Recent Advances and Perspectives in Ru Hybrid Electrocatalysts for the Hydrogen Evolution Reaction

The water-splitting reaction for green hydrogen generation requires highly efficient catalysts on the side for the hydrogen evolution reaction (HER), and metal ruthenium (Ru) is considered a promising catalyst as a result of its similar property in hydrogen-bonding ability but low cost compared to Pt-based materials. The performance is further boosted by the recently developed hybrid Ru-based electrocatalysts. To reveal the relationship between the hybrid catalyst systems and activity for Ru-based catalysts, the research progress of heterostructured Ru hybrid catalysts in the HER is reviewed in this effort. The enhancement of HER activity of Ru hybrid catalysts is first described on the basis of the synergistic effect, strain effect, and electronic effect, and then, the latest progress is discussed in three categories of single ruthenium catalysts, ruthenium-related compounds, and ruthenium alloy catalysts. It is concluded that the heterostructured interface engineering strategy plays an important role in enhancing the activity of Ru-based catalysts in the HER. In the end, the actual problems and challenges are discussed, e.g., the intrinsic activity and stability, application in the real device, etc. It is recommended to pay attention to the long-term stability, performance, and structural evolution as well as the application of the catalysts in the devices. It is hoped that this effort will help with understanding the progress of Ru-based hybrid catalysts in the field of HER catalysis.