TY - JOUR
T1 - Reversible lattice oxygen participation in Ru1-xO2-x for superior acidic oxygen evolution reaction
AU - Cao, Jia
AU - Liang, Xiongyi
AU - Gao, Wei
AU - Yin, Di
AU - Bu, Xiuming
AU - Yang, Siwei
AU - Xiao, Chuqian
AU - Wang, Shaoyan
AU - Zeng, Xiao Cheng
AU - Ho, Johnny C.
AU - Wang, Xianying
PY - 2025/6/14
Y1 - 2025/6/14
N2 - A stable and efficient RuO2-based electrocatalyst for the acidic oxygen evolution reaction (OER) is essential to replace the current IrO2 anode in proton-exchange membrane water electrolysis (PEMWE). Herein, we introduce RuO2 catalysts designed with coexisting oxygen and ruthenium vacancies using a metal–organic pyrolysis method. In 0.5 M H2SO4 using a three-electrode configuration, the catalyst delivers a low overpotential of 193 mV at 10 mA cm−2. Experimental and theoretical analyses reveal facet-dependent mechanisms: oxygen vacancies stabilize (110) and (101) facets by suppressing excessive Ru vacancy formation during reconstruction, while Ru vacancies on (101) uniquely activate lattice oxygen to enable a reversible lattice oxygen-mediated (LOM) cycle. DFT calculations rationalize this behavior: Ru vacancies lower the deprotonation of adsorbed hydroxyl (RDS) to 1.51 eV on (101) facets, while lattice oxygen coupling via the LOM proceeds at a remarkably low barrier of 1.02 eV, synergistically promoting rapid oxygen replenishment and durable cycling. In contrast, the (110) facet suffers from prohibitive barriers (>2.0 eV) in both adsorbate-driven and lattice oxygen pathways. Consequently, the (101)-dominant catalyst operates stably at 100 mA cm−2 in PEMWE for 200 h, outperforming the conventional IrO2 benchmark.© The Royal Society of Chemistry 2025
AB - A stable and efficient RuO2-based electrocatalyst for the acidic oxygen evolution reaction (OER) is essential to replace the current IrO2 anode in proton-exchange membrane water electrolysis (PEMWE). Herein, we introduce RuO2 catalysts designed with coexisting oxygen and ruthenium vacancies using a metal–organic pyrolysis method. In 0.5 M H2SO4 using a three-electrode configuration, the catalyst delivers a low overpotential of 193 mV at 10 mA cm−2. Experimental and theoretical analyses reveal facet-dependent mechanisms: oxygen vacancies stabilize (110) and (101) facets by suppressing excessive Ru vacancy formation during reconstruction, while Ru vacancies on (101) uniquely activate lattice oxygen to enable a reversible lattice oxygen-mediated (LOM) cycle. DFT calculations rationalize this behavior: Ru vacancies lower the deprotonation of adsorbed hydroxyl (RDS) to 1.51 eV on (101) facets, while lattice oxygen coupling via the LOM proceeds at a remarkably low barrier of 1.02 eV, synergistically promoting rapid oxygen replenishment and durable cycling. In contrast, the (110) facet suffers from prohibitive barriers (>2.0 eV) in both adsorbate-driven and lattice oxygen pathways. Consequently, the (101)-dominant catalyst operates stably at 100 mA cm−2 in PEMWE for 200 h, outperforming the conventional IrO2 benchmark.© The Royal Society of Chemistry 2025
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U2 - 10.1039/D5TA01484K
DO - 10.1039/D5TA01484K
M3 - RGC 21 - Publication in refereed journal
SN - 2050-7488
VL - 13
SP - 16807
EP - 16815
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 22
ER -