Synthesis and characterization of 2D layered MoS2 for catalytic and electrochemical applications

Abstract

MoS2 has been identified as a possible option for energy storage and catalysis due to its cost-effectiveness and low toxicity and has been demonstrated to possess relatively high performance. To further explore its potential applications, such as energy storage, electrocatalysis, and visible-light-driven photocatalysis, defect-rich MoS2 nanostructures were produced on a large scale using simple, cost-effective chemical routes. This thesis details a unique synthesis method and materials design route to broaden the application of atomically thin MoS2 nanostructures. The introduction of vacancies and active site engineering have been recognized as conceivable approaches to increase the number of active sites and speed up the electron transfer rate of 2H-MoS2. Additionally, a two-step defect engineering process has been designed to prepare vacancies-rich MoS2, using hydrothermal treatment and ultra-sonication. The performance of the electrochemical hydrogen evolution reaction, photocatalytic activity in various organic dyes, and supercapacitor performance have all been thoroughly studied. It has been shown that the catalytic activities are enhanced by the increase of defect concentrations in MoS2, indicating that defect engineering is an effective way to improve the catalytic performance of MoS2 nanostructures. In-situ hydrothermal synthesis and liquid-phase exfoliation were used to create MoS2/MnO2 nanostructured composite. The composite was used as the electrode for a solid-state supercapacitor, displaying superb electrochemical characteristics, such as a high energy and power density, and lasting 5000 charging-discharging cycles with 84.1% of its original capacity retained. newline