Investigation of Ag–ZnO/rGO Hybrid Composite Material as a Photocatalyst for Phenol Degradation in Aqueous Systems Tanawat Imboon, K. Hemkumar, Jeerawan Khumphon, Chaisak Issro, Jarinee Kiang-ia, Viyaporn Krongtong, Veeramani Mangala Gowri, Sirikanjana Thongmee ACS Omega, 2026 High Resolution Image Download MS PowerPoint Slide This study aims to enhance the photocatalytic degradation of phenol under UV light by synthesizing a silver–zinc oxide/reduced graphene oxide (Ag–ZnO/rGO) hybrid composite via a hydrothermal method. Structural and optical characterizations confirmed the successful incorporation of Ag and rGO into the ZnO matrix, leading to improved light absorption and efficient charge separation. Photocatalytic tests revealed that the Ag–ZnO/rGO hybrid composite showed superior activity, degrading 76.16% of phenol in just 12 h, significantly higher than Ag–ZnO (65.66%) and pure ZnO (31.78%). After 24 h, it achieved 98.91% degradation. Kinetic analysis confirmed its enhanced performance, showing the highest pseudo-first-order rate constant ( k = 0.1883 h –1 ) among all samples. This improvement is attributed to the synergistic effects of Ag and rGO, which promote efficient charge separation and faster degradation kinetics. The enhanced photocatalytic efficiency is attributed to the surface plasmon resonance (SPR) effect of Ag nanoparticles (NPs) and the excellent electron transport properties of rGO, which collectively suppress charge carrier recombination. These findings highlight the promising potential of Ag–ZnO/rGO as a high-performance photocatalyst for environmental remediation and wastewater treatment applications.
Construction of Co-Based MOF Loaded with Carboxymethyl Cellulose for the Photocatalytic Degradation of Brilliant Blue and Estimating the Toxicity of the Byproducts Hemkumar K, P Ananthi, Praveen A, Anitha Pius ACS Chemical Health and Safety, 2025 The deterioration of water quality due to human activities remains an inevitable challenge. In this study, we have developed a photocatalytic membrane by integrating carboxymethyl cellulose (CMC) with a cobalt-based metal–organic Framework (Co-MOF). The synthesized materials were thoroughly characterized using advanced analytical techniques, confirming the successful incorporation of CMC with Co-MOF. The photocatalytic efficiency of the fabricated membrane was evaluated for the degradation of brilliant blue dye, achieving an impressive removal rate of approximately 91% under visible light illumination. The degradation experiments were systematically conducted under varying operational conditions, including the pH, initial dye concentration, and catalyst dosage. The degradation and mineralization of the brilliant blue dye were confirmed using UV–vis spectroscopy, LC–MS analysis, and total organic carbon (TOC) measurements. Furthermore, a comprehensive assessment of the toxicity of the degradation byproducts was performed to evaluate their environmental impact.
Fluorescence Resonance Energy Transfer in Gelatin-Based MOF/N-CDs Films for Superior Photodynamic Antibacterial Packaging Materials P. Ananthi, Naveen Raj V, Hemkumar K, Praveen A, Anitha Pius ACS Sustainable Chemistry and Engineering, 2025 Iron-based porphyrin metal–organic frameworks (Fe-PM) are known for their photodynamic microbial inactivation (PDI) in food packaging. However, their limited generation of reactive oxygen species (ROS) reduces their efficiency. In this study, we introduced a fluorescence resonance energy transfer (FRET) pair using nitrogen-doped carbon dots (N-CDs) as the donor and Fe-PM as the acceptor to boost singlet oxygen ( 1 O 2 ) production. Incorporating Fe-PM@N-CDs into a gelatin polymer film significantly enhanced the antibacterial activity against both Gram-positive and Gram-negative bacteria within 10 min under white LED light. Additionally, the gelatin/Fe-PM@CD composite film showed an improved tensile strength of 93.53 MPa, biodegradability of 68%, and preserved fresh green grapes, destroying 97% of the microorganisms and preventing discoloration and water loss for up to 7 days. These findings demonstrate the potential of this composite film for antibacterial food packaging applications.
Investigation of Morphology-Modified Bi2WO6 Nanoparticles with Surface Plasmon Resonance Effect for the Enhanced Photocatalytic Degradation of Organic Dyes: Toxicity Estimation and In Silico Studies K. Hemkumar, G Vignesh, Pius Anitha ACS Applied Nano Materials, 2024 The advanced oxidation process involves photocatalytic degradation, which is a propitious method of treating wastewater. However, to augment the photocatalytic activity of photocatalysts, the surface plasmon resonance (SPR) method is a highly promising candidate. Herein, we prepared bismuth (Bi) and tungsten (W)-based metal oxide (Bi 2 WO 6 ) coupled with Ag as a semiconducting metal oxide-based plasmon resonance photocatalyst. Despite the SPR effect, the aggregation of particles lowers the efficiency of degradation. To get the better of it, morphology tuning agents and visible light-absorbing agents like CTAB (cetyltrimethylammonium bromide) were used. The prepared composite materials were characterized using sophisticated analytical instruments. The prepared materials were tested for their catalytic activity against Victoria Blue (VB) and Auramine O (AO) dyes. The composite material showed superior catalytic activity over the individual material, 97% and 98% for VB and AO, respectively. In addition, the toxicity of the byproducts (mutagenic toxicity, lethal concentration 50 (LC-50), and lethal dose (LD-50)) was estimated, and the detailed DFT interpretations were studied. Finally, a real-time agricultural application using post-treated water was conducted at the Epipremnum aureum plant.
Antibacterial, Biodegradable Polymeric Films Loaded with Co-MOF/ZnS Nanoparticles for Food Packaging and Photo-Degradation Applications P Ananthi, K. Hemkumar, Anitha Pius ACS Food Science and Technology, 2024 Synthetic polymer-based packing films, despite their many advantages, have posed a great threat to the environment and human health. In this work, we aimed to prepare a chitson/agar-based film incorporated with ZnS nanoparticles and Co-MOF. The prepared composite films were characterized using various instrumental techniques. The addition of ZnS nanoparticles acts as an antibacterial agent as well as a semiconductor for dye degradation. The incorporation of Co-MOF enhances the thermal stability, UV-barrier property, and mechanical and antibacterial activities of prepared films. In addition, the prepared films have superior biodegradation properties. Sliced carrot pieces packed in these composite films remain fresh for up to 7 days at room temperature. Moreover, the prepared films have photocatalytic activity against brilliant blue dye with a degradation efficiency of 88.8%.
Fabrication of UiO-66/GCN, a hybrid photocatalyst, for effective degradation of ciprofloxacin, toxicity estimation, and its antibacterial activity K. Hemkumar, P. Ananthi, Anitha Pius Chemical Research in Toxicology, 2024 Fabrication of a metal-organic framework-based photocatalyst has been gaining much interest due to its higher surface area and reasonable band gap, enhancing its photocatalytic activity. This study attempted a facile synthesis of the hybrid photocatalyst UiO-66 doped with graphitic carbon nitride (GCN) by a simple solvothermal method. This composite minimized the drawback related to photogenerated charge transfer and recombination and helped the absorption of visible light. The material was investigated by using various instrumental techniques. In this work, ciprofloxacin (CIP), a fluoroquinolone drug, was chosen as a target micropollutant, and a photodegradation experiment was carried out by using UiO-66, GCN, and UiO-66/GCN under a visible light source, which exhibited 81.85, 69.48, and 93.60% of degradation, respectively. Finally, liquid chromatography mass spectrometry analysis and theoretical computation were carried out to identify the CIP degradation mechanism, and T.E.S.T. software was used to investigate the toxicity of the intermediate products. Apart from photocatalytic activity, the prepared material was also tested for its antibacterial properties against Staphylococcus aureus and Escherichia coli.
New Thermoelectric Material and Devices: Naphthol[1,3]oxazine and the Performance Compared with Bismuth Telluride Manikandan Subramani, Sivakami Mohandos, Hiroya Ikeda, Lakshmi Prabha Chandrasekar, BharaniDharan Sethuraman, Pandiyarasan Veluswamy, K. Hemkumar ACS Sustainable Chemistry and Engineering, 2024 Herein, we have developed a state-of-the-art approach toward an organic thermoelectric (OTE) device by synthesizing oxazine monomers 2-phenyl-2,3-dihydro-1 H -naphtho[1,2- e ][1,3]oxazine (MNA) and 2-(furan-2-ylmethyl)-2,3-dihydro-1 H -naphthol[1,2- e ][1,3]oxazine (MNF) which were further developed into their ring-opening polymers (PNA and PNF) and found to exhibit the same carrier charges as that of their corresponding monomers. The synthesized organic monomer and polymers have shown significant influence through fabrication to the thermoelectric device by a parallel leg made of synthesized PANi-FeCl 3 /PAN p-type and n-type doped bismuth telluride (Bi 2 Te 3 ) composites and produced the attracting thermoelectric output. The striking hint is that the monomer shows high resistivity and low mobility. In contrast, after the ring-opening polymerization, it demands the attractive notice of the poly naphthoxazine for thermoelectric studies. This novel approach ensures the route to produce a substantial average Seebeck coefficient of 646.70 μV K –1 and power factor 10 × 10 5 W m –1 K –2 and it was revealed that polymer PNA had a greater affinity toward OTE. Further, the p-type and n-type device fabrication of the monomer and the polymer was made using the p-type and n-type doped Bi 2 Te 3, where the p-type PNA shows the highest output of 5.6 mV with PANi-FeCl 3 /PAN n-type doped Bi 2 Te 3 .
