Browsing by Author "Rao, L."

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Bi-functional LaMxFe1-xO3 (M = Cu, Co, Ni) for photo-fenton degradation of methylene blue and photoelectrochemical water splitting
(Elsevier Ltd, 2023) James, A.; Rodney, J.D.; Rao, L.; Badekai Ramachandra, B.R.; Udayashankar, N.K.
Due to growing concern over environmental remediation and the energy crisis, perovskite nanoparticles have gained wide interest in converting solar energy to sustainable fuel and also in degrading organic effluents. Herein, we report the synthesis and bi-functional activity of one-pot-glycine combustion derived LaMxFe1-xO3 (M = Cu, Co, Ni; x = 0, 0.01) for photo-Fenton degradation of Methylene Blue (MB) and photoelectrochemical water splitting. When used as a photocatalyst, with partial substitution of Cu even at a lower concentration, LaCu0.01Fe0.99O3 has exhibited excellent degradation efficiency of 96.4% in 90 min, which is 2.5 times better than the LaFeO3. On the other hand, Co and Ni modified LaFeO3 photocatalysts have demonstrated prominent activities with degradation efficiency of 93.8% and 74.8% respectively within 180 min of visible light irradiation. The retention and reusability analysis showed that LaCu0.01Fe0.99O3 is stable against photo corrosion and remains unchanged after 5 consecutive cycles of MB dye degradation. In addition, LaCu0.01Fe0.99O3 is complimented as a single catalyst for dual functions such as photocatalysis and electrocatalysis, both of which are assisted by visible light. Under illumination, the overpotential (η) improved from 507.6 mV vs RHE (dark) to 498.1 mV vs RHE (light) for O2 evolution and 220.5 mV vs RHE (dark) to 182.8 mV vs RHE (light) for H2 generation respectively. The light response of the catalyst and improvement in activity is validated by the significant enhancement in current density under exposure at both half cycle of chronoamperometry. © 2023 Hydrogen Energy Publications LLC
Cerium-Modulated Zinc Oxide for enhanced Photoelectrochemical Non-Enzymatic biosensing of Cholesterol: An experimental and First Principle Analysis
(Elsevier B.V., 2024) Rao, L.; Rodney, J.D.; Joy, A.; Shivangi Nileshbhai, C.; James, A.; S, S.; Joyline Mascarenhas, F.; Udayashankar, N.K.; Anjukandi, P.; Chul Kim, B.; Badekai Ramachandra, B.R.
Herein, we synthesized CexZn1-xO (x = 0.00, 0.01, 0.02, and 0.03) using the wet chemical method. The investigation explores photoelectrochemical (PEC) biosensors for enzyme-free detection of cholesterol, employing Ce0.03Zn0.97O (CZO3)/Nickel Foam (NF) as the active material. The investigation revealed notable enhancements in sensitivity for cholesterol detection, with a recorded activity of 2.812 mA.mM?1.cm?2, marking a twofold increase in comparison to dark mode (1.37 mA.mM?1.cm?2). The Limit of Detection (LOD) was determined to be 17 µM (light) and 28 µM (dark), while the Limit of Quantification (LOQ) was measured at 54 µM (light) and 98 µM (dark) in 0.1 M KOH solution. These findings demonstrate a linear detection range spanning from 80 µM to 2 mM. Ab-initio calculations based on Density Functional Theory (DFT) were carried out on 101 surfaces of both pristine ZnO and CZO3 to understand how the doping affected the pristine ZnO band gap. The findings indicate that CZO3 exhibits superior activity compared to pristine ZnO, underscoring its enhanced performance and potential for sensing application. The CZO3/NF photoelectrochemical (PEC) biosensor displayed notable cyclic stability, retaining 97 % of its performance over a 60-day period. This underscores its potential for reliable and enduring operation in biosensing applications. Additionally, CZO3/NF exhibited robust sensing capabilities when utilized with human serum samples, showcasing consistent performance in both dark and illuminated conditions. © 2024 Elsevier B.V.
Cobalt-doped LaFeO3 for photo-Fenton degradation of organic pollutants and visible-light-assisted water splitting
(Springer, 2024) James, A.; Rodney, J.D.; Manojbabu, A.; Joshi, S.; Rao, L.; Badekai Ramachandra, B.R.; Udayashankar, N.K.
The increasing demand for clean energy sources and the growing concerns about environmental pollution have led to a significant interest in developing efficient photocatalytic and photoelectrochemical systems. Here, we report the visible-light-induced photo-Fenton catalytic degradation of Methylene Blue (MB) dye over LaFeO3 and LaCo xFe1−xO3 (x = 0.01, 0.05, 0.1) catalysts synthesized via the facile combustion method. The LaCo0.01Fe0.99O3 has significantly enhanced the photo-Fenton catalytic efficiency of LaFeO3 from 67.75 to 93.85% for MB dye removal after 180 min of light irradiation. The rate constants calculated via the pseudo-first-order kinetics mechanism are found to be 0.00532/min for LaFeO3 and 0.01476/min for LaCo0.01Fe0.99O3, respectively. In addition, the most effective LaCo0.01Fe0.99O3 catalyst has demonstrated remarkable degradation performance towards Tetracycline (TC) and Methyl Orange (MO) dye with an efficacy of 93.81% and 69.67%, respectively, indicating its versatility. Further, the pristine and doped LaFeO3 were structurally optimized using DFT, and the computed band gaps were following the experimental data. Interestingly, the same catalyst can be employed as a light-induced electrocatalyst in addition to water treatment by taking advantage of its dual functionality. The LaCo0.01Fe0.99O3 catalyst achieved a benchmark current density of 10 mA/cm2 for H2 evolution at an overpotential of 297 mV vs. RHE which further improved to 190 mV vs. RHE under illumination. This work provides valuable insights on partial Co incorporation at the B-site of LaFeO3 for the development of visible-light-induced photocatalytic and electrocatalytic systems, which is hoped to contribute to the advancement of sustainable energy production and environmental remediation. © 2024, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Correction to: Enhancing glucose detection: Vanadium-doped TiO2 (V0.07Ti0.93O2) as non-enzymatic biosensor (Journal of Materials Science: Materials in Electronics, (2024), 35, 16, (1102), 10.1007/s10854-024-12815-x)
(Springer, 2024) Rao, L.; Badekai Ramachandra, B.
In Fig. 7 of this article, the inset in Fig. 7a and the figure captionÂ should have appeared as shown below. (Figure presented.) a Cyclic voltammogram of V0.07Ti0.93O2@NF in 0.1 M KOH with the scan rate of 5â€“75 mV/s. The corresponding anodic and cathodic peak current as the function of the square root of the scan rate (Inset); b The successive addition of glucose in 0.1 M KOH at the scan rate of 50Â mV/s; c The CA study of V0.07Ti0.93O2@NF in 0.1 M KOH with the successive addition of glucose in stirring condition. Applied potential: 0.75 V; d Calibration plot of the V0.07Ti0.93O2@NF for the determination of the glucose; e DPV study of V0.07Ti0.93O2@NF in 0.1 KOH with the successive addition of glucose; f Cyclic stability of the V0.07Ti0.93O2@NF in 0.1 KOH with the presence of 2 mM glucose Â© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Electrocatalytic synergies of melt-quenched Ni-Sn-Se-Te nanoalloy for direct seawater electrolysis
(Elsevier B.V., 2024) Rodney, J.D.; Joshi, S.; Ray, S.; Rao, L.; Deepapriya, S.; Carva, K.; Badekai Ramachandra, B.R.; Udayashankar, N.K.; Perumal, S.; Sadhana, S.; Justin Raj, C.J.; Kim, B.C.
The study focuses on the development of binary nanoalloys based on metal dichalcogenides (Sn30Se70, Ni30Te70) and quaternary nanoalloy (Ni15Sn15Se35Te35) using the melt quenching technique. The nanoalloys show extensive water splitting in fresh and real seawater. Sn30Se70-coated nickel foam achieved a benchmark current density of 349 mV for the oxygen evolution reaction (OER), while Ni15Sn15Se35Te35-coated nickel foam (NF) required only 185 mV for the hydrogen evolution reaction (HER) in 1 M KOH. The study also shows that a two-electrode system can achieve sustained total water splitting at higher current densities (1 A.cm?2). Modification with a CuSx layer over NF at the OER end facilitated faster kinetics and mitigated chlorine corrosion enabling direct seawater splitting at 1.26 V. Continuous direct splitting of seawater at 100 mA cm?2 for 120 h required only 1.88 V, showing an efficiency of 92.9 % for H2 production in real seawater. © 2024 Elsevier B.V.
Electrochemical insights into manganese-cobalt doped ?-Fe2O3 nanomaterial for cholesterol detection: a comparative approach
(Royal Society of Chemistry, 2025) Sushmitha, S.; Ray, S.; Rao, L.; Nayak, M.P.; Carva, K.; Badekai Ramachandra, B.R.
Herein, a self-assembled hierarchical structure of hematite (?-Fe2O3) was synthesized via a one-pot hydrothermal method. Subsequently, the nanomaterial was doped to obtain MxFe2?xO3 (M = Mn-Co; x = 0.01, 0.05, and 0.1) at precise concentrations. An electrode was fabricated by coating the resulting nanocomposite onto a nickel foam (NF) substrate. Electrochemical characterization demonstrated the excellent performance of cobalt-doped ?-Fe2O3, among which Co0.05Fe0.95O3 (CF5) exhibited a superior performance, showing a two-fold increase in sensitivity of 1364.2 ?A mM?1 cm?2 (±0.03, n = 3) in 0.5 M KOH, a limit of detection (LOD) of ?0.17 mM, and a limit of quantification (LOQ) of ?0.58 mM. The Density Functional Theory (DFT) was performed to understand the doping prompting in the reduced bandgap. The fabricated electrode displayed a rapid response time of 2 s and demonstrated 95% stability, excellent reproducibility, and selectivity, as confirmed by tests with several interfering species. A comprehensive evaluation of the electrode's performance using human blood serum highlighted its robustness and reliability for cholesterol detection in clinical settings, making it a promising tool for clinical and pharmaceutical applications. © 2025 The Royal Society of Chemistry.
Electrodeposited CoMnS/NiCo2S4 nanocomposite for high performance supercapacitors
(Elsevier Ltd, 2024) Mascarenhas, F.J.; Rodney, J.D.; Rao, L.; Kim, B.C.; Badekai Ramachandra, B.R.
In this work, we report a facile two-step electrodeposition method to fabricate a CoMnS/NiCo2S4/NF (CMS/NCS/NF) composite on nickel foam (NF) for application of supercapacitor electrode. The electrochemical performance of this composite material has been extensively investigated, revealing superior performance compared to individual CMS/NF and NCS/NF materials. The CMS/NCS/NF composite exhibits an exceptionally high specific capacity of 707 C/g at a current density of 1 A/g in a three-electrode system. Remarkably, the material retains 92 % of its specific capacitance after 5000 cycles, indicating excellent cyclic stability and durability. To further explore its practical applications, we constructed a two-electrode symmetric supercapacitor using the CMS/NCS/NF electrode. This symmetric cell demonstrates an outstanding energy density of 97.5 Wh/kg and a peak power density of 12 kW/kg, underscoring its potential for high-performance energy storage applications. These comprehensive studies indicate that the synthesized CMS/NCS/NF is a highly promising candidate for supercapacitor electrodes, offering both high capacity and long-term stability. This work paves the way for the development of efficient and durable energy storage devices. © 2024 Elsevier Ltd
Elucidating mechanisms and DFT analysis of monometallic Vanadium incorporated nanoporous TiO2 as advanced material for enzyme-free electrochemical blood glucose biosensors with exceptional performance tailored for point-of-care applications
(Elsevier Inc., 2024) Rao, L.; Rodney, J.D.; Naik, S.; Udayakumar, U.; Udayashankar, N.K.; Kim, B.C.; Badekai Ramachandra, B.R.
Diabetes is a chronic condition that can last a lifetime and has claimed a great number of lives in recent years. This motivated scientists to design a glucose biosensor to monitor and control blood glucose levels in diabetic patients. Herein, hydrothermal derived Vanadium (V), Nickel (Ni), and Cobalt (Co)-doped TiO2 (MxTi1-xO2 (x = 0.01, 0.02, and 0.03)) was synthesized to achieve the best material to answer the pertaining problem. Of all the materials synthesized, V0.03Ti0.97O2@NF demonstrated the highest level of sensitivity, and selectivity, and has higher electrochemical cycling stability in 0.1 M KOH. It exhibits a very high sensitivity of 1129.31 μAmM-1cm-2 and Limits of Detection (LOD) and Limits of Quantification (LOQ) of 1.8 μM (S/N = 3) and 6.2 μM, respectively, with a broad linear range from 20 μM to 2 mM. The DFT approach was employed computationally to analyze the adsorption of glucose on surfaces of pure TiO2 and TiO2 doped with V, Ni, and Co respectively. The research findings highlight that when it comes to its interaction with glucose, pure TiO2 exhibits significantly less reactivity compared to transition metal-doped TiO2. Experimentally it shows that the V0.03Ti0.97O2@NF surface has the most sensitive glucose detection capability and it also exhibited significant selectivity towards glucose in the presence of additional interference. It demonstrated 100% retention after cycling stability and had a shelf life of ≃30 days. The V0.03Ti0.97O2@NF-based sensor exhibits accurate glucose sensing, even for human serum samples. © 2024 Elsevier B.V.
Enhancing glucose detection: Vanadium-doped TiO2 (V0.07Ti0.93O2) as non-enzymatic biosensor
(Springer, 2024) Rao, L.; Badekai Ramachandra, B.R.
Humans need glucose as a source of energy, but abnormal glucose levels can have a negative influence on health. Elevated blood glucose levels are a common symptom of conditions like diabetes, which can cause problems with the kidneys, nerves, and cardiovascular system. For precise glucose monitoring and control, reliable glucose biosensors are essential. In a recent study, we synthesized Vanadium-doped TiO2 (V0.07Ti0.93O2) using the solvothermal method. This material underwent thorough SEM and XRD investigations to characterize it before being coated over nickel foam (NF) to fabricate a non-enzymatic glucose biosensor. Notably, our research shows that this biosensor outperforms the Ag/AgCl electrode at 0.6 V with improved cyclic electrochemical stability and more effective glucose oxidation using the electrochemical workstation. The material has a sensitivity of 1482.8 μA.mM−1 cm−2 and has a broad linear range spanning 0.2 mM to 2 mM. The biosensor has extraordinary sensitivity, providing accurate glucose detection even at lower concentrations, with a limit of detection (LOD) at 0.488 mM and a limit of quantification (LOQ) at 1.629 mM. These results highlight the biosensor’s potential for reliable and precise glucose sensing, a crucial benefit for continuous glucose monitoring, especially for individuals with diabetes. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Growth of octahedral structured AgBiS2 single crystals and its insights on the high performance electrocatalytic hydrogen generation
(Elsevier Ltd, 2024) Jauhar, R.O.M.; Ramachandran, K.; Deepapriya, S.; Joshi, S.; Ghfar, A.A.; Rao, L.; Badekai Ramachandra, B.R.; Udayashankar, N.K.; Vadivel, V.; Raji, R.; Kim, B.C.; Rodney, J.D.
Given the enormous depletion of fossil fuels and growing environmental concerns, there is an immediate need to develop alternative and clean energy sources. Hydrogen (H2), recognized for its cleanliness and renewability, is poised to meet future energy requirements. Consequently, ongoing research is focused on the development of electro-active, durable, and cost-effective catalysts to replace expensive noble metal-based electrocatalysts. In this study, microscale AgBiS2 chalcogenide derived from a single crystal is reported as promising electrocatalysts for the Hydrogen Evolution Reaction (HER) with a remarkably low overpotential. The physico-chemical characterization of the AgBiS2 catalyst has been investigated using various analytical techniques. The synthesized AgBiS2 catalyst exhibits excellent HER activity, manifesting a low overpotential of 86 mV at a current density of 10 mA cm−2 and a Tafel slope of 44 mV dec−1, along with superior stability even after 24 h in HER at a very high current density. The developed AgBiS2 also showcased stable production when subjected to a two-electrode system. The enhanced alkaline HER activity of AgBiS2 can be attributed to its phase purity, high crystallinity, and the presence of high active sites. The observed high electrochemical performance and stability position AgBiS2 as a potential electrocatalyst for the hydrogen evolution reaction. This finding holds significant promise in the quest for efficient, durable, and economically viable catalysts to drive the shift towards clean and renewable energy sources. © 2024 Hydrogen Energy Publications LLC
Pd/C-decorated SnO2 for advanced non-enzymatic cholesterol biosensing: analytical application in clinical blood specimens
(Elsevier Inc., 2025) Rao, L.; Rodney, J.D.; S, S.; Mascarenhas, F.J.; Nayak, M.P.; Kim, B.C.; Badekai Ramachandra, B.R.
Cholesterol, a critical biomolecule, plays a vital role in physiological functions; however, elevated levels are associated with chronic conditions such as cardiovascular diseases, which remain a leading cause of mortality globally. To address this challenge, this study presents the synthesis of SnO2-Pd/C nanocomposite through a two-step process as a promising material for non-enzymatic cholesterol biosensing. Initially, SnO2 was synthesized via a hydrothermal method and subsequently decorated with Pd/C. The resulting SnO2-Pd/C nanocomposite was integrated with nickel foam (NF) as the active material for biosensor development. The biosensor demonstrated a remarkable sensitivity of 1560 µA mM?1 cm?2 for cholesterol detection, which is approximately three times higher than that of SnO2-NF (546 µA mM?1 cm?2). Key performance metrics included a Limit of Detection (LOD) of 28 µM and a Limit of Quantification (LOQ) of 34 µM in 0.1 M KOH solution, with a linear detection range extending from 200 µM to 2 mM. The SnO2-Pd/C-NF biosensor exhibited outstanding cyclic stability, retaining 97 % of its performance over 30 days, underscoring its potential for reliable and long-term applications. Furthermore, the sensor demonstrated robust and consistent sensing performance with human serum samples under standard conditions, highlighting its practical applicability in clinical diagnostics. © 2025 Elsevier B.V.
Recycling waste plastics and biowaste into high-performance NiCo-MOF/activated carbon electrocatalyst for overall water splitting
(Elsevier Ltd, 2025) Nayak, M.P.; Rao, L.; Rodney, J.D.; S, S.; Rohit, A.G.; Badekai Ramachandra, B.R.
Environmental and energy crises are the most significant global challenges. Developing non-precious and environmentally sustainable electrocatalysts remains critical for advancing renewable hydrogen production. This study presents a novel hybrid electrocatalyst comprising a NiCo-BDC Metal-Organic Framework (NiCo-MOF), where the BDC (Benzene 1,4-di carboxylic acid) ligand was obtained by recycling waste poly(ethylene terephthalate) (PET) bottles, integrated with activated carbon (AC) derived from dried drumstick (Moringa olifera) biowaste, via a one-pot hydrothermal method. The research emphasizes optimizing the AC content within the MOF matrix to enhance catalytic performance. The synergistic interaction between NiCo-MOF and AC significantly reduces the overpotentials required for the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) in an alkaline medium. Notably, the optimized composite, NiCo-MOF@40AC, exhibited enhanced crystallinity, BET surface area, and electrocatalytic activity. At a current density of 100 mA cm?2, NiCo-MOF@40AC achieved overpotentials as low as 217 mV for HER with a Tafel slope of 105.6 mV dec?1 and 315 mV for OER with a Tafel slope of 42.2 mV dec?1. Furthermore, this material demonstrated robust stability over a 24 h chrono potentiometric test, maintaining performance at an elevated current density of 200 mA cm?2. In a two-electrode system, NiCo-MOF@40AC needed only 1.58 V to sustain a current density of 10 mA cm?2, exhibiting stability over 48 h and 24 h at a current density of 10 mA cm?2 and 400 mA cm?2, respectively. An average faradaic efficiency was found to be 93.48 % for HER and 91.91 % for OER. These findings highlight the potential of NiCo-MOF@40AC as an efficient electrocatalyst, characterized by a high surface area, rapid electron transfer, favorable structural properties, and enhanced reaction kinetics. © 2025 Hydrogen Energy Publications LLC
Sustained hydrogen production through alkaline water electrolysis using Bridgman–Stockbarger derived indium-impregnated copper chromium selenospinel
(Elsevier Ltd, 2024) Jauhar, R.M.; Raji, R.; Deepapriya, S.; Raja, A.; Rao, L.; Joshi, S.; Era, P.; Badekai Ramachandra, B.R.; Udayashankar, N.K.; Vadivel, V.; Mangalaraja, R.V.; J, J.; Ghfar, A.A.; Senthilpandian, M.; Kim, B.C.; Rodney, J.D.
The depletion of conventional fossil fuels necessitates the development of sustainable energy alternatives, with electrochemical water splitting for hydrogen (H2) production being a promising solution. However, large-scale hydrogen generation is hindered by the scarcity of cost-effective electrocatalysts to replace noble metals such as Pt and RuO2 in the Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER). In this study, we report the synthesis of CuCr2-xInxSe4 (x = 0, 0.2, 0.4) using a dual approach combining the Bridgman-Stockbarger method and ball milling. Among the synthesized materials, CuCr1.8In0.2Se4 demonstrates outstanding HER activity in 1.0 M KOH, achieving a potential of ?0.16 V vs. RHE at a current density of 10 mA cm?2. Moreover, the material shows remarkable durability during a three-electrode accelerated degradation test in an alkaline medium, maintaining its performance over 24 h at a constant current density of ?200 mA cm?2, with a stable potential of ?0.57 V vs. RHE. Additionally, CuCr1.8In0.2Se4 was tested in a two-electrode configuration alongside CoFe LDH, achieving a benchmark of 1.7 V for overall water splitting. It sustained a current density of 400 mA cm?2 for 24 h in an accelerated degradation test, exhibiting a minimal loss of 0.1 V after the testing period. These results highlight CuCr1.8In0.2Se4 as a promising non-noble metal catalyst for HER, demonstrating its potential to reduce reliance on noble materials for large-scale hydrogen production. © 2024 Hydrogen Energy Publications LLC