To engineer low-cost, high-efficiency, and stable oxygen evolution reaction (OER) catalysts, structure effects should be primarily understood. Focusing on this, we systematically investigated the relationship between structures of materials and their OER performances by taking four 2D α-Ni(OH) as model materials, including layer-stacked bud-like Ni(OH)-NB, flower-like Ni(OH)-NF, and petal-like Ni(OH)-NP as well as the ultralarge sheet-like Ni(OH)-NS. For the first three (layer-stacking) catalysts, with the decrease of stacked layers, their accessible surface areas, abilities to adsorb OH, diffusion properties, and the intrinsic activities of active sites increase, which accounts for their steadily enhanced activity. As expected, Ni(OH)-NP shows the lowest overpotential (260 mV at 10 mA cm) and Tafel slope (78.6 mV dec) with a robust stability over 10 h among the samples, which also outperforms the benchmark IrO (360 mV and 115.8 mV dec) catalyst. Interestingly, Ni(OH)-NS relative to Ni(OH)-NP exhibits even faster substance diffusion due to the sheet-like structure, but shows inferior OER activity, which is mainly because the Ni(OH)-NP with a smaller size possesses more active boundary sites (higher reactivity of active sites) than Ni(OH)-NS, considering the adsorption properties and accessible surface areas of the two samples are quite similar. By comparing the different structures and their OER behaviors of four α-Ni(OH) samples, our work may shed some light on the structure effect of 2D materials and accelerate the development of efficient OER catalysts.

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The development of designing and searching inexpensive electrocatalysts with high activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant to enable water splitting as a future renewable energy source. Herein, we synthesize a new CoP­(MoP)-CoMoO3 heterostructure coated by a N-doped carbon shell [CoP­(MoP)-CoMoO3@CN] via thermal decomposition and phosphatizing of the CoMoO4·0.9H2O nanowires encapsulated in N-doped carbon. At 10 mA·cm–2, this CoP­(MoP)-CoMoO3@CN nanocomposite exhibits superior electrocatalytic activity at low overpotentials of 296 mV for OER and 198 mV for HER in alkaline media. More importantly, we achieve a current density of 10 mA·cm–2 at 1.55 V by using this CoP­(MoP)-CoMoO3@CN as both cathode and anode for overall water splitting. This promising performance could be due to the high activity of CoP­(MoP)-CoMoO3 and the good conductivity of the external mesoporous N-carbon shell, which makes the CoP­(MoP)-CoMoO3@CN nanowires a competitive alternative to noble-metal-based catalysts for water splitting.

Bimetallic thin film NiCo–NiCoO2@NC exhibits a synergy of two active metals – Ni and Co, achieving excellent activity for both the HER and OER.

The instable structure of Pt-based high-indexed facets (HIFs) facile reconstructed is a key obstacle for further practical applications because of its high surface energy and amounts of undercoordinated surface atoms. Herein, a strategy to advance the fundamental surface study on Pt-based HIFs materials is addressed by implanting non-noble metal or nonmetals as “active auxiliaries” into the near-surface of noble metal nanocrystals bounded with HIFs to engineer a stable structured catalyst. Then the Mo/Pt3Mn catalysts serving as proof-of-concept examples are designed and show enhanced catalytic performance of ethylene glycol (EG). According to the electrochemical in situ Fourier transform infrared spectroscopy results, the Mo modified Pt3Mn alloys with HIFs promote not only the C–C cleavage of EG but also the direct conversion of COHX to CO2, without the formation of COL poison species. In this case, the Mo/Pt3Mn catalysts show the greatly significant increase of the catalytic activity in copamprison with Pt3Mn CNC and the commercial Pt/C, as well as the enhanced stability. The high-resolution transmission electron microscopy and X-ray photoelectron spectrum assisted by Ar surface etching experiments accompanied by density functional theory calculations are further used to explore the structure–performance relationship of Mo/Pt3Mn CNC for electro-oxidation of EG. This study addresses a promising strategy to fabricate a stable structured catalysts, which will elucidate a very promising methodology for developing Pt-based catalysts for further application of the fuel cell.