|
Ashfaq, M., Talreja, N., Chauhan, D., Rodriguez, C. A., Mera, A. C., & Mangalaraja, R. V. (2022). Synthesis of reduced graphene oxide incorporated bimetallic (Cu/Bi) nanorods based photocatalyst materials for the degradation of gallic acid and bacteria. J. Ind. Eng. Chem., 110, 447–455.
Abstract: Gallic acid (GA) is a polyphenols compound commonly present in wastewater that immensely affects aquatic and human life. GA is also responsible for the inhibitory effects on the microbial activity in the soil, thereby decreasing the fertility of the soil. Therefore, the removal of GA from the wastewater is necessary to combat such issues. The present study focused on the synthesis of reduced graphene oxide (rGO) incorporated bimetallic (Cu/Bi) based nanorods (r-GO-Cu/Bi-NRs) and their photocatalytic applications. Incorporating GO within the CuBi2O4-NRs might decrease the bandgap value, thereby increasing the interfacial charge transfer. Moreover, GO increased the reactive sites and oxygen defects onto the r-GO-Cu/Bi-NRs that led to the separation rate of the photo-induced charge carriers and migration, thereby enhancing the photodegradation ability of the synthesized r-GO-Cu/Bi-NRs. The synthesis process of the r-GO-Cu/Bi-NRs is facile, novel, and economically viable for the photocatalytic degradation of organic pollutants.
|
|
|
Baraneedharan, P., Shankari, D., Arulraj, A., Sephra, P. J., Mangalaraja, R. V., & Khalid, M. (2023). Nanoengineering of MXene-Based Field-Effect Transistor Gas Sensors: Advancements in Next-Generation Electronic Devices. J. Electrochem. Soc., 180(10), 107501.
Abstract: In recent years, Two-Dimensional (2D) materials have gained significant attention for their distinctive physical and chemical properties, positioning them as promising contenders for the next generation of electronic technologies. One notable group within these materials is MXenes, which have exhibited remarkable breakthroughs across various technological domains, including catalysis, renewable energy, electronics, sensors, fuel cells, and supercapacitors. By making subtle modifications to the surface termination, introducing metal ions, precise etching timing, and applying surface functionalization, the characteristics of MXenes can be fine-tuned to achieve desired band structures, rendering them suitable for sensor design. This review focuses on the strategic development of gas sensors based on Field-Effect Transistors (FETs), thoroughly examining the latest progress in MXene-based material design and addressing associated challenges and future prospects. The review aims to provide a comprehensive overview of MXene, summarizing its current applications and advancements in FET-based gas sensing.
|
|
|
Kumar, N., Gajraj, V., Rameshbabu, R., Mangalaraja, R. V., Joshi, N. C., & Priyadarshi, N. (2022). Redox additive electrolyte assisted promising pseudocapacitance from strictly 1D and 2D blended structures of MnO2/rGO. Mater. Charact., 189, 111991.
Abstract: A promising sustainable energy storage characteristic is achieved in redox additive electrolyte by developing strict blend of one dimensional (1D) and two dimensional (2D) structures. Hydrothermal reaction is followed to obtain the desired morphology. Two dimensional (2D) reduced graphene oxide (rGO) is added into the redox reaction between potassium permanganate and sodium nitrite to obtain nanocomposite comprising 1D and 2D blended structures of MnO2/rGO. Their structures and morphologies are studied by XRD, Raman and HRTEM analyses, respectively. The pseudocapacitive behaviour is studied in a redox additive electrolyte comprising KOH and K3Fe(CN)(6). The effect of electrolytic concentration was studied by varying the concentration of K3Fe(CN)6. The specific capacity is considerably enhanced up to 1741 F/g, 8.75 A/g with increase in concentration of K3Fe (CN)6. The role of redox couple [Fe(CN)(6)](3)-/[Fe(CN)(6)](4)-played a key role in adding the charge movement across the electrode which tuned well with the manganese ions to obtain one of the most promising pseudo-capacitances from the developed 1D and 2D blended structures of MnO2/rGO. For in-depth analysis of Fe ions movement, a symmetric supercapacitor cell is constructed to achieve a commendable specific capacitance of 216 F/g at 3.75 A/g. Prolong cycling hinted decreasing electrolytic interfacial layers resulting in fast reversible ki-netics of Fe(III) -> Fe(II) ions to achieve astonishing capacity retention of 127% after 3000 cycles.
|
|
|
Pandiyarajan, T., Mangalaraja, R. V., Karthikeyan, B., Arulraj, A., & Gracia-Pinilla, M. A. (2023). Fabrication and spectroscopic investigation of sandwich-like ZnO:rGO:ZnO: rGO:ZnO structure by layer-by-layer approach. Inorg. Chem. Commun., 149, 110383.
Abstract: Transparent conducting materials (TCMs) are the heart of modern optoelectronic industries and the properties of TCMs could be improved by the introduction of 2D carbon materials. In this report, the influence of order layering on microstructural, transparency and emission characteristics of ZnO:rGO:ZnO:rGO:ZnO and rGO:ZnO: rGO:ZnO:rGO sandwich structures has been investigated. The layer-by-layer approach has been adopted for the fabrication of sandwich structured materials ZnO:rGO:ZnO:rGO:ZnO and rGO:ZnO:rGO:ZnO:rGO through the spin coating technique. The sandwich structures of ZnO and rGO exhibited hexagonal wurtzite structure of ZnO without any impurities were identified through XRD. The ordering of layer's influenced the microstructural parameters and were significantly altered. The spherical nature of the particles and the formation of the sand-wich structures were confirmed by using SEM micrograph. The reduction in an optical transparency and nar-rowing bandgap of the ZnO upon the order of layering were identified through transmission spectra. The lower energy shift of near band edge (NBE) emission and reduction in the emission intensity with respect to pure ZnO nanostructures was observed. The present work provides a simple layer-by-layer approach to fabricating sand-wich structures and improving the optical properties which have potential applications in various optoelectronic devices.
|
|
|
Pugazhenthiran, N., Valdes, H., Mangalaraja, R. V., Sathishkumar, P., & Murugesan, S. (2022). Graphene modified “black {001}TiO2” nanosheets for photocatalytic oxidation of ethylene: The implications of chemical surface characteristics in the reaction mechanism. Sep. Purif. Technol., 292, 121008.
Abstract: In this work, crystal facets, bandgap, size and shape of reduced graphene oxide (rGO) modified anatase {001} black TiO2 nanosheets (rGO-B-TiO2 NSTs) were tailored for the photocatalytic oxidation of ethylene under high humidity content. XRD, Raman and HR-TEM analyses confirm that rGO-B-TiO2 NSTs have a 94 % of exposed {001} facets with high number of oxygen vacancies. In addition, rGO-B-TiO2 NSTs exhibit increased values of surface area and porosity compared to its pristine form. A 48 and 34 mu mol g(-1) of ethylene are adsorbed at the surface of rGO-B-TiO2 NSTs in the absence and in the presence of humidity, respectively. In addition, operando DRIFTS analyses provide the insight of surface interactions between ethylene molecules and adsorption sites of rGO-B-TiO2 NSTs. The photocatalytic removal efficiencies of the synthesized materials under both UV and visible light irradiation proceed as follows: rGO-B-TiO2 NSTs > B-TiO2 NSTs > TiO2 NSTs > commercial TiO2 NPs. Further, ethylene is very quickly photocatalytic oxidized when rGO-B-TiO2 NSTs is applied under UV light irradiation, having a 72 and 92 % ethylene removal in the absence and in the presence of humidity, respectively. Moreover, a 48 and 58 % of ethylene removal takes place in the absence and presence of humidity under visible light irradiation, respectively. Results indicate that rGO-B-TiO2 NSTs boost the photocatalytic activity through their virtue of visible-light absorption properties (Bandgap = 2.61 eV) and the rapid electron-hole separation at the rGO {0 0 1} black TiO2 NSTs interfaces. Such findings are confirmed through UV-visible diffused reflectance, photoelectrochemical and photoluminescence analyses. Nanosheets made of rGO modified {0 0 1} black TiO2 could be used as an effective photocatalyst for the removal of ethylene from large volume fruit storage areas by exploiting a simple light source in the presence of high content of humidity.
|
|
|
Rao, B. V. B., Jena, M., Aepuru, R., Udayabhaskar, R., Mangalaraja, R. V., Espinoza-Gonzalez, R., et al. (2022). Superior electromagnetic wave absorption performance of Fe3O4 modified graphene assembled porous carbon (mGAPC) based hybrid foam. Mater. Chem. Phys., 290, 126512.
Abstract: High performance Fe3O4 modified graphene assembled porous carbon (mGAPC) based epoxy paint coated on Polyethylene (PE) foam is realized by spray technique to fabricate light weight electromagnetic absorbers. The mGAPC as a pigment in a standard composition of commercial paint was optimized and the influence of solvent and additives are studied to achieve X-band (8.2-12.4 GHz) electromagnetic wave absorption (EA) in the hybrid foam (HF). From the comparative studies, the hybrid foams obtained from epoxy paint with toluene as solvent (without Mn-octate as additive) showed a Reflection Loss (RL) -19 dB (in the range of 8.3-8.7 GHz), which was further increased with the coating cycles up to -43 dB (in 10.2-11.2 GHz).The observed rise is attributed to increase in localized interfacial polarization that arises at the combined interfaces of mGAPC. The result showed 99% loss, which projects a promising EA paint for practical applications. Further thickness dependent studies of EA in Paint Coat HF1, reveals that with increasing thickness from 0.3 to 2 mm, the RL also increases from -19 to -43 dB with changing absorption band. The superior EA properties are correlated to the percolation threshold, pigment dispersibility and further correlated to the strong absorption, destructive interference, multiple internal reflections and interfacial polarization of the radiation in the hybrid foam. Moreover, considering the paint lowest thickness similar to 0.3 mm with -19 dB of RL, the hybrid foam promises a cost-effective, fine, light-weight EA/ RL material for secure electronic devices and packaging in civil and defence applications.
|
|
|
Shanmugaraj, K., Vinoth, V., Pugazhenthiran, N., Valdes, H., Salvo, C., Sepulveda, E., et al. (2023). Ferrihydrite- Graphene oxide foams as an efficient adsorbent for Arsenic (III) removal from an aqueous solution. Inorg. Chem. Commun., 153, 110892.
Abstract: We report the synthesis of a new range of ferrihydrite-graphene oxide (FH-GO) foams using chitosan as cross linker, with varying iron content (5 wt%, 10 wt%, and 20 wt% of FH) as highly efficient adsorbents for the removal of arsenic (III) (As(III)) in an aqueous solution. The sonochemical methods were adopted to synthesize various FH-GO foams and were further characterized by XRD, SEM, TEM, FTIR, Raman, and XPS techniques. The synthesized materials were used for the removal of As(III) in both batch and fixed bed absorbent column methods. The adsorption isotherm results showed that the 10 wt% of FH-GO foams demonstrated a superior adsorbent for the As(III) with high adsorption capacities than that of the other two FH-GO foams (5 wt% and 20 wt% of FH). Moreover, 10 wt% of FH-GO foams was also demonstrated to be nearly a complete (>98.4%) removal of As(III) ions at neutral pH 7. The adsorption isotherm fitted very well with the Langmuir model with the highest accuracy data for all the synthesized adsorbent materials. In addition, the fixed bed absorbent column method was also adopted for the removal of As(III) ions in the water sample, which showed > 99.2% of removal efficiency. The outstanding adsorption capabilities, along with their easy and low-cost synthesis, make these kinds of adsorbents extremely capable for commercial applications in wastewater treatment and drinking water purification.
|
|
|
Vinoth, V., Kaimal, R., Selvamani, M., Michael, R., Pugazhenthiran, N., Mangalaraja, R. V., et al. (2023). Synergistic impact of nanoarchitectured GQDs-AgNCs(APTS) modified glassy carbon electrode in the electrochemical detection of guanine and adenine. J. Electroanal. Chem., 934, 117302.
Abstract: In this work, a facile green approach for the synthesis of graphene quantum dots (GQDs) embedded on silicate network silver nanocrystals (GQDs-AgNCs(APTS)) is reported. Moreover, glassy carbon-GC electrodes were mod-ified with the prepared nanocomposite containing graphene quantum dots supported on silver nanocrystals (GQDs-AgNCs(APTS)) and applied for simultaneous detection of guanine (GA) and adenine (AD). The chemically modified electrode was assessed during the determination of purine bases by cyclic voltammetry-CV and dif-ferential pulse voltammetry-DPV. The incorporation of GQDs-AgNCs(APTS) nanocomposites over the surface of the GC electrode considerably enhances the anodic peak currents and decreases the adenine and guanine peak potentials. Compared to other electrodes, GQDs-AgNCs(APTS)/GC improved the electrochemical behavior towards the detection of adenine and guanine. At optimal conditions, calibration curves were obtained by DPV being linear in the range of 0.1-6.0 mu M and 0.1-5.0 mu M for guanine and adenine, respectively. The detec-tion limits of both guanine and adenine were estimated as 0.1 mu M. Additionally, interferences analyses were performed on the existence of other interferent compounds. Furthermore, the method developed for the iden-tification of GA and AD was proved using fish sperm DNA samples.
|
|