which is about 0.6 mA cm −2 larger than that over the electrode of commercial Pt/C with 20 μg Pt cm −2 loading. In addition, the effective embedding of active moieties in the graphitic frameworks and a direct four-electron reduction pathway in ORR contributes to its high durability in both alkaline and acidic media. Its excellent ORR activity should be ascribed to the optimized balance between active site density and capability for mass and charge transport. Such hierarchically porous Fe−N x −graphitic materials hold great promise for the practical utilization in cathode catalyst layers of proton exchange membrane fuel cells.

NiSe@NiOOH core-shell hyacinth-like nanostructures supported on nickel foam (NF) have been successfully synthesized by a facile solvothermal selenization and subsequent in situ electrochemical oxidation (ISEO). First, the unique NiSe/NF nanopillar arrays were prepared in N,N-dimethylformamide (DMF) as a precursor template that can provide a large surface area, excellent conductivity, and robust support. Next, amorphous NiOOH covering the surface of NiSe nanopillars was fabricated by ISEO, as confirmed by XPS andEDX spectroscopy. SEM images revealed the hyacinth-like morphology of NiSe@NiOOH/NF with NiOOH as the shell and NiSe as the core. The electrochemical performance of NiSe@NiOOH/NF for the oxygen evolution reaction (OER) was investigated. NiSe@NiOOH/NF demonstrates an obviously enhanced OER activity with much lower overpotential of 332 mV at 50 mA cm(-2) compared to other Ni-based electrocatalysts. The low charge-transfer resistance (Rct), large electrochemical double-layer capacitance (Cdl) of electrochemically active surface areas (ECSAs), and excellent long-term stability of NiSe@NiOOH/NF confirm the enhancement of its electrochemical performance for the OER, which can be ascribed to the large amount of active sites derived from the amorphous NiOOH shell and the good conductivity and stability derived from the NiSe core. In addition, the synergistic effect between the NiSe core and NiOOH shell could serve for a highly efficient OER electrocatalyst.

A facile two-step method has been used to synthesize binary Ni–Fe sulfides supported on nickel foam (NF) as electrocatalysts for the oxygen evolution reaction (OER).

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The design of electrocatalysts including precious and nonprecious metals for the hydrogen evolution reaction (HER) in alkaline media remains challenging due to the sluggish reaction kinetics caused by the additional water dissociation step.

Synthesis of Ag doped Co3O4 with different atomic ratios of Co2+/Co3+ and investigation of the effect of preferential exposure of Co2+ in Co3O4 on the acidic OER.

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