Constructing a Novel Surfactant-free MoS2 Nanosheet Modified MgIn2S4 Marigold Microflower: An Efficient Visible-Light Driven 2D-2D p-n Heterojunction Photocatalyst toward HER and pH Regulated NRR

摘要

Nowadays the major research objective is to find an efficient renewable energy source which can be a potential solution to all our ongoing problems. With this regard, the interest has been blossoming toward effective photocatalytic HER and NRR at ambient condition. For the optimization of photocatalytic H-2 evolution and NH3 production it is an exigent task to design a suitable photocatalytic semiconductor that hinders the low electron-hole separation efficiency. Benefiting from the combination of a 2D-2D semiconductor, we have proposed for the first time a series of p-MoS2/n-MgIn2S4 marigold flower-like heterojunction composites, with an excellent morphological contact interface through a facile two step hydrothermal process. The smart 2D-2D heterojunction structure provides large contact surface sites which reduce the migration distance between the separation sites of the photogenerated charge carrier to the heterojunction interface. This electron-rich system provided the multielectron pathway for the efficient reduction of nitrogen and can avoid the formation of high-energy intermediates. Thus, the high photocatalytic performance can be attributed to the heterojunction formation between two nanosheet, abundant exposed active sites via S-S linkage on the edge of metal sulfides and effective excitons separation. The developed MoS2/MIS heterojunction photocatalysts attain a high rate of NH3 production which is nearly 4 and 7 times higher than the bare MoS2 and MIS, and the rate of H-2 evolution is 4 times higher than the bare MIS. The current investigation provides an excellent strategy to promote photocatalytic HER and NRR and sheds some light toward the development of efficient 2D based bifunctional materials.