Suppression of Oxygen Vacancies in Rutile Ruo₂ via In Situ Exsolution for Enhanced Water Electrocatalysis

Abstract

Elemental vacancies are proposed as an effective approach to tuning the electronic structure of catalysts that are critical for energy conversion. However, for reactions such as the sluggish oxygen evolution reaction, the excess of oxygen vacancies (VO) is inevitable and detrimental to catalysts’ electrochemical stability and activities, e.g., in the most active RuO2. While significant work is carried out to hinder the formation of VO, the development of a fast and efficient strategy is limited. Herein, a protection SrO layer produced successfully at the surface of RuO2 with the in situ exsolution method with perovskite SrRuO3 as the precatalyst, which could significantly hinder the generation of VO. Benefited from the suppression of VO, the surface‐modified RuO2 requires a low overpotential of 290 mV at 100 mA cm−2, accompanied by remarkably high electrochemical stability (100 h) and Faraday efficiency (≈100%). Theoretical investigation reveals that the formation energy of VO in RuO2 is almost doubled in the exsolved RuO2 phase as a result of the weakened RuO bond covalency. This work not only provides insight into the structural evolution of perovskite oxide catalysts but also demonstrates the feasibility of controlling vacancy formation via in situ exsolution.

Observation of a robust catalyst support based on metallic glass for large current-density water electrolysis

“…The peaks at binding energies of 529.8, 531.4 and 533 eV can be assigned to metal–O bonds, surface-absorbed hydroxyl group, and adsorbed water molecular, respectively. 57 The high percentage of surface-absorbed hydroxyl group coverage may improve the formation of the O–O bond in –OOH group, which is beneficial for the OER processes. 57,58…”

“…57 The high percentage of surface-absorbed hydroxyl group coverage may improve the formation of the O–O bond in –OOH group, which is beneficial for the OER processes. 57,58…”

Competitive Adsorption Mechanism of Defect‐Induced d‐Orbital Single Electrons in SrRuO3 for Alkaline Hydrogen Evolution Reaction

“…The in situ surface reconstruction of SRO, resulting from the exsolution of elements during electrochemical reactions, leads to the formation of new active centers, thereby enhancing the activity and stability of the catalyst. [19,20] More importantly, SRO exhibits spin-controllable ferromagnetic properties, further adding to its appeal for electrocatalytic applications. [21] Several studies have reported spin-related phenomena in SRO, demonstrating the influence of crystal orientation and defects on the presence of high-spin states.…”