Hierarchical palladium catalyst for highly active and stable water oxidation in acidic media

Jing Peng; Haofeng Sun; Kun Ni; Jiajing Wu; Xinyu Sun; Yueqi Su; Han Cheng; Yuhua Liu; Yuqiao Guo; Wentuan Bi; Yanwu Zhu; Changzheng Wu; Yi Xie

doi:10.1093/nsr/nwac108

Hierarchical palladium catalyst for highly active and stable water oxidation in acidic media

Natl Sci Rev. 2022 Jun 9;10(2):nwac108. doi: 10.1093/nsr/nwac108. eCollection 2023 Feb.

Authors

Jing Peng¹, Haofeng Sun¹, Kun Ni¹, Jiajing Wu¹, Xinyu Sun¹, Yueqi Su¹, Han Cheng¹, Yuhua Liu¹, Yuqiao Guo¹, Wentuan Bi^{1

2}, Yanwu Zhu¹, Changzheng Wu^{1

2}, Yi Xie^{1

2}

Affiliations

¹ Hefei National Laboratory for Physical Science at the Microscale, CAS Center for Excellence in Nanoscience, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, China.
² Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230026, China.

Abstract

Acidic water electrolysis is of great importance for boosting the development of renewable energy. However, it severely suffers from the trade-off between high activity and long lifespan for oxygen evolution catalysts on the anode side. This is because the sluggish kinetics of oxygen evolution reaction necessitates the application of a high overpotential to achieve considerable current, which inevitably drives the catalysts far away from their thermodynamic equilibrium states. Here we demonstrate a new oxygen evolution model catalyst-hierarchical palladium (Pd) whose performance even surpasses the benchmark Ir- and Ru-based materials. The Pd catalyst displays an ultralow overpotential (196 mV), excellent durability and mitigated degradation (66 μV h^-1) at 10 mA cm^-2 in 1 M HClO₄. Tensile strain on Pd (111) facets weakens the binding of oxygen species on electrochemical etching-derived hierarchical Pd and thereby leads to two orders of magnitudes of enhancement of mass activity in comparison to the parent Pd bulk materials. Furthermore, the Pd catalyst displays the bifunctional catalytic properties for both oxygen and hydrogen evolutions and can deliver a current density of 2 A cm^-2 at a low cell voltage of 1.771 V when fabricated into polymer electrolyte membrane electrolyser.

Keywords: acidic condition; electrolysis; oxygen evolution reaction; palladium; strain.