Electrochemical thinning and controlled insertion of chemical defects in MoS2 monolayers supported on graphite electrodes

• Grant number: 25/06125-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: September 01, 2025
• End date: August 31, 2029
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Murilo Santhiago
• Grantee: Renan Gabriel de Assis
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Campinas , SP, Brazil
• Associated research grant: 23/17576-4 - Controlled generation of chemical defects on the basal plane of molybdenum disulfide (MoS2), AP.R

Abstract

The controlled generation of chemical defects in the basal plane of molybdenum disulfide (MoS2) has enormous potential for modulating its electrical, optical, and electrochemical properties for various applications. To this end, one of the initial aspects is to obtain MoS2 monolayers with a high aspect ratio. Among the current methodologies, electrochemical routes using TiN electrodes or thin gold films stand out in producing these monolayers with high yields, simple instrumentation, mild conditions, and a fast process. However, to minimize contamination by metallic residues on the MoS2 monolayers during the characterization process, it is interesting to use non-metallic electrodes and expand the possibilities of electrodes for preparing these materials. In this context, carbon electrodes stand out due to their lower cost compared to gold, high durability, and stability. Thus, the project proposes using highly oriented pyrolytic graphite (HOPG) electrodes to prepare MoS2 monolayers with a high aspect ratio and to control the insertion of edge-type defects in the basal plane using nanofabrication routes. We also propose to fabricate electrodes containing suspended HOPG layers for the first time to characterize the defects generated in MoS2 in detail with atomic resolution. Understanding the areas containing defects will be fundamental to correlating them with the electrocatalytic activity of the electrodes for the hydrogen release reaction.