Ruthenium Oxide Nanosheets for Enhanced Oxygen Evolution Catalysis in Acidic Medium

The fabrication of highly active and robust hexagonal ruthenium oxide nanosheets for the electrocatalytic oxygen evolution reaction (OER) in an acidic environment is reported. The ruthenate nanosheets exhibit the best OER activity of all solution‐processed acid medium electrocatalysts reported to date, reaching 10 mA cm^?2 at an overpotential of only ≈255 mV. The nanosheets also demonstrate robustness under harsh oxidizing conditions. Theoretical calculations give insights into the OER mechanism and reveal that the edges are the origin of the high OER activity of the nanosheets. Moreover, the post OER analyses indicate, apart from coarsening, no observable change in the morphology of the nanosheets or oxidation states of ruthenium during the electrocatalytic process. Therefore, the present investigation suggests that ruthenate nanosheets are a promising acid medium OER catalyst with application potential in proton exchange membrane electrolyzers and beyond.     

Recent Progress on Multimetal Oxide Catalysts for the Oxygen Evolution Reaction

Hydrogen is a promising alternative fuel for efficient energy production and storage, with water splitting considered one of the most clean, environmentally friendly, and sustainable approaches to generate hydrogen. However, to meet industrial demands with electrolysis‐generated hydrogen, the development of a low‐cost and efficient catalyst for the oxygen evolution reaction (OER) is critical, while conventional catalysts are mostly based on precious metals. Many studies have thus focused on exploring new efficient nonprecious‐metal catalytic systems and improving the understandings on the OER mechanism, resulting in the design of catalysts with superior activity compared with that of conventional catalysts. In particular, the use of multimetal rather than single‐metal catalysts is demonstrated to yield remarkable performance improvement, as the metal composition in these catalysts can be tailored to modify the intrinsic properties affecting the OER. Herein, recent progress and accomplishments of multimetal catalytic systems, including several important groups of catalysts: layered hydroxide, spinel, and amorphous metal oxides along with the theoretical principles of activity enhancement in multimetal systems are reviewed. Finally, this is concluded by discussing remaining challenges to achieve further improvements of OER catalyst activities.