Enhanced photocatalytic H2 production activity by loading Ni complex on flower-like MoS2 nanomaterials

Abstract

Background

Exploring efficient H₂-production photocatalysts is very important for converting solar energy to chemical energy. Some approaches were developed to prevent the recombination of photogenerated electron-hole pairs, ultimately enhancing the photocatalytic H₂ production activity.

Methods

3D flower-like MoS₂ nanomaterials were surface-modified by the Ni complex as the redox mediator to make the composite photocatalysts. This work investigated the effect of zeta potential on the Ni-complex loading, charge separation, and photocatalytic H₂ production activity of MoS₂.

Significant findings

The Ni-complex with central cation can be loaded on MoS₂ with negative zeta potential due to the columb attraction force. The photogenerated carriers can transfer from MoS₂ to the central Ni ion of the complex due to the ligands-stabilized multiple oxidation states of Ni, leading to suppressed charge recombination. The FE-TEM mapping and XPS confirm the loading of Ni complex. The photoluminescence, photocurrent response, and EIS tests confirm the improved photoinduced charge separation of the Ni complex-modified photocatalyst. The flower-like microstructure of MoS₂ provides a large specific surface area and high light absorption. The H₂ production activity of MoS₂-Ni complex photocatalyst (3320 μmol g^{−1 h−1}) is higher than that of the pristine MoS₂ photocatalyst (2576 μmol g^{−1 h−1}).