Recent advances in heteroatom-doped RuO₂ electrocatalysts for efficient acidic oxygen evolution reaction

Highly active and durable acidic oxygen evolution reaction (OER) electrocatalyst is a vital component of cost-effective proton exchange membrane water electrolyzer. Rutile-phase RuO₂ has inspired extensive attention as an acidic OER electrocatalyst due to its lower cost and similar activity compared to IrO₂. However, RuO₂ often suffers from severe dissolution and even structural collapse at high potentials due to the irreversible overoxidation of Ru into soluble RuO₄ species, resulting in a dramatic degradation of performance. Thus, suppressing Ru dissolution and improving intrinsic activity are crucial challenges in the design of RuO₂-based electrocatalysts. Extensive efforts have proven that incorporating foreign metal/non-metal dopants into RuO₂ is an extremely practical and effective strategy for boosting RuO₂. In this review, an overview of mechanisms of acidic OER and classification of the doping forms is first provided. Subsequently, a comprehensive review of RuO₂-based electrocatalysts with various doping types is presented, along with the underlying mechanisms that facilitate breaking the trade-off between activity and stability. Finally, our insights into current challenges and future research trends are proposed for developing robust RuO₂-based electrocatalysts toward acidic OER.