In situ evolved NiMo/NiMoO₄ nanorods as a bifunctional catalyst for overall water splitting

Due to their good conductivity and catalytic performance, Ni—Mo-based catalysts are well-established for highly effective water splitting. However, the know-how required to fabricate distinct interfaces and electronic structures for metal oxides is still a challenge, and the synergistic effect between metal and metal oxides that enhances electrocatalytic activity is still ambiguous. As described here, by controlling the lithium-induced conversion reaction of metal oxides, metal/metal-oxide composites with plentiful interfaces and prominent electrical interconnections were fabricated, which can boost active sites and accelerate mass transfer during electrocatalytic reactions. As a consequence, the superior catalytic activity of ECT-NiMo/NiMoO₄ exhibited a low overpotential of 61 mV at a current density of 10 mA cm⁻² for the hydrogen evolution reaction and 331 mV at 100 mA cm⁻² for the oxygen evolution reaction. When integrated into a two-electrode system, the ECT-NiMo/NiMoO₄ revealed a highly stable and efficient performance in overall water splitting. This work provides a promising approach to enhance the metallicity and electron redistribution of catalysts for numerous water-splitting applications and many other possibilities for energy storage devices. (paper)