Durable ruthenium oxide catalysts for water oxidation reaction

Water electrolysis is an important way for high-purity hydrogen production. However, the oxygen evolution reaction (OER), as a key reaction, has a high energy barrier, and the associated catalyst is prone to failure. Therefore, efficient and stable OER catalysts are urgently required. Compared with commercial iridium oxide (IrO₂), ruthenium oxide (RuO₂) has a lower price and higher catalytic activity for OER due to its location at the near-top of the volcano plot, but has lower structural stability. Thus, an in-depth understanding of the failure mechanism of RuO₂ is conducive to the reaction pathway design and structural modulation for obtaining higher stable RuO₂ catalysts. Here, we discuss recent advances in the enhancement of the stability of RuO₂ catalysts. First, we analyze in depth the three failure modes of RuO₂, including the oxidation of Ru, the lattice oxygen evolution, and the catalyst exfoliation during the OER process. Second, to improve the durability of RuO₂ catalysts, five modification strategies, comprising defective engineering, strain engineering, phase engineering, interface engineering and microenvironmental engineering, are summarized, and corresponding enhancement mechanisms are also discussed. Finally, the challenges and possible solutions for further breakthroughs of RuO₂ catalysts are proposed, and the future research trends and prospects of RuO₂ catalysts are also envisioned. Undoubtedly, this work will contribute to the understanding and design of highly stable OER catalysts and beyond.