Single-atom-catalysts (SACs) afford a fascinating activity with respect to other nanomaterials for hydrogen evolution reaction (HER), yet the simplicity of single-atom center limits its further modification and utilization. Obtaining bimetallic single-atom-dimer (SAD) structures can reform the electronic structure of SACs with added atomic-level synergistic effect, further improving HER kinetics beyond SACs. However, the synthesis and identification of such SAD structure remains conceptually challenging. Herein, systematic first-principle screening reveals that the synergistic interaction at the NiCo-SAD atomic interface can upshift the d-band center, thereby, facilitate rapid water-dissociation and optimal proton adsorption, accelerating alkaline/acidic HER kinetics. Inspired by theoretical predictions, we develop a facile strategy to obtain NiCo-SAD on N-doped carbon (NiCo-SAD-NC) via in-situ trapping of metal ions followed by pyrolysis with precisely controlled N-moieties. X-ray absorption spectroscopy indicates the emergence of Ni-Co coordination at the atomic-level. The obtained NiCo-SAD-NC exhibits exceptional pH-universal HER-activity, demanding only 54.7 and 61 mV overpotentials at −10 mA cm⁻² in acidic and alkaline media, respectively. This work provides a facile synthetic strategy for SAD catalysts and sheds light on the fundamentals of structure-activity relationships for future applications.

The poor catalyst stability in acidic oxidation evolution reaction (OER) has been a long-time issue. Herein, we introduce electron-deficient metal on semiconducting metal oxides-consisting of Ir (Rh, Au, Ru)-MoO₃ embedded by graphitic carbon layers (IMO) using an electrospinning method. We systematically investigate IMO’s structure, electron transfer behaviors, and OER catalytic performance by combining experimental and theoretical studies. Remarkably, IMO with an electron-deficient metal surface (Ir^x+; x > 4) exhibit a low overpotential of only ~156 mV at 10 mA cm⁻² and excellent durability in acidic media due to the high oxidation state of metal on MoO₃. Furthermore, the proton dissociation pathway is suggested via surface oxygen serving as proton acceptors. This study suggests high stability with high catalytic performance in these materials by creating electron-deficient surfaces and provides a general, unique strategy for guiding the design of other metal-semiconductor nanocatalysts.

Tensile-strain introduced on the surface of oxide support via liquid nitrogen quenching method stabilized ultra-high loading of single metal atom site for exceptional urea electrolysis.

Highly efficient electrocatalysts for water splitting generally involve noble metals (Pt, Ir, Ru, etc.) or expensive transition metals (Ni, Co, Cu, etc.), which have hindered their widespread application. Here, we report a brand-new, low-cost phosphated Zn-doped bimetallic (Fe/Mn) skeleton (Zn-Fe/Mn@Mn-FeP, FMZP4) with genuine potential as a highly effective water-splitting electrocatalyst. Benefiting from heterogeneous atom doping as well as a self-supported electrode composed of a porous Zn-Fe/Mn skeleton and in situ grown phosphides (Mn-FeP) with a hierarchical ultrathin nanosheet structure, which provide rapid electron transport and efficient mass transport channels, the optimized FMZP4 exhibits low overpotentials of 53 mV and 184 mV to reach current densities of 10 mA cm⁻² (η₁₀) and 20 mA cm⁻² (η₂₀₎ for hydrogen and oxygen evolution reactions, respectively, revealing good stability in a long potential cycling test (1000 cycles) and remaining completely stable over an 80 h galvanostatic measurement at 10/50 mA cm⁻². More impressively, it needs just 1.79 V to achieve η₅₀ for full water splitting in an alkaline electrolyte and exhibits superior electrochemical durability. The excellent electrocatalytic activity makes it a candidate material for a low-cost electrocatalyst with broad applicability in water splitting.