3D layered nano-flower MoS_x anchored with CoP nanoparticles form double proton adsorption site for enhanced photocatalytic hydrogen evolution under visible light driven

摘要

Three-dimensional (3D) nanoflower can inhibit lamellar stacking to expose more edge active sites, showing larger surface areas and shorter electron transport paths. In this work, with the help of polyvinylpyrrolidone (PVP) morphology modifier, three-dimensional (3D) nanoflower MoSx was synthesized by hydrothermal method. The ZIF-9(Co)-derived CoP nanoparticles adhere to MoSx by means of a three-dimensional flower structure to form a MoSx/CoP photocatalyst. The 3D nano-flower of MoSx with layered structure can be observed in TEM images. This unique layered structure not only effectively inhibits the mutual stacking of MoSx nanosheets but also play a good role in dispersing CoP nano particles. In addition, the unsaturated Mo and S atoms exposed to the edge also promote the edge activity of sulfur, playing the role of active sites. Meanwhile, the CoP can also serve as active sites, which P as base sites can trap the positively charged protons. During the catalytic reaction, the Co atom and the P atom act as the double proton adsorption site in the CoP [P(delta(-))-Co(delta(+))], which could accelerate the water cracking. Besides, PL, EIS and Mott-Schottky show that MoS. and CoP play a synergistic role during the reaction, and the contact between them opens up a channel for accelerating the electron transfer to avoid electron aggregation. Thus, the MoSx/CoP is exhibited lower overpotential, larger apparent current density and higher conductivity. The MoSx/CoP-20 shows the highest photo catalytic activity of 8730 mu mol g(-1)h(-1) under visible light irradiation. In this work, MoSx/CoP has excellent photocatalytic activity, which provides a reference for future energy innovation. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.