Synergistic Effect SnO₂/g-C₃N₄ Heterojunction Cocatalyst for Photodegradation of Methyl Orange

The increasing environmental impact of dye-contaminated wastewater, particularly from textile industries, necessitates efficient and sustainable treatment methods. This study presents the synergistic combination of SnO₂ NPs and g-C₃N₄ to form SnO₂@g-C₃N₄ heterojunction, designed as natural light responsive photocatalyst for deterioration of methyl orange (MO), a hazardous azo dye. By combining the strong photocatalytic activity of SnO₂ with visible-light absorption capacity of g-C₃N₄, SnO₂@g-C₃N₄ composite was formed utilizing sol–gel process. Structural, compositional, and morphological analyses were performed using XRD, FTIR, SEM, and EDX, confirming the successful integration of SnO₂ nanoparticles (NPs) onto g-C₃N₄ matrix. Factors including contact time and the impact of pH were examined in order to maximize the competence of synthesized SnO₂@g-C₃N₄ composite. Photocatalytic experiments demonstrated superior reduction efficacy of the SnO₂@g-C₃N₄ composite contrasted with its standalone components under various pH conditions, with a maximum degradation of 74% in acidic media and exhibits maximum degradation of 77% within 45 min. Kinetic studies revealed first-order degradation kinetics, highlighting the composite's potential for wastewater remediation. Additionally, the photocatalyst demonstrated excellent stability and reusability, maintaining their performance over four regeneration cycles. The proposed mechanism attributes enhanced activity to efficient charge separation and improved photon-absorbing properties, facilitated by the heterojunction structure. This work underscores the proficiency of SnO₂@g-C₃N₄ composite as an effective photocatalyst for environmental applications.