Hydrogen Photosynthesis through Schottky Junction of RGO-NiPO and the Perspective of the Mechanism

Abstract

The synthesis of an economical and efficient photocatalyst for the fabrication of clean H-2 from water splitting is significant for the actual application. In this work, we have reported the low-cost synthesis of reduced graphene oxide embedded nickel phosphate (RGO-NiPO) photocatalyst by low-temperature hydrothermal reaction system. The composite showed great potential in the photoreduction reaction of water under visible spectrum irradiation. The morphological analysis of RGO-NiPO explains an amazing interaction between the RGO and NiPO surface which efficiently interferes with the charge carrier losses during the water reduction reaction in the presence of light. Furthermore, this phenomena was evidenced from the time-resolved photoluminescence spectra, where the decay components were calculated to have a shorter decay time (1.40 ns) in the case of 12RGO-NiPO than that of NiPO (5.3 ns), implying efficient e(-) transfer across the NiPO-RGO interface. The NiPO nanostrings were face-to-face assembled on the surface of the graphene sheet, which makes the intimate contact between the nanostrings and graphene feasible. Such noble-metal-free photocatalyst may provide an approach for the design of very efficient water-splitting catalysts, which are predicted to be applied to the actual photocatalytic water-splitting industry. Owing to the synergetic effect of the distinguishable structural and compositional privileges, the RGO-NiPO nanostrings showed admirable activity with a H-2 rate of 9000 mu mol/h/g and high photocatalytic water-splitting stability without the use of any other cocatalysts.