Highly efficient pH-universal hydrogen evolution reaction catalyzed by rapidly reconstructed bimetallic cobalt-molybdenum alloy cuboids arrays

Given the inherent potential of seawater, industrial wastewater, and residential water as inherent feedstocks for hydrogen production through water electrolysis, there is a critical demand for the exploration of robust and stable hydrogen-evolving catalysts that can operate effectively across a diverse range of pH conditions. However, the pursuit of hydrogen-evolving electrocatalysts that demonstrate both good stability and high efficiency over a wide pH range remains a formidable challenge. Here we report the rational design and synthesis of an outstanding nanoporous hybrid electrocatalyst consisting of intermetallic cobalt-molybdenum alloy particles anchoring on MoO₂ cuboid arrays, which demands very low overpotentials of 72, 123 and 134 mV to deliver a current density of -100 mA cm^-2 for hydrogen evolution reaction under alkaline, neutral and acidic conditions, respectively. These catalytic activities are superior to most non-precious pure non-precious-metal-based catalysts documented in the literatures, and are even comparable to noble metal catalysts. In particular, this alloy electrocatalyst exhibits excellent stability at 50 or 300 mA cm^-2 without obvious activity degradation, which is further supported by the undetectable changes in the surface chemical valence states on the basis of in-situ X-ray photoelectron spectroscopic studies. This study provides an innovative strategy for the design and synthesis of effective non-noble intermetallic catalysts for pH-universal hydrogen evolution over a wide pH range.