Nanostructured Ni-Cu Electrocatalysts for the Oxygen Evolution Reaction

Transition metal-based electrocatalysts for alkaline overall water splitting: advancements, challenges, and perspectives

Water electrolysis is a promising method for efficiently producing hydrogen and oxygen, crucial for renewable energy conversion and fuel cell technologies. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are two key electrocatalytic reactions occurring during water splitting, necessitating the development of active, stable, and low-cost electrocatalysts. Transition metal (TM)-based electrocatalysts, spanning noble metals and TM oxides, phosphides, nitrides, carbides, borides, chalcogenides, and dichalcogenides, have garnered significant attention due to their outstanding characteristics, including high electronic conductivity, tunable valence electron configuration, high stability, and cost-effectiveness. This timely review discusses developments in TM-based electrocatalysts for the HER and OER in alkaline media in the last 10 years, revealing that the exposure of more accessible surface-active sites, specific electronic effects, and string effects are essential for the development of efficient electrocatalysts towards electrochemical water splitting application. This comprehensive review serves as a guide for designing and constructing state-of-the-art, high-performance bifunctional electrocatalysts based on TMs, particularly for applications in water splitting.

Nanoflower-like FeVNi3S2-xas efficient electrocatalyst for alkaline oxygen evolution reaction

The development of low cost efficient catalysts for oxygen evolution reaction (OER) is still a obstacle to realize the commercialization of electrocatalytic water splitting. Herein, interface engineering and heteroatom doping is adopted to synthesize iron and vanadium doped nickel sulfide on nickel foam via hydrothermal method followed by hydrogen treatment to create sulfur defects. The optimized nanoflower-like FeVNi3S2-x/NF is an efficient OER electrocatalyst that outperforms many of the reported transition metals catalysts. Benefiting from abundant sulfur defects and the synergistic effect of heteroatom doping, FeVNi3S2-x/NF exhibits an ultralow overpotential of 230 mV to reach a current density of 100 mA cm-2, a rapid reaction kinetics with a small Tafel slope of 46.6 mV dec-1, and a stable long-term durability in 1 M KOH. Experimental results and characterizations confirm that sulfur vacancies together with the synergistic effect from multiple heteroatom doping can effectively regulate the electronic structure, resulting in increased electrical conductivity and electrochemically active surface area, thus enhancing OER performance. Furthermore,in situRaman spectroscopy reveals that, the reconstitution amorphous nickel oxyhydroxide (NiOOH) on the catalyst surface is responsible for catalyzing the OER reaction. This work represents a promising methodology to synthesize low-cost and highly active OER electrocatalysts.

Iron-modulated Ni3S2 derived from a Ni-MOF-based Prussian blue analogue for a highly efficient oxygen evolution reaction

Developing efficient, environmentally friendly and cost-effective non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is essential to alleviate the energy crisis and environmental pollution.

Recent Progress in the Development of Advanced Functionalized Electrodes for Oxygen Evolution Reaction: An Overview

Presently, the global energy demand for increasing clean and green energy consumption lies in the development of low-cost, sustainable, economically viable and eco-friendly natured electrochemical conversion process, which is a significant advancement in different morphological types of advanced electrocatalysts to promote their electrocatalytic properties. Herein, we overviewed the recent advancements in oxygen evolution reactions (OERs), including easy electrode fabrication and significant action in water-splitting devices. To date, various synthetic approaches and modern characterization techniques have effectively been anticipated for upgraded OER activity. Moreover, the discussed electrode catalysts have emerged as the most hopeful constituents and received massive appreciation in OER with low overpotential and long-term cyclic stability. This review article broadly confers the recent progress research in OER, the general mechanistic approaches, challenges to enhance the catalytic performances and future directions for the scientific community.

Nanostructured RuO2-Co3O4@RuCo-EO with low Ru loading as a high-efficiency electrochemical oxygen evolution catalyst

Electrochemical water splitting technology is considered to be the most reliable method for converting renewable energy such as wind and solar energy into hydrogen. Here, a nanostructured RuO₂/Co₃O₄–RuCo-EO electrode is designed via magnetron sputtering combined with electrochemical oxidation for the oxygen evolution reaction (OER) in an alkaline medium. The optimized RuO₂/Co₃O₄–RuCo-EO electrode with a Ru loading of 0.064 mg cm⁻² exhibits excellent electrocatalytic performance with a low overpotential of 220 mV at the current density of 10 mA cm⁻² and a low Tafel slope of 59.9 mV dec⁻¹ for the OER. Compared with RuO₂ prepared by thermal decomposition, its overpotential is reduced by 82 mV. Meanwhile, compared with RuO₂ prepared by magnetron sputtering, the overpotential is also reduced by 74 mV. Furthermore, compared with the RuO₂/Ru with core–shell structure (η = 244 mV), the overpotential is still decreased by 24 mV. Therefore, the RuO₂/Co₃O₄–RuCo-EO electrode has excellent OER activity. There are two reasons for the improvement of the OER activity. On the one hand, the core–shell structure is conducive to electron transport, and on the other hand, the addition of Co adjusts the electronic structure of Ru.

The optimized RuO₂/Co₃O₄–RuCo-EO electrode with Ru loading of 0.064 mg cm⁻² exhibits the excellent oxygen evolution activity with an overpotential of 220 mV at the current density of 10 mA cm⁻² and a Tafel slope of 59.9 mV dec⁻¹.

NixCu1−x/CuO/Ni(OH)2 as highly active and stable electrocatalysts for oxygen evolution reaction

Ni–Cu alloy-based nanomaterials are representative cost-effective materials that have been widely used as highly active and stable electrocatalysts for electrochemical energy applications, such as the water oxidation reaction, the methanol/ethanol reaction and many other small molecule oxidation reactions.