In this work, pure ZnO, SnO₂, and ZnO‐SnO₂ nanostructured composites (Z‐S heterostructure) are fabricated by a facile and environmental savvy hydrothermal method at 230°C for 12 hours and followed by high‐temperature annealing. The synthesized samples were examined to analyse the structural and optical characteristics using XRD, TEM, XPS, and UV‐DRS techniques. Investigate the photocatalytic activity (PCA) of pure ZnO, SnO₂, and Z‐S heterostructure for the decolorization of methylene blue (MB) model pollutant in wastewater using visible light irradiation. XRD analysis reveals that ZnO and SnO₂ exhibit hexagonal wurtzite structure and tetragonal rutile structure. TEM micrographs infer the nanorod‐like structure of ZnO, nanoflake‐like structure of SnO₂, and a thin nanosheet‐like structure of Z‐S. XPS analysis evidence for the presence of constitutes elements and Zn⁺², Sn⁺², O⁻² valance states along with environmental peaks in Z‐S heterostructure. The optical band gaps of ZnO (3.37 eV), SnO₂ (3.6 eV), and Z‐S heterostructure (2.84 eV) are inferred by UV‐DRS analysis, together with evidence for the red shift. Under two hours of visible light illumination, the photocatalytic degradation efficiency of MB dye in pure ZnO, SnO₂, and Z‐S heterostructure is 38.55, 32.68, and 82.45%. The formation of a unique Z‐S heterostructure and the maximum departure of charge carriers are the reasons for obtaining robust degradation activity than pristine ZnO and SnO₂. MB dye degradation process in the presence of Z‐S heterostructure photocatalyst, the reusability test findings, and the suggested charge separation technique for customizing Z‐S heterostructure photocatalyst under visible light irradiation is presented.

Using a hydrothermal synthesis process, Fe-doped ZnO/SnS nanostructures were created and a variety of analytical methods were used to describe their characteristics. X-ray diffraction patterns were employed to confirm the hexagonal and orthorhombic crystal structures of ZnO and SnS, respectively. Nanorods and nanoparticle clouds were visible in TEM pictures, and XPS investigation verified that the dopant Fe ions were in the 3+ oxidation state. Additionally, absorption spectroscopy revealed a decrease in the energy bandgap with an increase in Fe content, and photoluminescence analysis demonstrated that the ZSF3 sample significantly reduced the rate of recombination of charge carriers. Impressively, the optimized sample (ZSF3) displayed 95.8% more photocatalytic activity during the 120 min degradation of MB dye. This study demonstrated that an easy hydrothermal procedure, carried out at 220°C for 12 hours, may be used to create iron-doped ZnO/SnS nanocomposites. The tunable energy bandgap characteristics of heterogeneous semiconducting materials and the effective charge carrier separation were thought to be the causes of the increased photocatalytic activity. Furthermore, the heterostructure of charge carriers was proposed to facilitate photocatalytic activity when exposed to light.

Global environmental contamination will worsen, requiring innovative solutions based on cutting‐edge research. Photocatalysis has advanced in recent years by using metal sulfide quantum dots (QDs), graphitic carbon nitride (g‐CN), and their nanocomposite heterojunctions. This systematic study examined the latest developments in this revolutionary area. The article begins by describing metal sulfide QDs and the optical, electrical, and structural characteristics of metal sulfide QDs and g‐CN. Appreciating the tremendous potential of these materials to solve environmental issues begins with these realizations. The major attraction, nanocomposite heterojunctions, was next examined. We examine the fascinating world of g‐CN–metal sulfide QD composites, including their synthesis, cooperative behavior, and heterojunction topologies such as Type I, Type II, Zscheme, and S‐scheme. These heterojunctions unlock the photocatalytic efficiency hitherto unreachable. We learn how these heterostructures boost photocatalytic efficiency, revealing their revolutionary potential. This review shows how these advances are used in real life. These materials have accelerated the shift toward a cleaner, sustainable future by degrading organic contaminants and converting CO ₂ into useful compounds.

Copper-modified phosphotungstic acid (CuPW) supported on titania materials with various CuPW contents were successfully synthesized by ion exchange followed by an impregnation method. The prepared materials were characterized using XRD, Raman, ammonia TPD, pyridine FT-IR spectroscopy, and BET-surface area measurements. The XRD results revealed that the crystalites of Keggin ions of heteropolyacid were merged with the anatase support. The Raman spectroscopy results of the fresh and regenerated 30 wt% CuPW/TiO₂ clearly showed the characteristic peak of Keggin ions being intact with the support. The results from the temperature-programmed desorption (TPD) of ammonia tests revealed that a 30 wt% catalyst possessed a greater number of acidic sites than the other loadings. Pyridine-adsorbed FT-IR spectroscopy suggested that the 30 wt% catalyst calcined at 300 °C had high amount of Lewis and Brønsted acidity. The copper-modified phosphotungstic acid on the titania support significantly altered the Brønsted and Lewis acidity of the catalysts and promoted a remarkable catalytic performance during glycerol carbonylation as well as provided related structural and acidity functionalities to the CuPW/TiO₂ catalyst.