Biogenic synthesis of iron oxide nanoparticles using Soymida febrifuga bark extract: characterization, antibacterial, and antioxidant evaluation G. Vimala, Kishore Mendam, B. Uma, N.R. Rajagopalan, Channamsetti Sushma, Parveen Sharma, Nellore Manoj Kumar, G.R. Satyanarayana Results in Chemistry, 2026 This study aimed to develop an eco-friendly approach for the synthesis of iron oxide nanoparticles using an aqueous bark extract of Soymida febrifuga as a reducing and stabilizing agent and to evaluate their physicochemical and biological properties. The Phytosynthesized nanoparticles were characterized using UV–visible spectroscopy, XRD, FT-IR, SEM, and EDAX analyses. XRD confirmed the crystalline nature of the iron oxide nanoparticles with an average crystallite size of approximately 90 nm, while FT-IR analysis indicated the involvement of phenolic and hydroxyl functional groups in nanoparticle stabilization. SEM analysis revealed polyhedral morphology with uniform distribution, and EDAX confirmed the elemental composition of iron and oxygen. The synthesized nanoparticles exhibited significant antibacterial activity against Clavibacter michiganensis, Enterococcus faecium, Escherichia coli, and Pseudomonas aeruginosa , with the highest inhibition observed against P. aeruginosa at higher concentrations. In addition, the nanoparticles demonstrated concentration-dependent antioxidant activity in DPPH, Phosphomolybdenum, and hydrogen peroxide scavenging assays, outperforming the crude plant extract. These findings highlight the dual antibacterial and antioxidant potential of S. febrifuga -mediated iron oxide nanoparticles and support their relevance for future biomedical and environmental applications, warranting further mechanistic and biocompatibility investigations.
Emerging applications of sustainable modified CdO/Ag-CdO NPs for electrochemical sensitive and selective detection of mercury (Hg+) heavy metal B. S. Surendra, H. N. Sowmya, T. Kiran, M. Bhaskar, Shwetha Rajappa, B. Uma, Syed Khasim, H. C. Ananda Murthy, K. Y. Chan Scientific Reports, 2025 The sensitivity of developed electrode has gained significant attention for potential energy storage and electrochemical sensor activities. The modified nano-CdO/Ag-CdO-carbon paste electrodes were developed for electrochemical detection of mercury (Hg + ) heavy metal. The synthesized samples were well characterized through PXRD (Powder X-ray diffraction), SEM-EDAX (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis), XPS (X-ray photo-electron spectroscopy), FT-IR (Fourier transform Infra-Red), and UV-Visible spectroscopy. The Ag-CdO modified electrode endowed with higher sensing current and Csp (188 F/g) than pure CdO NPs (94.6 F/g) measured by Linear Sweep (LS), Cyclic Voltammetric (CV) and Electrochemical Impedance Spectral (EIS) techniques. The excellent electrochemical sensing action of developed Ag-CdO electrode was examined on heavy metal Hg + ions at 1–5 mM scan rate in 0.1 M KCl. The linear relationship of sensing measurements with smaller concentration (1–5 mM) was observed with its increased current (+ 1.64 × 10 –4 A/cm 2 at 1 mM) at 30 mV/s. LOD of CdO and Ag-CdO electrodes (Hg + Oxid ) were found at 1.91 mM & 2.41 mM (Hg + Red ) respectively with maximum sensitivity at -0.006 V. LOQ of CdO and Ag-CdO electrodes (Hg + Oxid ) were 5.78 mM & 6.98 mM respectively with maximum sensitivity at -0.006 V. The antibacterial measurements of prepared samples were examined for their susceptibility to inhibit the growth of gram-negative ( Escherichia coli) and gram-positive ( Staphylococcus aureus) bacteria. Thus, the synthesized Ag-CdO electrode provides a new insight for determining the concentrations of critical pollutants and processing the various nanoparticles for sensing of cyanogenic heavy metals.
Simplified electrochemical sensor based on sulphuric acid-preactivated glassy carbon electrode for enhanced detection of 2-nitrophenol and 4-aminopyridine Mayur Uday Karvekar, Kalyan Raj, Malini. S, Supreeth. S, B. Uma, Abhishek Appaji International Journal of Electrochemical Science, 2025 ABSTRACT Steadily increasing water pollutants pose significant health risks; hence, environmental contaminants detection is a societal imperative. In response to growing ecological concerns, electrochemical sensors qualify as environmentally relevant tools. This report presents an electrochemical approach of pre-anodizing with H 2 SO 4 to develop a pre-treated glassy carbon electrode sensor (PGCE) to identify eco-toxic organic pollutants 2-nitrophenol and 4-aminopyridine in water bodies. The suggested process enhanced sensitivity after pretreatment with 1 M H 2 SO 4 and cycling from -0.4 V to +2.0 V over 20 cycles. The electrochemical characteristics of the aforesaid pollutants were analyzed individually through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods and compared with the data obtained using an unmodified bare glassy carbon electrode (BGCE). An enhancement of the cyclic voltammetric response of well-defined anodic and cathodic peaks at 0.66 V and 0.31 V, respectively, for 2-nitrophenol and only an anodic peak at -0.60 V for 4-aminopyridine was observed. For both the pollutants, the peak current elevated with increasing concentration from 0.25 to 1.00 µM and scan rate varied from 10-50 mVs-1, indicating diffusion-controlled electrode activity. Through DPV, the limit of detection (LOD) for 2-nitrophenol was 3.46 µM, and the limit of quantification (LOQ) was reported to be 10.49 µM, whereas LOD and LOQ were 0.89 µM and 2.70 µM, respectively, for 4-aminopyridine. The reported sensor provides excellent stability, selectivity, reproducibility, and good reactivity towards the detection of organic pollutants and hence finds a good number of applications in environmental studies.
A mini-review on Z and S scheme heterojunction bismuth based photocatalysts towards H2 production, CO2 reduction, and pollutant degradation Arpita Paul Chowdhury, Kurupalya Shivram Anantharaju, Kempaiah Keshavamurthy, Swarnalata Swain, Bogegowda Uma Next Materials, 2025 Using the limitless energy of the sun, photocatalysis offers a sustainable and environmentally friendly way to clean up the environment and store energy. To overcome the drawbacks of traditional heterojunctions in terms of kinetics and thermodynamics, the step-scheme (S-scheme and Z scheme heterojunction was devised. Interestingly, because of their distinct electrical composition and layered architectures, bismuth-based catalysts have been extensively investigated in a variety of applications. Because the valence band of bismuth-based compounds is made up of hybrid orbitals, the band gap is less, making it easier to migrate photogenerated electron-hole pairs. This review's objective is to study the most recent developments and successes in the creation of Bi based S and Z scheme. First, a summary of the basic ideas behind the formation of heterojunctions was provided. Second, the important uses of S and Z scheme heterojunction photocatalysts in the creation of hydrogen, the reduction of CO2, and the degradation of pollutants were covered. Finally, the article provides valuable insights for future research and development involving in the designing and construction of a Bi-based heterojunction.
2D Graphene Materials for Optoelectronic and Photonic Device Applications M. Dinamani, Shashank A. Tidke, B. Uma, G. Vidya Handbook of 2d Materials for A Sustainable Future Volume One, 2025 The prosperity of the optoelectronic properties of graphene has attracted substantial interest. The core properties, including optical transparency, robustness, flexibility, high mobility, and excellent environmental stability of this 2D material, make it a good candidate for optoelectronic applications. Numerous chemical synthesis and preparation methods have been developed to accomplish good quality and large-area graphene. These progressions permit high performance in graphene-associated optoelectronic and photonic devices such as solar cells, light-emitting diodes (LEDs), and optical modulators. This chapter endeavors to review the different types, optical characteristics, and production techniques, followed by research advancements on optoelectronic and photonic devices with graphene.
Visible-Light-Driven Mentha spicata L.-Mediated Ag-Doped Bi2Zr2O7 Nanocomposite for Enhanced Degradation of Organic Pollutants, Electrochemical Sensing, and Antibacterial Applications Kurlla Pompapathi, Kurupalya Shivram Anantharaju, Periyakaruppan Karuppasamy, Meena Subramaniam, Bogegowda Uma, Surendra Boppanahalli Siddegowda, Arpita Paul Chowdhury, H. C. Ananda Murthy ACS Environmental Au, 2024 Novel visible-light-driven Ag (X)-doped Bi2Zr2O7 (BZO) nanocomposites in pudina (P) extract (Mentha spicata L.), X-1, 3, 5, 7, and 9 mol %, were synthesized by the one-pot greener solution combustion method. The as-synthesized nanocomposite materials were characterized by using various spectral [X-ray diffraction (XRD), Fourier transform infrared, UV–visible, UV– diffuse reflectance spectra, X-ray photoelectron spectroscopy], electrochemical (cyclic voltammetry, electrochemical impedance spectroscopy), and analytical (scanning electron microscopy–energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller) techniques. The average particle size of the nanocomposite material was found to be between 14.8 and 39.2 nm by XRD. The well-characterized Ag-doped BZOP nanocomposite materials exhibited enhanced photocatalytic degradation activity toward hazardous dyes such as methylene blue (MB) and rose bengal (RB) under visible light irradiation ranges between 400 and 800 nm due to their low energy band gap. As a result, 7 mol % of Ag-doped BZOP nanocomposite material exhibited excellent photodegradation activity against MB (D.E. = 98.7%) and RB (D.E. = 99.3%) as compared to other Ag-doped BZOP nanocomposite materials and pure BZOP nanocomposite, respectively, due to enhanced semiconducting and optical behaviors, high binding energy, and mechanical and thermal stabilities. The Ag-doped BZOP nanocomposite material-based electrochemical sensor showed good sensing ability toward the determination of lead nitrate and dextrose with the lowest limit of detection (LOD) of 18 μM and 12 μM, respectively. Furthermore, as a result of the initial antibacterial screening study, the Ag-doped BZOP nanocomposite material was found to be more effective against Gram-negative bacteria (Escherichia coli) as compared to Gram-positive (Staphylococcus aureus) bacteria. The scavenger study reveals that radicals such as O2•– and •OH are responsible for MB and RB mineralization. TOC removal percentages were found to be 96.8 and 98.5% for MB and RB dyes, and experimental data reveal that the Ag-doped BZOP enhances the radical (O2•– and •OH) formation and MB and RB degradation under visible-light irradiation.
Vacuum impregnated silver–halloysite nanocomposites for the electrochemical detection of dopamine and uric acid SP Nayak, JKK Kumar, B Uma, SS Ramamurthy Ionics, 1-12 , 2026 2026
Biogenic synthesis of iron oxide nanoparticles using Soymida febrifuga bark extract: characterization, antibacterial, and antioxidant evaluation G. Vimala , Kishore Mendam , B. Uma , N.R. Rajagopalan , Channamsetti Sushma ... Results in Chemistry 22, 103115 , 2026 2026
An effective sensing platform of graphite-based Zr-CdFe2O4 nanoparticle for electrochemical sensing of heavy metal Pb2+ ions and Sunlight-induced photo-degradation activity SKSR K. N. Harish, Surendra B.S, Uma B, Pavitra Gopalkrishna Pai, Jagadeesh N. M Journal of Materials Science: Materials in Electronics 37, 262 , 2026 2026 Citations: 3
2D Graphene Materials for Optoelectronic and Photonic Device Applications. GV M Dinamani, Shashank A.Tidke, B Uma Handbook of 2D Materials for a Sustainable Future, 412 , 2025 2025
Bio-utilization Synthesis of Fe Doped Bismuth Zirconate Mediated by Menthaspicata L . for Photocatalytic, Antibacterial and Electrochemical Applications K Pompapathi, KS Anantharaju, S Meena, BS Surendra, B Uma, ... Topics in Catalysis, 1-21 , 2025 2025 Citations: 1
Simplified electrochemical sensor based on sulphuric acid-preactivated glassy carbon electrode for enhanced detection of 2-nitrophenol and 4-aminopyridine AA Mayur Uday Karvekar , Kalyan Raj , Malini. S , Supreeth. S , B. Uma International Journal of Electrochemical Science 20 (11) , 2025 2025 Citations: 2
Emerging applications of sustainable modified CdO/Ag-CdO NPs for electrochemical sensitive and selective detection of mercury (Hg + ) heavy metal BS Surendra, HN Sowmya, T Kiran, M Bhaskar, S Rajappa, B Uma, ... Scientific Reports 15 (1), 28200 , 2025 2025 Citations: 10
A mini-review on Z and S scheme heterojunction bismuth based photocatalysts towards H2 production, CO2 reduction, and pollutant degradation AP Chowdhury, KS Anantharaju, K Keshavamurthy, S Swain, B Uma Next Materials 8, 100918 , 2025 2025 Citations: 22
fFabrication of Zirconia-doped Cu 2 O/CuO/Cu hetero-nanocomposite: Enhanced electrochemical sensor, antibacterial and photocatalytic activity B Uma, KS Anantharaju, BS Surendra, AP Chowdhury, S Khasim, ... Ionics 31 (5), 5067-5084 , 2025 2025 Citations: 11
Exploring the spectroscopic, optical, dielectric, and hardness properties of L-histidine methylester dihydrochloride (LHMEDH), a nonlinear optical compound for optoelectronic uses HMAPDGNMKDNPRIBUMPMCA Gonsago Applied Physics A 130 , 2024 2024 Citations: 2
Visible-Light-Driven Mentha spicata L.-Mediated Ag-Doped Bi 2 Zr 2 O 7 Nanocomposite for Enhanced Degradation of Organic Pollutants, Electrochemical Sensing … K Pompapathi, KS Anantharaju, P Karuppasamy, M Subramaniam, ... ACS Environmental Au 4 (2), 106-125 , 2024 2024 Citations: 53
Sustainable approach of La doped CuFe 2 O 4 nanomaterial for electrochemical lead and paracetamol sensing action with multiple applications M Giridhar, BC Manjunath, BS Surendra, KN Harish, SC Prashantha, ... Scientific Reports 13 (1), 17821 , 2023 2023 Citations: 31
Influence of Ag on the Structural, Electrochemical, Antibacterial, and Photocatalytic Performance of the (CuO–Cu 2 O)Cu Nanocomposite B Uma, KS Anantharaju, BS Surendra, K Gurushantha, SS More, ... ACS omega 8 (11), 9947-9961 , 2023 2023 Citations: 46
Green-engineered synthesis of Bi2Zr2O7 NPs: excellent performance on electrochemical sensor and sunlight-driven photocatalytic studies APCRLN Pompapathi Kurlla, Anantharaju Kurupalya Shivram, Nagaraju Kottam ... Environmental Science and Pollution Research , 2023 2023 Citations: 21
Synergistic effect of a Bi 2 Zr 2 O 7 and hydroxyapatite composite: organic pollutant remediation, antibacterial and electrochemical sensing applications K Pompapathi, KS Anantharaju, BS Surendra, S Meena, B Uma, ... RSC advances 13 (40), 28198-28210 , 2023 2023 Citations: 17
Synthesis of novel heterostructured Fe-doped Cu2O/CuO/Cu nanocomposite: Enhanced sunlight driven photocatalytic activity, antibacterial and supercapacitor properties B Uma, KS Anantharaju, S Malini, SS More, YS Vidya, S Meena, ... Ceramics International 48 (23), 35834-35847 , 2022 2022 Citations: 40
Enhanced sunlight driven photocatalytic activity and electrochemical sensing properties of Ce-doped MnFe2O4 nano magnetic ferrites S Meena, KS Anantharaju, YS Vidya, L Renuka, B Uma, SC Sharma, ... Ceramics International 47 (10), 14760-14774 , 2021 2021 Citations: 94
Synthesis of CuO samples by co-precipitation and green mediated combustion routes: Comparison of their structural, optical properties, photocatalytic, antibacterial, haemolytic … B Uma, KS Anantharaju, L Renuka, S Malini, SS More, YS Vidya, ... Ceramics International 47 (7), 10355-10369 , 2021 2021 Citations: 52
Controlled synthesis of (CuO-Cu2O)Cu/ZnO multi oxide nanocomposites by facile combustion route: A potential photocatalytic, antimicrobial and anticancer activity SM B. Uma, K.S. Anantha raju, L.Renuka, , H. Nagabhushana, S. Malini, Sunil ... Ceramic International , 2020 2020 Citations: 69
Porous network ZrO2/ZnFe2O4 nanocomposite with heterojunction towards industrial water purification under sunlight: Enhanced charge separation and elucidation of photo-mechanism PK L.Renuka, K.S. Anantha raju, Y.S.Vidya, H. Nagabhushana, B.Uma, S. Malini ... Ceramic International , 2020 2020 Citations: 31
MOST CITED SCHOLAR PUBLICATIONS
Enhanced sunlight driven photocatalytic activity and electrochemical sensing properties of Ce-doped MnFe2O4 nano magnetic ferrites S Meena, KS Anantharaju, YS Vidya, L Renuka, B Uma, SC Sharma, ... Ceramics International 47 (10), 14760-14774 , 2021 2021 Citations: 94
Controlled synthesis of (CuO-Cu2O)Cu/ZnO multi oxide nanocomposites by facile combustion route: A potential photocatalytic, antimicrobial and anticancer activity SM B. Uma, K.S. Anantha raju, L.Renuka, , H. Nagabhushana, S. Malini, Sunil ... Ceramic International , 2020 2020 Citations: 69
Visible-Light-Driven Mentha spicata L.-Mediated Ag-Doped Bi 2 Zr 2 O 7 Nanocomposite for Enhanced Degradation of Organic Pollutants, Electrochemical Sensing … K Pompapathi, KS Anantharaju, P Karuppasamy, M Subramaniam, ... ACS Environmental Au 4 (2), 106-125 , 2024 2024 Citations: 53
Synthesis of CuO samples by co-precipitation and green mediated combustion routes: Comparison of their structural, optical properties, photocatalytic, antibacterial, haemolytic … B Uma, KS Anantharaju, L Renuka, S Malini, SS More, YS Vidya, ... Ceramics International 47 (7), 10355-10369 , 2021 2021 Citations: 52
Influence of Ag on the Structural, Electrochemical, Antibacterial, and Photocatalytic Performance of the (CuO–Cu 2 O)Cu Nanocomposite B Uma, KS Anantharaju, BS Surendra, K Gurushantha, SS More, ... ACS omega 8 (11), 9947-9961 , 2023 2023 Citations: 46
Synthesis of novel heterostructured Fe-doped Cu2O/CuO/Cu nanocomposite: Enhanced sunlight driven photocatalytic activity, antibacterial and supercapacitor properties B Uma, KS Anantharaju, S Malini, SS More, YS Vidya, S Meena, ... Ceramics International 48 (23), 35834-35847 , 2022 2022 Citations: 40
Sustainable approach of La doped CuFe 2 O 4 nanomaterial for electrochemical lead and paracetamol sensing action with multiple applications M Giridhar, BC Manjunath, BS Surendra, KN Harish, SC Prashantha, ... Scientific Reports 13 (1), 17821 , 2023 2023 Citations: 31
Porous network ZrO2/ZnFe2O4 nanocomposite with heterojunction towards industrial water purification under sunlight: Enhanced charge separation and elucidation of photo-mechanism PK L.Renuka, K.S. Anantha raju, Y.S.Vidya, H. Nagabhushana, B.Uma, S. Malini ... Ceramic International , 2020 2020 Citations: 31
A mini-review on Z and S scheme heterojunction bismuth based photocatalysts towards H2 production, CO2 reduction, and pollutant degradation AP Chowdhury, KS Anantharaju, K Keshavamurthy, S Swain, B Uma Next Materials 8, 100918 , 2025 2025 Citations: 22
Green-engineered synthesis of Bi2Zr2O7 NPs: excellent performance on electrochemical sensor and sunlight-driven photocatalytic studies APCRLN Pompapathi Kurlla, Anantharaju Kurupalya Shivram, Nagaraju Kottam ... Environmental Science and Pollution Research , 2023 2023 Citations: 21
Synergistic effect of a Bi 2 Zr 2 O 7 and hydroxyapatite composite: organic pollutant remediation, antibacterial and electrochemical sensing applications K Pompapathi, KS Anantharaju, BS Surendra, S Meena, B Uma, ... RSC advances 13 (40), 28198-28210 , 2023 2023 Citations: 17
fFabrication of Zirconia-doped Cu 2 O/CuO/Cu hetero-nanocomposite: Enhanced electrochemical sensor, antibacterial and photocatalytic activity B Uma, KS Anantharaju, BS Surendra, AP Chowdhury, S Khasim, ... Ionics 31 (5), 5067-5084 , 2025 2025 Citations: 11
Emerging applications of sustainable modified CdO/Ag-CdO NPs for electrochemical sensitive and selective detection of mercury (Hg + ) heavy metal BS Surendra, HN Sowmya, T Kiran, M Bhaskar, S Rajappa, B Uma, ... Scientific Reports 15 (1), 28200 , 2025 2025 Citations: 10
An effective sensing platform of graphite-based Zr-CdFe2O4 nanoparticle for electrochemical sensing of heavy metal Pb2+ ions and Sunlight-induced photo-degradation activity SKSR K. N. Harish, Surendra B.S, Uma B, Pavitra Gopalkrishna Pai, Jagadeesh N. M Journal of Materials Science: Materials in Electronics 37, 262 , 2026 2026 Citations: 3
Simplified electrochemical sensor based on sulphuric acid-preactivated glassy carbon electrode for enhanced detection of 2-nitrophenol and 4-aminopyridine AA Mayur Uday Karvekar , Kalyan Raj , Malini. S , Supreeth. S , B. Uma International Journal of Electrochemical Science 20 (11) , 2025 2025 Citations: 2
Exploring the spectroscopic, optical, dielectric, and hardness properties of L-histidine methylester dihydrochloride (LHMEDH), a nonlinear optical compound for optoelectronic uses HMAPDGNMKDNPRIBUMPMCA Gonsago Applied Physics A 130 , 2024 2024 Citations: 2
Bio-utilization Synthesis of Fe Doped Bismuth Zirconate Mediated by Menthaspicata L . for Photocatalytic, Antibacterial and Electrochemical Applications K Pompapathi, KS Anantharaju, S Meena, BS Surendra, B Uma, ... Topics in Catalysis, 1-21 , 2025 2025 Citations: 1
Vacuum impregnated silver–halloysite nanocomposites for the electrochemical detection of dopamine and uric acid SP Nayak, JKK Kumar, B Uma, SS Ramamurthy Ionics, 1-12 , 2026 2026
Biogenic synthesis of iron oxide nanoparticles using Soymida febrifuga bark extract: characterization, antibacterial, and antioxidant evaluation G. Vimala , Kishore Mendam , B. Uma , N.R. Rajagopalan , Channamsetti Sushma ... Results in Chemistry 22, 103115 , 2026 2026
2D Graphene Materials for Optoelectronic and Photonic Device Applications. GV M Dinamani, Shashank A.Tidke, B Uma Handbook of 2D Materials for a Sustainable Future, 412 , 2025 2025