Study of Optical, Photocatalytic and Electrochemical applications of MoS₂ and its Nanocomposites

Chatti, Manjunath (2015) Study of Optical, Photocatalytic and Electrochemical applications of MoS₂ and its Nanocomposites. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Manjunath Chatti (10MS09)) MS_Thesis_Manjunath_Chatti.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

The fundamental research on 2D materials has drawn much attention in recent years. The application of 2D materials in electrochemical and pollutants degradation provides a very promising method in solving energy crisis and environment pollution. Among various materials, molybdenum disulfide (MoS₂) has been widely studied and applied in practice due to its physical stability, low cost, high photocatalytic efficiency and good nonlinear optical (NLO) properties. However, the workable window of MoS₂ is confined to visible region of the solar spectrum. This thesis details about the strategy to extend the absorption window of layered transition metal dichalcogenides taking MoS2 as an example for near infrared (NIR) photocatalytic and optical limiting applications. This is achieved indirectly by integrating MoS₂ and NaYF₄-Yb/Er nanomaterials. The latter has the ability to convert NIR radiation in to visible radiation via the process, upconversion (UC). This is expected to enhance the photocatalytic activity through efficient utilization of NIR photons. Infact, we observed the faster degradation of rhodamine B dye for MoS₂-NaYF₄:Yb/Er nanocomposite. In another study we have synthesized MoS₂ nanosheets through an environmentally friendly microwave assisted technique, which is cost effective and less time consuming. The as synthesized MoS₂ nanosheets are found to show excellent double layer capacitive properties due to its large surface area and larger interlayer separation. The charge storage mechanism is diffusion dependent. The diffusion of ions occurs within the atomic layers of MoS2. This increases the available surface area for charge storage. This sample shows enhanced specific capacitance value (~350 F/g) which is much larger than recently reported value of some MoS2 based supercapacitor. Electrochemical impedance spectroscopy (EIS) suggests that excellent charge transport property at the electrode-electrolyte interface. The above results clearly suggest that the developed nanomaterials could show promising applications in supercapacitor, NIR photocatalysis, optical limiting, etc.

Actions (login required)

View Item