Herein, ruthenium (Ru) and iridium (Ir) are introduced to tailor the atomic and electronic structure of self-supported nickel-vanadium (NiV) layered double hydroxide to accelerate water splitting kinetics, and the origin of high hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities are analyzed at atomic level. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectroscopy studies reveal synergistic electronic interactions among Ni, V, and Ru (Ir) cations. Raman spectra and Fourier and wavelet transform analyses of the extended X-ray absorption fine structure indicate modulated local coordination environments around the Ni and V cations, and the existence of V vacancies. The Debye–Waller factor suggests a severely distorted octahedral V environment caused by the incorporation of Ru and Ir. Theoretical calculations further confirm that Ru or Ir doping could optimize the adsorption energy of intermediates in the Volmer and Heyrovsky steps for HER and accelerate the whole kinetic process for OER.

The development of low-cost, high-efficiency, and stable bifunctional electrocatalysts toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of paramount importance for large-scale water splitting. Here, we develop a new strategy for the first design and synthesis of a NiO@Ni decorated WS₂ nanosheet array on carbon cloth (NiO@Ni/WS₂/CC) composite. This composite serves as a unique three-dimensional (3D) synergistic electrocatalyst that not only combines the intrinsic properties of individual NiO@Ni and WS₂, but also exhibits significantly improved HER and OER activities when compared to that of pure NiO@Ni and WS₂. This electrocatalyst possesses Pt-like activity for HER and exhibits better OER performance than that for commercial RuO₂, as well as demonstrating superior long-term durability in alkaline media. Furthermore, it enables an alkaline electrolyzer with a current density of 10 mA cm^–2 at a cell voltage as 1.42 V, which is the lowest one among all reported values to date. The excellent performance is mainly attributed to the unique 3D configuration and multicomponent synergies among NiO, Ni, and WS₂. Our findings provide a new idea to design advanced bifunctional catalysts for water splitting.

Ru, RuO₂, and MoO₃embedded carbon nanorods with superior HER performance were synthesized through electrospinning and subsequent calcination.

Owing to the unique structure and synergistic effect between MoNi and CoMoO₃, the MoNi/CoMoO₃/NF exhibits high hydrogen evolution activity which requires a low overpotential of only 18 mV to deliver a current density of 10 mA cm⁻².