Ruthenium clusters decorated on lattice expanded hematite FeO for efficient electrocatalytic alkaline water splitting.

Electrocatalytic water splitting in alkaline media plays an important role in hydrogen production technology. Normally, the catalytic activity of commonly used transition metal oxides usually suffers from unsatisfactory electron conductivity and unfavorable binding strength for transition intermediates. To boost the intrinsic catalytic activity, we propose a rational strategy to construct lattice distorted transition metal oxides decorated with noble-metal nanoclusters. This strategy is verified by loading ruthenium clusters onto lithium ion intercalated hematite FeO, which leads to significant distortion of the FeO unit cells. A remarkable overpotential of 21 mV with a Tafel slope of 39.8 mV dec is achieved at 10 mA cm for the hydrogen evolution reaction in 1.0 M KOH aqueous electrolyte. The assembled alkaline electrolyzer can catalyse overall water splitting for as long as 165 h at a current density of 250 mA cm with negligible performance degradation, indicating great potential in the field of sustainable hydrogen production.