A hollow core–shell structure material NiCo2S4@Ni2P with uniform heterojunction for efficient photocatalytic H2 evolution reaction

Abstract

A photocatalytic material, NiCo₂S₄@Ni₂P, with a unique hollow core–shell structure based on hollow spherical NiCo₂S₄, which has a structure that is greatly advantageous for heterogeneous photocatalytic reactions, was successfully prepared. The unique hollow core–shell structure formed a homogeneous surface heterojunction, which caused the composite photocatalytic material to exhibit better photocatalytic HER activity and stability than the initial NiCo₂S₄ in the dye-sensitized system. The photocatalytic HER rate of the optimal photocatalytic material, NiCo₂S₄@Ni₂P 10%, reached 77.97 μmol h⁻¹via the optimization of the photocatalytic H₂ evolution performance. XRD and XPS were used to study the crystal structure and valence state of the photocatalytic material, respectively. Additionally, its morphology and structure were observed by SEM and TEM, respectively. The CB and VB potentials were derived by combining empirical formulas based on the UV-vis DRS data. Finally, the photocatalytic HER mechanism was investigated by photoelectrochemical and PL tests combined with the above data.