Study On Electrochemical Hydrogen Production Properties Of The Composite Films Based On MoS₂ Using Layer By Layer Self-assembly

Molybdenum disulfide?Mo S₂?nanosheets have excellent electrocatalytic hydrogen production.However,the preparation of promising catalytic materials based on the nanostructure is difficult to use,recover,lead to pollution and other problems.In order to solve the above problems,this paper proposed the method of employing interfacial molecular engineering to develop the interfacial electrocatalysts for hydrogen evolution reaction?HER?using Layer by Layer?Lb L?self-assembly technique with Mo S₂nanosheets as the electrocatalytic active unit and flexible conductive component.Initially,a new method for large-scale preparation of limited Mo S₂nanosheets was developed.The key of this method is to control deposition of Mo S₂in interfacial organic matrix?PAA/PAH?₆,and the Mo S₂nanosheets can be obtained after ultrasonic treatment.The xy plane size and thickness of the prepared nanosheets ranged from 100-200 nm and 10-20 nm,showing the characteristic electronic structure of the Mo S₂nanostructures.Then,the interfacial Lb L method was used to study the preparation of efficient HER interface structure based on Mo S₂nanoparticles.The interfacial assembly structure of Zn&N co-doped Mo S₂?Zn-N-Mo S₂?nanoparticles and the reduced graphene oxide?r GO?modified by PAH?poly?allylamine hydrochloride???Zn-N-Mo S₂/PAH-r GO?was constructed by Lb L process.The study found that the choice of the interfacial components with negative Zn-N-Mo S₂is the key to obtain the good interfacial catalytic structure for HER.When PAH-r GO was employed as the positive partner in Lb L assembly,the interfacial catalytic structure showed superior electrocatalytic HER characteristics.The catalytic capacity of Zn-N-Mo S₂composite interfacial structure for HER increased up to a limit of 16 bilayers and decreased with further growth of the number of bilayers.This phenomenon can be attributed to the competing effect between an increase in the number of active sites and a decrease in the electron transfer efficiency?growth of resistance?.It shows that the activity of the catalyst can be significantly regulated by the number of bilayers.XPS and DFT simulation clearly verified that the superior catalytic efficacy of?PAH-r GO/Zn-N-Mo S₂?n could be attributed to the fact that r GO effectively activated the basal plane S as the active sites.The binding energy of the planar S atoms clearly shift to a lower range by 0.5 e V and the?G_H*for the S element changes to-0.43 e V.Moreover,after capping with a Nafion layer,the interfacial catalysts exhibit high stability in long-term catalytic reactions.On the basis of discussing the preparation and interfacial assembly method of Mo S₂nanosheets,different conducting polymers?PANI?Ppy and PEDOT:PSS?with?conjugated system as the interface assembly partners were selected to composite with Mo S₂nanosheets.The interface structures with good catalytic performance were all obtained by the conducting polymers used as assembly primitives and the electrocatalytic performance of the composite films could be finely regulated by the number of bilayers.The interface structure prepared by Ppy showed better performance for HER than PANI.The research indicated that the ratio of bridging S₂^2-(or apical S^2-)in?Ppy/Mo S₂?composite multilayers was further increased.The presence of these higher energy peaks is related to the well-remained active HER species.When chose carbon cloth?CC?as the substrate,compared the?conducting polymers/Mo S₂?composite films with optimized number of bilayers,?PEDOT:PSS/Mo S₂?₈-CC had the largest current density.This paper reports a facile method to prepare Mo S₂-based composite interface structure forfinely regulating the HER performance,which provides an idea for the realization of catalysis and multifunctional application of Mo S₂nanosheets.