Exploring earth-abundant electrocatalysts with Pt-like performance toward alkaline hydrogen evolution reaction (HER) is extremely desirable for the hydrogen economy but remains challenging. Herein, density functional theory (DFT) predictions reveal that the electronic structure and localized charge density at the heterointerface of NiP2–FeP2 can be significantly modulated upon coupling with metallic Cu, resulting in optimized proton adsorption energy and reduced barrier for water dissociation, synergistically boosting alkaline HER. Motivated by theoretical predictions, we developed a facile strategy to fabricate interface-rich NiP2–FeP2 coupled with Cu nanowires (CuNW) grown on Cu foam (NiP2–FeP2/CuNW/Cuf). Benefiting from the superior intrinsic activity, conductivity, and copious active sites, the obtained catalyst exhibited exceptional alkaline HER activity requiring a low overpotential of 23.6 mV at −10 mA/cm2, surpassing the state-of-the-art Pt. Additionally, a full electrolyzer required a cell voltage of 1.42/1.4 V at 10 mA/cm2 in alkaline water/seawater with promising stability. This work highlights a design principle for advanced HER catalysts and beyond.

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.

Seawater is the most plentiful natural resource we have on earth and new research looking for the alternative to the freshwater as seawater for hydrogen production by electrolysis. However, selective...