Recent advances in ruthenium-based electrocatalysts for the hydrogen evolution reaction

Exploration of electrocatalysts for clean and sustainable hydrogen generation from water splitting has received huge attention due to the depletion of fossil fuels and environmental pollution. Although platinum (Pt) is the most efficient catalyst for the hydrogen evolution reaction (HER), it has limitations for widespread applications due to its towering cost, scarcity and instability. Various catalysts such as precious/non-precious metal and metal-free catalysts have been developed for a viable HER process. Among them, ruthenium (Ru) based catalysts, which possess appropriate hydrogen bonding energy and reasonable price, have demonstrated strong potential as an alternative to Pt for the HER. In this review article, we summarize recently developed Ru-based electrocatalysts with superior HER performance, i.e., Ru on carbon supports, Ru phosphide based catalysts, and Ru coupled with transition metals. Finally, we discuss the challenges and perspectives of Ru-based catalysts in the HER research field.