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FeCo2O4 is a potential OER catalyst, but its catalytic activity still needs to be further improved due to its poor electrical conductivity and low material utilization. In this paper, we construct oxygen-vacancy-rich two dimensional FeCo2O4 nanosheet materials using a liquid-phase reduction strategy. Benefiting from its large specific surface area, numerous surface catalytic sites, enhanced electrical conductivity, and modulated electronic structure, the catalyst exhibits an overpotential of only 270 mV at a current density of 10 mA cm−2, which is lower than that of the original FeCo2O4 nanosheets (420 mV). At the same time, the catalyst can run steadily for 20 hours without obvious decay. [ABSTRACT FROM AUTHOR]

Hydrazine-assisted electrochemical water splitting is an important avenue toward low cost and sustainable hydrogen production, which can significantly reduce the voltage of electrochemical water splitting. Herein, we took a simple approach to fabricate NiFeP nanosheet arrays on nickel foam (NiFeP/NF), which exhibit superior electrocatalytic activity for the hydrogen evolution reaction (HER) and the hydrazine oxidation reaction (HzOR). Our investigations revealed that the excellent electrocatalytic activity of NiFeP/NF mainly arises from the bimetallic synergistic effect, abundant electrocatalytically active sites facilitated by the porous nanosheet morphology, high intrinsic conductivity of NiFeP/NF and strong NiFeP–NF adhesion. We assembled a hydrazine-boosted electrochemical water splitting cell using NiFeP/NF as a bifunctional catalyst for both electrodes, and the overall hydrazine splitting (OHzS) exhibits a considerably low overpotential (100 mV at 10 mA cm−2), and is stable for 40 h continuous electrolysis in a 1 M KOH + 0.5 M N2H4 electrolyte. When it is applied to hydrogen production by seawater electrolysis, its catalytic activity shows strong tolerance. This work provides a promising approach for low cost, high-efficiency and stable hydrogen production based on hydrazine-assisted electrolytic seawater splitting for future applications. [ABSTRACT FROM AUTHOR]

Finding effective and affordable non-noble metal catalysts is one of the most important yet difficult tasks because of the sluggish kinetics of the oxygen evolution reaction (OER). Therefore, we synthesized vanadium-doped CoFe PBA nanosheets on nickel foam in a single step to change the electronic structure with metal doping. The sheet structure facilitates charge transfer, while vanadium doping modifies the electronic structure to enhance the catalytic activity. With just a 229 mV overpotential needed in the OER reaction to reach 10 mA cm−2, the as-synthesised electrocatalyst demonstrates high electrocatalytic activity. The produced electrocatalyst can operate at a current density of 10 mA cm−2 for 12 h, and it displays outstanding stability even at a high OER current density of 100 mA cm−2 for 12 h. This study will contribute to the development of efficient and affordable non-noble metal-based electrocatalysts. [ABSTRACT FROM AUTHOR]

The exploration of efficient, stable, and economical electrocatalysts for oxygen evolution reaction (OER) is of great significance and challenge for the development of renewable energy. A series of Ni-based layered double hydroxides (LDHs) have been explored as promising electrocatalysts for OER on account of their earth abundance, low overpotential, and super stability. However, the low electrical conductivity of LDHs cannot satisfy the progressive requirements of water splitting. Herein, we introduce a template strategy to synthesize trimetallic nickel-chromium LDH–cobalt (NiCr-LDH–Co) nanosheets on nickel foam (NiCr-LDH–Co/NF) without any binders as efficient catalysts for OER. Compared with the reported NiCoCr-LDHs synthesized by one-step, our NiCr-LDH–Co/NF delivered a lower overpotential of 229.4 mV at 50 mA cm−2, which is even lower than that of all the reported bimetallic nickel-based LDHs (NiFe-LDH, NiCo-LDH, NiMn-LDH, NiTi-LDH, NiV-LDH, etc.) and the precious RuO2 catalyst. Furthermore, the NiCr-LDH–Co/NF was maintained for at least 24 h at a high current density of 50 mA cm−2 without much deviation in 1 M KOH solution. The effective integration of the layered structures of LDH and the high electronic conductivity of the Co element endow NiCr-LDH–Co/NF remarkable catalytic ability for the OER process. Furthermore, the strategy expands the possibility for improving the catalytic activity of trimetallic LDHs as OER catalysts. [ABSTRACT FROM AUTHOR]

Constructing a heterostructure is an efficient strategy to enhance the catalytic activity toward the oxygen evolution reaction (OER). Herein, Ce-modified Ni(OH)2 nanoparticles are anchored on Ni-MOF nanosheets by the electrodeposition strategy, forming a self-supporting electrode of Ce-m-Ni(OH)2@Ni-MOF. The Raman spectrum proves that both Ce(OH)3 and Ce doping exist in Ce-modified Ni(OH)2 nanoparticles. The heterostructure possesses an open nanosheet structure, with a good interaction between Ni-MOF and Ce-m-Ni(OH)2, which enables efficient mass/charge transfer and the synergetic effect between Ni and Ce, leading to a high-performance electrocatalyst. Specifically, Ce-m-Ni(OH)2@Ni-MOF achieves current densities of 50 and 100 mA cm−2 at low overpotentials of 219 and 272 mV, respectively, and retains high activity for at least 30 h. [ABSTRACT FROM AUTHOR]