A DFT investigation on surface and defect modulation of the Co3O4 catalyst for efficient oxygen evolution reaction

• Published in: Surface science 2024-10, Vol.748, p.122544, Article 122544
• Main Authors: Huo, Chenxu, Lang, Xiufeng, Song, Guoxiong, Wang, Yujie, Ren, Shihong, Liao, Weidan, Guo, Hao, Chen, Xueguang
• Format: Article
• Language: English
• Subjects: Cobalt oxide; Density functional theory; Oxygen evolution reaction; Surface defects
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2024.122544

•Explored thermodynamically feasible oxygen evolution reaction pathways for perfect and defective Co3O4(111) surfaces.•The adsorbate evolution mechanism (AEM) of perfect Co3O4(111) surface for oxygen evolution reaction is superior to lattice oxygen mechanism (LOM).•Co vacancy promotes the formation of *OH, changes the potential determination steps of LOM and AEM, and promotes the surface oxygen evolution reaction.•Vacancy promotes the decomposition of water molecules and activates the LOM on the VO-Co3O4(111) surface. The electrolysis of a water for hydrogen production is a promising way to produce clean energy, but the sluggish oxygen evolution reaction (OER) limits the overall efficiency of water electrolysis. In this work, we investigated the water oxidation pathways on the perfect and defect Co3O4(111) surfaces by using density functional theory (DFT) calculations. We found that for the perfect surface the free energy barrier of the potential determining step (PDS) in the adsorbate evolution mechanism (AEM) of water is lower than that in the lattice oxygen mechanism (LOM). For the defect surfaces, cobalt vacancies are more easily formed than oxygen vacancies. The Co vacancy promotes the formation of *OH, changes the PDS of the LOM and AEM, and reduces the free energy barrier of both PDS. The PDS of the LOM pathway on the VCo2Co3O4(111) surface is the coupling step of the O adatom and lattice oxygen, which promotes the LOM process. Different from the OER mechanism on the perfect surface and the defect surface with Co vacancy, the LOM is perferred to occur on the defect surface with O vacancy. This work may provide new insight into the relationship between the surface structure and OER activity surface of the Co3O4 catalyst and help to design the efficient OER catalysts by surface and vacancy engineering. [Display omitted]