Self-optimizing interface engineering with simultaneous activation of surface lattice oxygen for enhanced electrocatalytic water oxidation

• Published in: International journal of hydrogen energy 2024-12, Vol.94, p.80-86
• Main Authors: Liu, Taohua, Xiao, Rui, Wang, Mengen, Li, Yingwei, Wang, Kang, Ma, Baojun, Wang, Wei
• Format: Article
• Language: English
• Subjects: Electrochemical water splitting; FeV-LDHs; Oxygen evolution reaction; Self-optimizing interface; Surface lattice oxygen
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.11.095

Iron vanadium (FeV)-based bimetallic oxides/hydroxides are promising electrocatalysts for water splitting. However, during the continuous OER process, most FeV catalysts are subjected to violent lattice distortion, resulting in a large amount of VOx dissolved into the electrolyte. Here, we propose an innovative material design strategy that not only replenishes the leaching V site of FeV-LDHs but also promotes the formation of VOOH on the surface, thereby establishing a self-optimizing interfacial interaction between VOOH and FeV-LDHs. The vacancies generated by interfacial rearrangement promote the adsorption of oxygen intermediates, while also contributing to a regulated electronic structure of Fe and V. Moreover, the presence of shared V–O bonds between VOOH and FeV-LDHs serves as an efficient charge transfer pathway, which not only stabilizes the high valence states of V but also enhances the activity of surface lattice oxygen in the OER process. Furthermore, the continuous adsorption of OH− promotes the formation of more oxygen vacancies in the catalyst system, thereby facilitating the deprotonation process and the production of O2. As a result, the VOOH/FeV-LDHs demonstrate exceptional OER performance, requiring a mere 158 and 217 mV overpotential to achieve current densities of 10 and 200 mA cm−2, respectively. The novel hybrid structures of VOOH/FeV-LDHs were fabricated with the aim of achieving in-situ reconstruction of the amorphous VOOH layer on the surface, while preserving the bulk structure of FeV-LDHs. The presence of shared V–O bonds at the interface promotes efficient charge transfer, stabilizing high valence states of V and enhancing surface lattice oxygen activity during OER conditions. [Display omitted] •The VOOH/FeV-LDHs establish a self-optimizing interfacial interaction.•The occupation of V site in FeV-LDHs by VOOH leads to structural rearrangement.•The VOOH render FeV-LDHs bulk sites potentially suitable for adsorbing OER intermediates.•The V–O bond promotes charge transfer and stabilizes the high valence state of V.•The facilitated interfacial electron transfer produces more active O2−x species.