Raja Doraisingam Government Arts College

Developing high-performing photocatalysts and composites generate synergetic effects in modern photocatalysis. Zinc oxide (ZnO) is a promising photocatalyst; however, its wide bandgap and high charge carrier recombination rate significantly limit its visible-light activity and overall photocatalytic efficiency. To overcome these challenges, this study focuses on the synthesis of Cu-Ag codoped ZnO/graphene nanocomposites using both hydrothermal and sonochemical methods, aiming to regulate the interfacial interaction and enhance charge separation. The hydrothermally synthesized (CAZ/Gr)H composite exhibited a lower bandgap, improved carrier transfer efficiency, and stronger Zn-O-C interfacial bonding compared to the sonochemically prepared (CAZ/Gr)S sample. Density functional theory (DFT) calculations confirmed the reduced work function and enhanced electron mobility in the hydrothermal system. Under natural sunlight, the (CAZ/Gr)H composite demonstrated superior photocatalytic degradation of organic dyes and excellent antibacterial activity against E. coli and S. aureus. These findings highlight the effectiveness of interface-regulated, green-synthesized ZnO-based nanocomposites in addressing the fundamental limitations of traditional ZnO photocatalysts.

Photocatalytic hydrogen generation has emerged as a strategically significant route toward sustainable and carbon-neutral energy conversion. Titanium dioxide (TiO2) remains the most extensively studied photocatalyst, valued for its physicochemical robustness, abundance, and environmental compatibility. Nonetheless, its intrinsic wide band gap restricts solar energy utilization to the ultraviolet spectrum, severely constraining overall quantum efficiency. Non-metal doping strategies employing elements such as nitrogen, sulfur, and boron have been widely explored to narrow the band gap and extend light absorption. While cost-effective and environmentally benign, these modifications frequently introduce shallow trap states, accelerate electron–hole recombination, and fail to sustain efficient charge separation, thereby limiting practical performance gains. Conversely, metal doping, particularly with transition and noble metals, has demonstrated superior control over charge carrier dynamics, recombination suppression, and catalytic activity. Co-doping approaches further provide synergistic enhancements in both light harvesting and charge transport. This review critically evaluates recent advances in metal-doped and theoretically engineered TiO2-based photocatalysts, emphasizing the regulatory role of work function in optimizing activity. It examines underlying mechanisms, performance determinants, and current limitations, while underscoring the transformative potential of computational approaches [density functional theory (DFT), machine learning (ML), and Artificial intelligence (AI)] in guiding rational photocatalyst design for scalable hydrogen production.

Elevated reactive oxygen species (ROS) levels are associated with cancer and inflammation, motivating the development of ROS-responsive drug delivery systems that exploit the oxidative tumor microenvironment for controlled release. Breast cancer remains a major global health challenge, necessitating effective and low-toxicity therapies. Camptothecin (CPT), a potent topoisomerase I inhibitor, is limited clinically by poor solubility and systemic toxicity. In this study, we developed a multifunctional nanocomposite (NIOs/AuNPs-CS/CPT) consisting of CPT-loaded niosomes (NIOs) integrated with chitosan (CS)-coated gold nanoparticles (AuNPs) synthesized via a green method using Moringa oleifera seeds extract. Structural and morphological analyses confirmed successful fabrication. In-vitro release studies revealed pH- and ROS-responsive CPT release under tumor-like conditions. The nanocomposite exhibited strong anti-inflammatory activity (IC50 = 24.10 μg/mL) and enhanced cytotoxicity against MCF-7 breast cancer cells (IC50 = 5.2 ± 0.10 μg/mL), outperforming control formulations. These results highlight its potential as a biocompatible platform for targeted breast cancer therapy.

The present research showcases the synthesis of novel metal complexes including Cu (II), Ni (II), Co (II), VO (II), and Zn (II) derived from Acetyl Acetone-4-Imino-2, 3-Dimethyl-1-Phenyl-3-Pyrazolin-5-One and 2-Aminothiazole. Various analytical techniques such as Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM) for morphological studies, UV–Vis spectroscopy, FT-IR, 1H-NMR spectroscopy, elemental analysis, Electron spin resonance (ESR), and magnetic susceptibility measurements were employed to thoroughly characterize these complexes. The analysis of FT-IR, magnetic susceptibility, and UV–Vis spectra of the complexes suggests a square planar geometry for most, except for the metal complex [VOL]Cl, which exhibits a rectangular pyramidal geometry. Cyclic voltammetry analysis of [VOL]Cl and [CuL]Cl complexes in MeCN reveals that the coordinated ligands play a role in influencing the redox potential of the metal ions. Powder XRD data and SEM images indicate that the composite materials consist of small-sized grains with a polycrystalline structure. This study also explores the antimicrobial properties of novel schiff base metal complexes using biologically active ligands. The complexes exhibit enhanced antimicrobial activity compared to free ligands, as demonstrated by minimum inhibitory concentration (MIC) values against various bacterial and fungal strains. These findings highlight the potential of metal coordination in drug design and set the stage for future investigations into their therapeutic applications.

In this manuscript, we present a facile and friendly sol-gel method to prepare bare and Zn-doped SnO2 nanoparticles and measured the photocatalytic performance of the materials by measuring the degradation of MB dye under UV light irradiation. A variety of analytical techniques were employed to characterize the materials, including X-ray diffraction, UV-Vis spectroscopy, Photoluminescence (PL), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The X-ray diffraction (XRD) analysis reveals the presence of tetragonal SnO2 nanostructures. The average crystallite size of the bare SnO2 nanostructures was found to be 7.4 nm, but the addition of Zn dopant caused the size to increase to 10.5 nm. PL studies shows that the majority of emission energies fell within the SnO2 NPs' band gap, indicating defects related to oxygen vacancies or Sn interstitials. The morphological analysis of SEM exhibits the various forms of SnO2 nanostructures which are densely agglomerate. The photocatalytic activity of the SZ(10) NPs was found to be MB (88 %). The results showed that the Zn doped SnO2 exhibited good photocatalytic activity.