Green Synthesis of Pure and Doped Fluorescent C Dots and their Metal Chalcogenide Nanocomposite Materials for Hydrogen Generation and Waste Water Treatment

Abstract

The research work titled Green synthesis of pure and doped fluorescent C-dots and their metal chalcogenide nanocomposite materials for hydrogen generation and waste water treatment intended to address the current alarming situations prevailing in the energy and environmental sectors such as energy depletion and water pollution. The work primarily focused on the synthesis of carbon nanodots (C-dots) from natural sources such as newlinevegetable/plant extracts and bio-waste. C-dots had been prepared from beetroot juice (b-CDs) and the peels of the vegetable, snake gourd (g-CDs). The morphological and chemical composition of C-dots have been confirmed using advanced characterization techniques such as XRD, FTIR, Raman spectroscopy and HRTEM while UV-Visible absorption spectroscopy and photoluminescence spectroscopy had been used to investigate their optical characteristics. The utilisation of natural sources/ kitchen garbage with addition of no chemicals for the carbon dots synthesis added an advantage of go green approach to this work. Additionally, this approach made the synthesis of multifunctional carbon dots cost and energy efficient. Further, the synthesised carbon dots (g-CDs and b-CDs) have been combined with visible light active semiconductor nanoparticles for energy and environmental applications. For the photocatalytic hydrogen generation, being a metal chalcogenide and owing to the energy level considerations required for the photocatalytic hydrogen generation, CdS nanoparticles had been used as the parent semiconductor. An elevated hydrogen generation rate of 1582 and#956;molg-1 H2 gas with a 6.37% apparent quantum yield is obtained for the b-CDsatCdS-6 system. For the waste water treatment in this study, WO3 nanoparticles have been chosen as the parent semiconductor. The adsorption technique was utilized for heavy metal removal, Cd (II) ions using g-CDs modified WO3 nanoparticles as catalyst. newline