A well-designed fencelike Co3O4@MoO3 derived from Co foam for enhanced electrocatalytic HER

A fencelike Co3O4@MoO3 was fabricated successfully via solvent etching strategy for enhanced electrocatalytic hydrogen evolution reaction (HER). Benefiting from the excellent synergistic effect between Co3O4 and MoO3, fencelike Co3O4@MoO3 exhibited enhanced HER performance of low overpotential (158 mV at 10 mA cm−2) and small Tafel slope (148 mV dec−1), thereby indicating the higher intrinsic catalytic kinetics in fencelike Co3O4@MoO3. From DFT results, the high electrocatalytic HER performance was attributed to the excellent electronic regulation of Co3O4. Simultaneously, MoO3 could serve as electron transport medium and thus migrate the electron transfer trend of Co3O4 → MoO3 → H2O. Therefore, an electron-rich region around H2O was formed due to electrons accumulation, facilitating the decomposition of H2O. Furthermore, Co3O4@MoO3 showed a more negative EH2O* (−4.94 eV) than that of Co3O4 (6.09 eV) and MoO3 (1.72 eV). Besides, the d orbital center of Co atom displayed a positive shift from −1.27 to −1.22 eV, demonstrating that Co could directly facilitate the activization and decomposition of H2O. What’s more, after introducing Co3O4 in MoO3, the H-O bond of H2O was extended from 0.989 to 0.990 Å, which directly confirmed that the synergistic effect between Co3O4 and MoO3 could facilitate H-O bond breaking.