Effectiveness of strain and dopants on breaking the activity-stability trade-off of RuO2 acidic oxygen evolution electrocatalysts
Yang Liu, Yixuan Wang, Hao Li, Min Gyu Kim, Ziyang Duan, Kainat Talat, Jin Yong Lee, Mingbo Wu, Hyoyoung Lee
Abstract
Ruthenium dioxide electrocatalysts for acidic oxygen evolution reaction suffer from mediocre activity and rather instability induced by high ruthenium-oxygen covalency. Here, the tensile strained strontium and tantalum codoped ruthenium dioxide nanocatalysts are synthesized via a molten salt-assisted quenching strategy. The tensile strained spacially elongates the ruthenium-oxygen bond and reduces covalency, thereby inhibiting the lattice oxygen participation and structural decomposition. The synergistic electronic modulations among strontium-tantalum-ruthenium groups both optimize deprotonation on oxygen sites and intermediates absorption on ruthenium sites, lowering the reaction energy barrier. Those result in a well-balanced activity-stability profile, confirmed by comprehensive experimental and theoretical analyses. Our strained electrode demonstrates an overpotential of 166 mV at 10 mA cm−2 in 0.5 M H2SO4 and an order of magnitude higher S-number, indicating comparable stability compared to bare catalyst. It exhibits negligible degradation rates within the long-term operation of single cell and PEM electrolyzer. This study elucidates the effectiveness of tensile strain and strategic doping in enhancing the activity and stability of ruthenium-based catalysts for acidic oxygen evolution reactions. Ruthenium dioxide electrocatalysts for acidic oxygen evolution suffer from mediocre activity and poor stability due to high ruthenium-oxygen covalency. Here, the authors report the effectiveness of tensile strain and electronic dopants in improving both activity and stability.