Synergistic effects in Mn2O3/CuO nanocomposites for enhanced and color-tunable emission for optoelectronic applications Vangapandu Anusha, Akumarti Raju, Budithi Ravi Kumar, Gattupalli Manikya Rao, K. Samatha, Naresh Kumar Rotte, Kasinathan Kaviyarasu Applied Physics A Materials Science and Processing, 2026 This work demonstrates the simple, economical, and rapid synthesis of magnesia oxide (Mn 2 O 3 ), copper oxide (CuO), and their compound Mn 2 O 3 /CuO composite, employing fundamental green practices. The as-synthesized Mn 2 O 3 , CuO, and Mn 2 O 3 /CuO have been evaluated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). The presence of distinct Mn 2 O 3 and CuO phases, as well as the interphase between them, is evident in the TEM micrographs. Using the Tauc plot from absorption spectra, the energy bandgaps of pure Mn 2 O 3 , CuO, and the Mn 2 O 3 /CuO composite were estimated to be 2.6, 2.1, and 3.2 eV, respectively. The obtained materials were investigated for their photoluminescence (PL) and chromaticity characteristics to understand interfacial charge-transfer behavior. The PL spectra reveal broad blue - green emissions with main peaks located at 414 –437 nm for Mn 2 O 3 , 414 –439 nm for CuO, and a slightly red-shifted, intensified band at 435 nm for the Mn 2 O 3 /CuO composite. The corresponding CIE 1931 chromaticity coordinates (x ≈ 0.31, y ≈ 0.58) confirm a vivid green emission region, indicating improved color purity and radiative efficiency. These results demonstrate that coupling Mn 2 O 3 with CuO tailors the electronic band alignment, suppresses non-radiative losses, and promotes strong visible luminescence, making the Mn 2 O 3 /CuO nanocomposite a promising candidate for green light - emitting and optoelectronic devices.
Developing energy storage applications for next generation Hari Babu Pengonda, Naresh Kumar Rotte, Sampath Kumar Puttapati, Subbareddy Yerramala New Technologies for Energy Transition Based on Sustainable Development Goals Factors Contributing to Global Warming, 2024
Biomass-derived sustainable mesoporous activated carbon as an efficient and recyclable adsorbent for the adsorption of hazardous dyes Y. Subba Reddy, Naresh Kumar Rotte, B.K. Sudhakar, N. Ramakrishna Chand, Ramavath Janraj Naik, Sudip Mandal, M. Ravi Chandra Hybrid Advances, 2024 The use of activated carbon obtained from biomass in wastewater treatment has grown in popularity due to its sustainability and low manufacturing cost. Mesoporous activated carbon (MAC), with a large surface area (480 m2/g) and remarkable adsorption capacity, was produced at 550 °C using affordable Ficus religiosa leaf as a biomass precursor. The developed MAC was used to adsorb the hazardous contaminants of acid blue 9 (AB9) and malachite green (MG) from wastewater. To characterize MAC, various analytical techniques were used, including XRD, Raman, HR-SEM, HR-TEM, EDAX, FTIR, BET surface area analysis, TGA, and the associated DTA. The observed data confirms the production of the graphitic framework in the synthesized MAC but also demonstrates the dispersion of mesopores with a diameter of 4 nm. Also, BET, HR-SEM, and HR-TEM images confirmed the presence of high pore density and dye adsorption surface area. MAC dye adsorption capacity with optimum adsorbent dosage of 0.2g and 0.3g was estimated as 1.552×10-4 (mol/g) (123.04 mg/g) and 1.495×10-4 (mol/g) (138.58 mg/g) for AB9 and MG respectively at equilibrium of 120 min. The regression coefficients derived from the Freundlich, Langmuir, and D-R adsorption isotherms peak are compared, and the R2 value of 0.99 reported by Langmuir suggests that the adsorption of AB9 and MG adheres to the Langmuir adsorption isotherm by best fitting the equilibrium, recommending monolayer coverage. The chemisorption mechanism is defined by the combination of adsorption kinetics and a pseudo-second-order model. Besides, the sustainability was shown for five adsorptions–desorption cycles judge the utility and economic viability of the adsorption process. The plausible adsorption mechanism of MAC over AB9 and MG is mediated by synergetic interactions such as π-π interactions, hydrogen bonding, and electrostatic interactions. Therefore, exceptional stability, sustainability, and reliability for up to five adsorption run cycles of MAC justify its superiority over other adsorbents in the adsorption of AB9 and MG from wastewater.
Facile synthesis and defect optimization of 2D-layered MoS2 on TiO2 heterostructure for industrial effluent, wastewater treatments Ramalingam Gopal, Maria Magdalane Chinnapan, Arjun Kumar Bojarajan, Naresh Kumar Rotte, Joice Sophia Ponraj, Ravi Ganesan, Ivanov Atanas, Manivannan Nadarajah, Rajesh Kumar Manavalan, Joao Gaspar Scientific Reports, 2020 Current research is paying much attention to heterojunction nanostructures. Owing to its versatile characteristics such as stimulating morphology, affluent surface-oxygen-vacancies and chemical compositions for enhanced generation of reactive oxygen species. Herein, we report the hydrothermally synthesized TiO2@MoS2 heterojunction nanostructure for the effective production of photoinduced charge carriers to enhance the photocatalytic capability. XRD analysis illustrated the crystalline size of CTAB capped TiO2, MoS2@TiO2 and L-Cysteine capped MoS2@TiO2 as 12.6, 11.7 and 10.2 nm, respectively. The bandgap of the samples analyzed by UV–Visible spectroscopy are 3.57, 3.66 and 3.94 eV. PL spectra of anatase phase titania shows the peaks present at and above 400 nm are ascribed to the defects in the crystalline structure in the form of oxygen vacancies. HRTEM reveals the existence of hexagonal layered MoS2 formation on the spherical shaped TiO2 nanoparticles at the interface. X-ray photoelectron spectroscopy recommends the chemical interactions between MoS2 and TiO2, specifically, oxygen vacancies. In addition, the electrochemical impedance spectroscopy studies observed that L-MT sample performed low charge transfer resistance (336.7 Ω cm2) that promotes the migration of electrons and interfacial charge separation. The photocatalytic performance is evaluated by quantifying the rate of Congo red dye degradation under visible light irradiation, and the decomposition efficiency was found to be 97%. The electron trapping recombination and plausible photocatalytic mechanism are also explored, and the reported work could be an excellent complement for industrial wastewater treatment.
2018-2019 Visiting Scientist 2018-2019
Nanospan India Pvt Ltd, Hyderabad, India
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