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New oxygen evolution reaction (OER) electrocatalysts based on low‐cost elements, which set new benchmark levels of activity, are vital if water electrolysis is to be applied on a global scale. Herein, a low‐cost bimetallic phospho‐boride catalyst was developed that showed outstanding OER activity of approximately 195 mV to achieve 10 mA cm−2 in alkaline water electrolysis, with a minimal catalyst loading of 0.3 mg cm−2. The contrasting electron transfer property of the metal borides and phosphides when combined in phospho‐boride modulated the electron density of the Co atom, yielding highly active CoOOH species at lower potentials. The addition of Mo at low levels further enhanced the activity by increasing the surface area and by formation of nano‐crystalline domains. The combined contributions from each of the components resulted in a new benchmark mass activity of 666 A g−1 at 300 mV overpotential. This work presents a new avenue towards fabricating electrode materials with exceptional performances.

Three different hierarchical nanostructured Co3O4 catalysts are prepared by simple alteration of the precursor. The Co3O4–S catalyst shows superior water oxidation activity due to its improved charge transfer ability and high specific surface area.

Amorphous materials are used in multitude of catalytic applications, including electrocatalytic water-splitting. Identification and investigation of active sites in amorphous catalysts are rarely reported, mainly owing to the complexity of the systems. Herein, we report an amorphous bifunctional Co–W–B electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The optimized Co–W–B catalyst showed promising overpotential values of 97 mV (HER) and 292 mV (OER), respectively, to achieve 10 mA cm–2 in 1 M KOH, with good stability. The promoting effect of W in Co–B was investigated experimentally, while computational tools were used to identify all the possible catalytic sites in an amorphous Co–W–B model and classify the most preferred sites for HER and OER. The presence of multi-catalytic sites with specific selectivity toward HER and OER was observed, which explained the bifunctional activity of Co–W–B. This study will foster better understanding of the origin of catalytic activity in similar amorphous systems.