A sea-change: manganese doped nickel/nickel oxide electrocatalysts for hydrogen generation from seawater

The practical implementation of electrolytic water splitting systems (especially those powered by renewable energy resources, such as solar and wind) requires active and stable catalysts for the hydrogen evolution reaction (HER). The development of catalysts that can compete with, or exceed, the performance of the exorbitant platinum (Pt)-based benchmark is highly desirable. Here, we demonstrate the development of a highly active HER catalyst electrode, exhibiting Pt-like performances in both neutral electrolytes and natural seawater. The catalyst was obtained by pyrolysing a manganese-based metal organic framework (Mn-MOF) on nickel foam (Ni-F). We discovered for the first time that nickel foam not only acts as the substrate for catalyst growth but also provides nickel species that interact with the Mn-MOF, resulting in the formation of Mn doped nickel oxide/nickel hetero-structures on Ni-F (Mn–NiO–Ni/Ni-F). The potential utilization of this catalyst electrode for commercial applications was demonstrated in a self-customized water electrolyzer pack powered by photovoltaic cells.