Sunlight-active, S-g-C₃N₄ boosts Ni-doped ZnFe₂O₄ photocatalysts for efficient organic pollutants degradation

The advanced oxidation process (AOP) using heterogeneous photocatalysis has been recognized as an effective method for wastewater treatment. Cubic spinel nickel-doped zinc ferrite (Ni@ZnFe₂O₄) nanoparticles were prepared using hydrothermal synthesis with varying nickel concentrations (0, 1, 3, 5, 7, and 9 wt %). The nanoparticles and nanocomposites were characterized using XRD, XPS, BET, SEM, PL, TEM, UV–visible spectroscopy and FTIR. Ni@ZnFe₂O₄ photocatalyst's ability to degrade dye was tested using Methylene blue (MB) as a probe. The 5 % Ni@ZnFe₂O₄ nanoparticles showed the best photocatalytic efficiency. S@g-C₃N₄ was constructed using thiourea. To further improve catalytic activity, nanocomposites were made with 5 % Ni@ZnFe₂O₄ and varying contents of S@g-C₃N₄ (30, 10, 50, and 70 %). The impact of S@g-C₃N₄ content on photocatalytic performance was observed. The 50 % S@g-C₃N₄/5 %Ni@ZnFe₂O₄ composite performed best among the samples tested. Its enriched photocatalytic capability is due to synergistic exchanges at the S@g-C₃N₄/Ni@ZnFe₂O₄ interface, facilitating more efficient separation and movement of photogenerated charges. Degradation of MB suggests this material may have applications for water purification.