One-Pot Synthesis of Chlorophyll-Assisted Exfoliated MoS2/WS2 Heterostructures via Liquid-Phase Exfoliation Method for Photocatalytic Hydrogen Production

Abstract

Developing strategies for producing hydrogen economically and in greener ways is still an unaccomplished goal. Photoelectrochemical (PEC) water splitting using photoelectrodes under neutral electrolyte conditions provides possibly one of the greenest routes to produce hydrogen. Here, we demonstrate that chlorophyll extracts can be used as an efficient exfoliant to exfoliate bulk MoS2 and WS2 to form a thin layer of a MoS2/WS2 heterostructure. Thin films of solution-processed MoS2 and WS2 nanosheets display photocurrent densities of −1 and −5 mA/cm2, respectively, and hydrogen evolution under simulated solar irradiation. The exfoliated WS2 is significantly more efficient than the exfoliated MoS2; however, the MoS2/WS2 heterostructure results in a 2500% increase in photocurrent densities compared to the individual constituents and over 12 h of PEC durability under a neutral electrolyte. Surprisingly, in real seawater, the MoS2/WS2 heterostructure exhibits stable hydrogen production after solar illumination for 12 h. The synthesis method showed, for the first time, how the MoS2/WS2 heterostructure can be used to produce hydrogen effectively. Our findings highlight the prospects for this heterostructure, which could be coupled with various processes towards improving PEC efficiency and applications.

Covalently Interconnected Polymer Dot–WS2 Nanosheet Heterostructure for Visible Light-Driven Hydrogen Production

“…These changes in the XRD pattern of exfoliated WS 2 nanosheets indicate the successful formation of WS 2 nanosheets after the sonication treatment of bulk WS 2 in the presence of chlorophyll. 42 These results are in agreement with the TEM results of exfoliated WS 2 nanosheets (Figure S3). Moreover, we have measured the Raman spectrum of the exfoliated WS 2 nanosheets (the Raman spectrum is given in the inset of Figure 4d) with the two characteristic peaks at 351 and 419 cm −1 , corresponding to the vibration modes of 1 E 2g and A 1g , respectively.…”

“…These results well match with the literature reports and the JCPDS card (84-1398) of bulk WS 2 . , However, in the XRD spectrum of exfoliated WS 2 nanosheets, a lot of decrease in the intensity as well as enhancement in the full width at half-maxima broadening were observed. These changes in the XRD pattern of exfoliated WS 2 nanosheets indicate the successful formation of WS 2 nanosheets after the sonication treatment of bulk WS 2 in the presence of chlorophyll . These results are in agreement with the TEM results of exfoliated WS 2 nanosheets (Figure S3).…”

Recent Advances in Molybdenum Disulfide and Its Nanocomposites for Energy Applications: Challenges and Development

“…This novel method of synthesis has opened the door to exciting possibilities in the field of renewable energy. The MoS 2 /WS 2 heterostructure produced through this method has proven to be an effective catalyst for the production of hydrogen, which is a vital ingredient in a range of clean energy applications [ 100 ]. The study examined the electrocatalytic performance of 2H-MoS 2 nanosheets produced through LPE in N-dimethyl formamide, 1-methyl-2-pyrrolidinone, and formamide by examining their surface and interface functionalization.…”

Fabrication of WS2/WSe2 Z-Scheme Nano-Heterostructure for Efficient Photocatalytic Hydrogen Production and Removal of Congo Red under Visible Light

“…Transition metal tungsten sulfides have been broadly researched as excellent semiconductor photocatalysts [10,11]. Because of their outstanding photoelectric capability and particular band gap properties, they possess better potential in the field of photocatalytic activity.…”