Synthesis of Bismuth-based Nanocomposites for Hydrogen Generation and Degradation of Organic Pollutants

Abstract

This present thesis work includes the fabrication of various mole ratios of 5 different sunlight driven photocatalysts i.e., BiVO4/MoSe2, BiVO4/SnS2, BiVO4/BiOBr, BiVO4/WO3, and BiVO4/Sb2S3 by hydrothermal route. The synthesized heterojunction photocatalysts possessed a high surface area, narrow band gap, lower recombination rate and good carrier charge transport ability than their bare components. One of the important characteristics of these photocatalysts is their good reusability and high stability. Thus, these photocatalysts can be effectively used multiple times without significant deterioration in their performance. The performance of the fabricated photocatalysts was gauged by conducting the photocatalytic degradation studies for the different pharmaceutical contaminants, and PEC water splitting. The impact of pH of the solution, concentration of the photocatalyst, influence of different light sources was all studied for the photodegradation process. Quenching experiment was also performed to understand the role of active radical species responsible for the degradation of the pollutant. The reusability studies were conducted of the synthesized photocatalysts to establish their practical utility. Also, post degradation XRD, SEM, and BET were carried out to know the stability of the photocatalysts. For the PEC water splitting studies different experiments for e.g., LSV, EIS, chronoamperometry, and Mott-Schottky were carried out. Lastly stability study was conducted to assess the stability of the electrode and quantify hydrogen evolution rate. The outcomes revealed that the heterojunction photocatalysts exhibited good efficiency compared to the corresponding bare ones. This can be attributed to their higher surface area, increased number of active sites, lower recombination rate, and good charge migration ability to promote high reaction kinetics. The fabricate heterojunction photocatalysts can be efficiently utilized for the decomposition of the various organic pollutants present in the wastewater and for PEC water splitting to evolve the hydrogen.