Fast synthesis of low Ru doped CoOx/CeO2 nanosheet arrays with abundant heterointerfaces for highly efficient overall water splitting

• Published in: International journal of hydrogen energy 2024-10, Vol.88, p.199-208
• Main Authors: Deng, Yue, Tan, Linli, Wang, Tingting, Bai, Shi, Sun, Jinfeng, Guo, Junxia, Li, Tiantian, Liu, Gang, Zhang, Shaofei
• Format: Article
• Language: English
• Subjects: Bifunctional electrocatalysts; Heterointerface; Low Ru doping; Nanosheet arrays; Water splitting
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.09.217

The development of a simple and large-scale strategy for enhancing the intrinsic activity and reaction kinetics of nano-electrocatalyst for water splitting is crucial but challenging. Herein, a Ru-doped CoOx/CeO2 heterojunction catalyst with nanosheet arrays grown on an iron foam (named R-Ru@CoOx/CeO2/IF) was synthesized via fast solution combustion and low-temperature reduction processes. Low Ru doping (3.56 wt%) creates the lattice strain on the catalyst and modified the electronic structure, which is essential for optimizing the adsorption of reaction intermediates. Furthermore, benefiting from the desired nanosheet array framework, heterojunction structure, and abundant oxygen vacancies, the self-supporting electrode possesses sufficient active sites and fast mass/charge transport kinetics for promoting hydrogen and oxygen evolution reactions (HER and OER, respectively). Consequently, the R-Ru@CoOx/CeO2/IF exhibits ultralow overpotentials of 44 and 212 mV at 10 mA cm−2 for the HER and OER, respectively, in an alkaline solution; it also exhibits excellent stability with an overall activity superior to those of most reported oxide catalysts. Particularly, the assembled R-Ru@CoOx/CeO2/IF || R-Ru@CoOx/CeO2/IF symmetric electrolyzer only requires 1.44 and 1.61 V to reach 10 and 100 mA cm−2, respectively, and the decline in its activity is satisfactory after 100 h of durability testing at 1000 mA cm−2. The proposed simple and large-scale strategy has potential in the development of low noble-metal doped electrocatalysts for producing high-density and green hydrogen. [Display omitted] •A low Ru doped CoOx/CeO2 nanosheet array electrode was prepared.•Rapid solution combustion induces Ru doping into lattice of Co3O4.•Ru dopants synergy with heterointerfaces to optimize the electronic structure and adsorption of reaction intermediates.•Surface reconstruction from oxide to oxyhydroxide was revealed.•R-Ru@Co/Ce/IF showed high-efficient HER, OER, and overall water splitting properties.