Efficient hydrogen production at a rationally designed MoSe2@Co3O4 p-n heterojunction.

The MoSe 2 @Co 3 O 4 with excellent photocatalytic properties was prepared by simple hydrothermal and physical mixing methods. Combined with other characterizations such as XRD, XPS, photoelectrochemical characterization experiments and UV–vis diffuse reflectance spectra, the possible hydrogen production mechanism was proposed. The Fermi level of Co 3 O 4 is closer to the valence band. In contrast, MoSe 2 ′s Fermi level is closer to the conduction band position. The electrons in the CB of Co 3 O 4 are transferred to the CB of MoSe 2 to participate in the reaction under the action of the built-in electric field. During the past several years, transition metal compounds have shown high activity in the field of photocatalysis. Therefore, the MoSe 2 @Co 3 O 4 with excellent photocatalytic properties through simple hydrothermal and physical mixing methods was prepared. This composite material was composed of n -type semiconductor MoSe 2 and p-type semiconductor Co 3 O 4. After optimizing the loading of Co 3 O 4 , the optimal hydrogen production can reached 7029.2 μmol g-1h−1, which was 2.34 times that of single MoSe 2. In addition, some characterization methods were used to explore the hydrogen production performance of the composite catalyst under EY sensitized conditions. Among them, the UV–vis diffuse reflectance spectra suggests that MoSe 2 @Co 3 O 4 exhibits stronger visible light absorption performance than the single material. Fluorescence performance and photoelectrochemical characterization experiments further prove that, the special structure formed by MoSe 2 and Co 3 O 4 and the existence of p-n heterojunction effectively accelerate the separation and transfer of carriers meanwhile inhibit the recombination probability of electron-hole pairs. Combined with other characterizations such as XRD, XPS, SEM and BET, the possible hydrogen production mechanism was proposed. [ABSTRACT FROM AUTHOR]