In Situ Exsolution of Ba<sub>3</sub>(VO<sub>4</sub>)<sub>2</sub> Nanoparticles on a V-Doped BaCoO<sub>3−δ</sub> Perovskite Oxide with Enhanced Activity for Electrocatalytic Hydrogen Evolution
Dehuo Zhou, Fuhe Le, Wei Jia, Xianhao Chen
Abstract
The successful preparation of a perovskite-based heterostructure is important for broadening the applications of perovskites in the field of electrocatalysis, especially in a hydrogen evolution reaction (HER). Nevertheless, the limited active sites of perovskites severely hindered the HER properties. Herein, an in situ exsolution method was used to construct a nanocomposite based on V-doped BaCoO 3−δ decorated with Ba 3 (VO 4 ) 2 (BVCO19) for alkaline HER. The exsolved Ba 3 (VO 4 ) 2 can induce more Co 4+ ions on BaCoO 3−δ, which serves as active sites for the release of H 2 . Meanwhile, by regulating the valency of V and Co species, the catalyst can reach a charge balance by generating more oxygen vacancies, which greatly facilitates the adsorption and dissociation of H 2 O molecules. The synergistic effect between the oxygen vacancies and high-valence Co 4+ leads to an enhanced HER performance of BVCO19. The as-obtained catalyst delivers a low overpotential of 194 mV at 10 mA cm –2 as well as impressive stability for 100 h in alkaline media, which outperforms pristine BaCoO 3−δ and most of the nonprecious-based perovskite oxides. This work provides new insights into the preparation of perovskite-based heterostructure for boosting HER.