Synthesis,Characterizations And Photocatalytic Oxygen Evolution Performance Of Ag₃PO₄/Ag/MoS₂ Catalyst

MoS₂/Ag₃PO₄ heterojunction photocatalysts have attracted great attention in dye degradation and water oxidation,in which Z-scheme plays a critical role in the catalytic performance as a result of energy band structure alignment between MoS₂ and Ag₃PO₄.Creating metal sites at composite interfaces as recombination centers of photo-generated electrons from conduction band?CB?of Ag₃PO₄ and holes from valence band?VB?of MoS₂ is an effective strategy to enhance the charge separation efficiency and photocatalytic performance.However,recombination centers are necessary for the work of a efficient Z scheme system.There is no proof for the existence of such recombination centers in MoS₂/Ag₃PO₄ materials.Strong coupled MoS₂/Ag dots/Ag₃PO₄ ternary heterojunction photocatalysts were fabricated by one-pot precipitation method,in which highly dispersed Ag dots are located at the MoS₂/Ag₃PO₄ interfaces and MoS₂ is bonded with PO₄^3-in the form of Mo-O-P.The fabricated MoS₂/Ag dots/Ag₃PO₄ photocatalyst presents a 2.8-fold enhancement of photocatalytic activity of water oxidation compared to that of pristine Ag₃PO₄,which is achieved for the first time.The great enhancement of photocatalytic performance can be ascribed to the improved Z scheme mechanism with strongly coupled MoS₂/Ag dots/Ag₃PO₄ ternary interfaces,in which highly dispersed Ag dots serve as efficient recombination centers resulting in the improved separation of photo-generated holes and electrons of Ag₃PO₄ as well as photocatalytic activity of oxygen evolution.To further improve the oxygen evolution performance,modification were carried out on Ag₃PO₄ and MoS₂,respectively.The Ni²⁺lattice doping on MoS₂ exhibited a higher oxygen production rate,as well as the size control of Ag₃PO₄.Through the reverse microemulsion method,the particle size of Ag₃PO₄ can be reduced to 5 nm and the sample MoS₂/Ag/nano Ag₃PO₄ has reached the highest enhancement of photocatalytic performance among the series of MoS₂/Ag₃PO₄ materials.Other modification methods,including the face control of Ag₃PO₄ and the surface treatment on MoS₂ were also tried and listed.