Graphitic Carbon Nitride (g-C3N4) Based Heterostructur Matters for Photocatalytic Environmental Applications under Natural Sunlight Illumination

Abstract

An imminent threat of heightened environmental pollution is due to expanding and the rise of modern industries. Among the most pressing issues is water contamination from diverse pollutants, highlighting an urgent need for sustainable freshwater resources. Moreover, the ubiquitous presence of organic and inorganic pollutants in wastewater from various industries causes significant environmental damage. So, the shortage of fresh water and water pollution has become a global concern. To address these concerns, visible-light-driven photocatalysis is considered as a promising green technique capable of effectively degrading organic and inorganic contaminants into environmentally friendly products. The metal-free polymeric semiconductor g-C3N4 has been demonstrated to be one of the ideal compounds for environmental application because of its conjugated structure, non-toxicity, and cheap cost. Therefore, in this doctorate dissertation, an attempt has been made to investigate the development of distinct g-C3N4-based improved photocatalytic matters that may be employed for environmental pollution remediation. A thorough characterization was conducted to comprehend the fundamental, optical, morphological, and photoelectrochemical features of the synthesized heterojunction matters. The photocatalytic apply of the developed heterostructure matters were tested for photodegradation of organic (dyes) and inorganic (heavy metals) pollutants. In the first scenario, g-C3N4/metal-oxide heterojunction nanocomposites, i.e., heterojunction of graphitic carbon nitride with zirconium oxide (g-C3N4/ZrO2), were effectively developed via an ultra-sonication process and were discovered to have outstanding capabilities for rhodamine B dye degradation. In our second scenario, we attempted to build g-C3N4/metal sulfide heterojunction systems, namely hexagonal CuS coupled with g-C3N4 layer (g-C3N4/CuS) by in-situ hydrothermal approach, which were shown to have outstanding visible-light (sunlight) photocatalytic proficiency against various organic dye (mainly methyl orange and methylene blue) degradation. In final scenario, successfully produced a g-C3N4/metal oxy-halide system, i.e., a graphitic carbon nitride linked BiOBr nanoplate heterojunction (g-C3N4/BiOBr) with increased photocatalytic activity for dye degradation (rhodamine B and methylene blue) and Cr(VI) reduction. To comprehend the mechanism behind photocatalytic proficiency, thorough mechanistic studies as well as band structure studies of the all developed matters were carried out. Ultimately, the work reported in this thesis demonstrates the potential for effective photocatalysis in environmental applications involving visible-light (sunlight) active graphitic carbon nitride nanomaterials.