Stabilizing non-iridium active sites by non-stoichiometric oxide for acidic water oxidation at high current density

Lingxi Zhou; Yangfan Shao; Fang Yin; Jia Li; Feiyu Kang; Ruitao Lv

doi:10.1038/s41467-023-43466-x

Stabilizing non-iridium active sites by non-stoichiometric oxide for acidic water oxidation at high current density

Nat Commun. 2023 Nov 23;14(1):7644. doi: 10.1038/s41467-023-43466-x.

Authors

Lingxi Zhou^#¹, Yangfan Shao^#², Fang Yin², Jia Li³, Feiyu Kang^{2

4}, Ruitao Lv^{5

6}

Affiliations

¹ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
² Institute of Materials Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
³ Institute of Materials Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China. li.jia@sz.tsinghua.edu.cn.
⁴ Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
⁵ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. lvruitao@tsinghua.edu.cn.
⁶ Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. lvruitao@tsinghua.edu.cn.

^# Contributed equally.

Abstract

Stabilizing active sites of non-iridium-based oxygen evolution reaction (OER) electrocatalysts is crucial, but remains a big challenge for hydrogen production by acidic water splitting. Here, we report that non-stoichiometric Ti oxides (TiO_x) can safeguard the Ru sites through structural-confinement and charge-redistribution, thereby extending the catalyst lifetime in acid by 10 orders of magnitude longer compared to that of the stoichiometric one (Ru/TiO₂). By exploiting the redox interaction-engaged strategy, the in situ growth of TiO_x on Ti foam and the loading of Ru nanoparticles are realized in one step. The as-synthesized binder-free Ru/TiO_x catalyst exhibits low OER overpotentials of 174 and 265 mV at 10 and 500 mA cm^-2, respectively. Experimental characterizations and theoretical calculations confirm that TiO_x stabilizes the Ru active center, enabling operation at 10 mA cm^-2 for over 37 days. This work opens an avenue of using non-stoichiometric compounds as stable and active materials for energy technologies.