Fabrication of Z-scheme ZnO/g-C3N4/ZnS nanocomposites using high power laser for methylene blue degradation

Abstract

Photocatalysis plays a vital role in addressing environmental challenges by harnessing solar energy for efficient pollutant degradation. In this study, we investigate the photocatalytic activity of a ZnO/g-C _3 N _4 /ZnS composite system in the degradation of methylene blue, a widely used dye with detrimental effects on aquatic ecosystems. The composite materials were synthesized using a facile and scalable approach, and their structural properties, morphologies, sizes, and elemental compositions were characterized using different analytical techniques. The ZnO/g-C _3 N _4 /ZnS composite exhibited enhanced photocatalytic performance compared to individual components. Remarkably, the degradation efficiency reached 80% for the composite with a 30% ZnO composition, surpassing the efficiencies of ZnS alone (29%) and ZnS/g-C _3 N _4 (65%). The composite’s higher degradation efficiency is due to synergistic semiconductor effects, enhancing charge transfer and reducing electron–hole recombination. ZnO incorporation increases active sites and surface area, improving interaction with methylene blue. The favorable band edge positions of ZnO aligned with ZnS and g-C _3 N _4 , facilitating the utilization of a broader spectrum of solar light. The composite’s photocatalytic activity was achieved under UV light irradiation, demonstrating its potential for sustainable and energy-efficient applications. This study highlights the significance of composite design and the Z-scheme concept in photocatalysis, offering insights into the development of advanced materials for environmental remediation. The findings contribute to the understanding of efficient solar-driven pollutant degradation and pave the way for the design and optimization of innovative photocatalytic systems for sustainable environmental solutions.

Keywords

• photocatalysis
• methylene blue
• zinc oxide
• graphite nitrite
• zinc sulphide
• z-scheme