Green hydrogen can be produced through water electrolysis, with alkaline water electrolysers being particularly advantageous among the available technologies. Alkaline water electrolysers can use cost-effective, non-noble metal catalysts owing to their less acidic operating environment, making large-scale hydrogen production more economical. However, they have some drawbacks, including challenges in reaching high current densities and achieving energy efficiency, both of which are necessary for effective large-scale hydrogen production. Now, writing in Nature Communications, Yan Shen, Chuan Zhao, Mingkui Wang and colleagues present an efficient electrocatalyst that maintains high stability even while operating at high current densities.

NiMo alloy-based catalysts have shown promise for their strong water dissociation ability and effective hydrogen adsorption, which are beneficial for the HER. However, optimizing the adsorption and desorption of HER intermediates remains challenging, which affects the intrinsic activity of these catalysts under high current densities. Combining NiMo with MoO2 further improves performance, but this heterostructure is limited by the poor conductivity of MoO2.