Novel engineering of ruthenium‐based electrocatalysts for acidic water oxidation: A mini review

Abstract

The oxygen evolution reaction (OER) is pivotally involved in proton exchange membrane water electrolyzers (PEMWEs). However, the commercialized iridium‐based catalysts often suffer from severe sluggish kinetics, eventually deteriorating the polarization and overall PEMWEs performance. Therefore, to develop OER electrocatalysts with promising reaction kinetics and high stability is of great significance for PEMWEs. Compared to iridium, the ruthenium‐based catalysts possess lower price and higher activity in acidic water oxidation, which promises Ru‐based materials to replace the state‐of‐the‐art IrOx. Yet, the less stable ruthenium than iridium impedes its real applications. In this mini review, recent knowledge of feasible engineering strategies for migrating the Ru‐based electrocatalysts' stability is summarized. In order to improve performance and durability, basic fundamentals of acidic OER on nanoscale and molecular engineered Ru‐based electrocatalysts are briefly introduced. In the end, the challenges and outlook for engineering novel Ru‐based electrocatalysts are presented.

Revealing the pH-Universal Electrocatalytic Activity of Co-Doped RuO2 toward the Water Oxidation Reaction

“…The peak at the binding energy of 288.14 eV belongs to the surface-functionalized organic CO bonds. Figure S22b gives the high-resolution XPS spectra of O 1s, where the peaks at binding energies of 529.22, 530.81, 532.3, and 535.1 eV are ascribed to the Ru–O, hydroxyl groups, adsorbed water molecules, and organic C–O bonds, respectively. , The Co 2p orbital does not show any characteristic binding energy peak (Figure S22c), which might be due to the low content of the cobalt ions after OER. From the post-OER analysis, it is observed that the robustness of the catalyst Co-RuO 2 was retained, as proved by means of FE-SEM, HR-TEM, HAADF color mapping, EDS, and XPS analyses.…”

Iridium-based catalysts for oxygen evolution reaction in acidic media: Mechanism, catalytic promotion effects and recent progress

“…Different crystal planes of the catalyst also exhibit different coordination atoms and surface energies, and the selective exposure of active surfaces on the crystals can significantly improve their electrocatalytic activity [75,76]. For example, two Ir nanocrystals (one with a flat surface enclosed by (100) facets and the other with a concave surface containing numerous high-index planes) were prepared by depositing an Ir capping layer on Pd nanocubes [1]. During the OER process, the concave Ir crystals with high-index planes promoted the formation of the surfactant IrO x , leading to a gradual increase in activity, while the planar Ir crystals surrounded by (100) facets exhibited a gradual decrease in activity.…”

“…The growing challenges from the energy crisis and environmental pollution necessitate the development of appropriate renewable energy storage and conversion technologies [1,2]. Renewable energy sources such as wind and solar energy are expected to be an effective way to power the clean and sustainable energy infrastructure [3,4].…”

Advances and status of anode catalysts for proton exchange membrane water electrolysis technology

“…It has been reported that with the introduction of foreign elements, such as V, Sn, Co, Ni, Zn, Fe, W, and La, the electronic structure of the Ru site can be modulated and prevent the formation of oxygen vacancies, and thus is effective to improve the stability of Ru-based anode catalysts. 102,103 Recently, Hao et al synthesized the W 0.2 Er 0.1 -Ru 0.7 O 2Àd anode catalyst by bimetallic doping, enabling this catalyst to exhibit long-term stability for 500 h. 104 They found that the W and Er dopants were capable of downshifting the O 2p-band center to the Fermi level, which increased the oxygen vacancy formation energy. The authors believed that the increase of the oxygen vacancy formation energy inhibits the direct O-O coupling together from the lattice of W 0.2 Er 0.1 Ru 0.7 O 2Àd , which makes the OER inclined to the AEM and reduces the tendency of Ru dissolution and oxidation (Fig.…”