Ultrasonication-Assisted Synthesis of S-Scheme g-C ₃ N ₄ /GdFeO ₃ Heterostructures for Enhanced Visible-Light Photocatalytic Degradation of Rhodamine B

Water contamination by persistent organic pollutants has become a major environmental concern, creating an urgent need for efficient and sustainable treatment technologies. Visible-light-driven semiconductor photocatalysis offers a promising approach for pollutant degradation; however, its practical efficiency is often limited by rapid recombination of photogenerated charge carriers. In the present study, thermally exfoliated g-C 3 N 4 nanosheets were integrated with GdFeO 3 through an ultrasonication-assisted assembly approach, and the CNNS/GdFO composition was systematically optimized to enhance visible-light photocatalytic performance. The optimized composite achieved approximately 94% rhodamine B (RhB) removal based on the decrease in UV–Vis absorbance after 120 min of visible-light irradiation. The enhanced photocatalytic activity was consistent with a proposed S-scheme charge-transfer mechanism involving h + , O 2 •- , and •OH reactive species. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) studies show that enhanced photocatalytic activity is linked to better separation and reduced recombination of photogenerated electron–hole pairs. These findings open the path for more sustainable industrial practices by emphasizing the advantages of CNNS/GdFO composites in lowering environmental pollution and expanding our understanding of effective visible-light photocatalysts.