The University of Kota (UOK) is a public university in Kota, Rajasthan, India. It was established through the University of Kota Act 2003, enacted by the Rajasthan State Legislature and assented by the Governor of Rajasthan. Prof. B. L. Verma was appointed as the first Vice Chancellor of the University and Sh. N.C. Jain, The Governor of Rajasthan was the first chancellor of the University. The University is recognized by the UGC under 2(f) in year 2003 and under 12(b) in year 2012. It offers undergraduate and postgraduate courses along with research. Shri Kalraj Mishra the Governor of Rajasthan, is the chancellor and Prof. Neelima Singh is the Vice Chancellor of the university.The University of Kota has 175 affiliated colleges and autonomous departments across the six districts of the Rajasthan state, Kota, Jhalawar, Bundi, Baran, Karauli and Sawai Madhopur are under the territorial jurisdiction of the university. The university has six faculties - Arts, Science, Social Sciences, Commerce and Management, Law and Education..
Laser-induced graphene (LIG) has garnered substantial consideration in applications based on energy storage owing to its economical nature and exceptional performance as a flexible electrode material. This work presents a straightforward method for synthesising phosphorus-doped laser-induced graphene (PLIG). The synthesis comprised the formation of pure LIG, subsequent dispersion of phosphoric acid via the drop-casting technique, and re-irradiation. The multilayer structure of PLIG was confirmed via the ratio of intensities of 2D and G bands in the Raman spectrum (I2D/IG = 0.8). The presence of a peak at 2 theta similar to 26.07 degrees in X-ray diffraction spectra confirms the formation of graphene. The morphological analysis was done through field emission scanning electron microscopy and high-resolution transmission electron microscopy. The occurrence of P-O and P-C in the P 2p peak's core level spectra in X-ray photoelectron spectroscopy confirms the existence of phosphorus in LIG. Furthermore, the fabricated electrode of PLIG-2 unveiled a remarkable specific capacitance (Cs) of 105 mF cm-2 at a 2 mV s-1 scan rate, employing a three-electrode system. Moreover, the symmetric supercapacitor device (Swagelok cell) obtained a Cs of 18.6 mF cm-2 at 0.011 mA cm-2 current density, and the pouch cell offers 21 mF cm-2Cs at 0.05 mA cm-2 current density, demonstrating its application as an energy storage device.
Nitrogen-doped laser-induced graphene (NLIG) electrodes were produced via a straightforward and economical two-step laser method, utilizing polyimide (PI) as the substrate and carbon precursor, with urea as the nitrogen source. This approach involved urea dispersion followed by CO2 laser irradiation on laser-induced graphene (LIG). Raman spectroscopy revealed D, G, and 2D bands with an intensity ratio I-2D/I-G of similar to 0.8, confirming the formation of multilayer graphene. X-ray diffraction (XRD) confirmed the prominent peak interplanar spacing of 3.4 & Aring;. Furthermore, XPS confirmed the existence of pyridinic, pyrrolic, and graphitic nitrogen in the NLIG electrode. Moreover, the electrochemical performance of the NLIG electrode with urea dispersion of 1.0 mgcm(-)(2) demonstrated a remarkable areal capacitance (C-s) similar to 68 mF cm(-2) at a current density (I-d) of 0.3 mA cm(-2) in a 3-electrode configuration. The symmetric supercapacitor (SSC) device showcased remarkable energy storage capabilities, achieving C-s of 16.93 mF cm(-2) at 0.017 mA cm(-2) I-d and energy density (E-d) of 2.3 mu Whcm(-2) at power density (P-d) of 17 mu W cm(-2). Also, a pouch-type SC demonstrating its potential use in energy storage applications. The key novelty of this work lies in the formation of a laser-assisted nitrogen-doped LIG method, which removes the need for additional doping processes while improving electrochemical performance, offering a scalable and sustainable approach for high-performance supercapacitor production.
The present study aims to evaluate the influence of different separators on the electrochemical performance of a 2D g-C3N4 decorated Co3O4 symmetric supercapacitor. Exfoliated graphitic carbon nitride (ECN) was combined with Co3O4 to create nanocomposites in weight ratios of 1:0.01, 1:0.05, and 1:0.1 (COCN1, COCN2, COCN3). XRD analysis revealed that the ECN possesses a hexagonal structure, while Co3O4 exhibits a cubic spinel structure. COCN nanocomposites have been successfully synthesized, as confirmed by analyses using XRD and FTIR techniques. HR-TEM and SAED indicated that the CO3O4 adhered to the g-C3N4 matrix. The BET analysis revealed that the ECN and COCN2 show specific surface areas of 25 m2/g and 35 m2/g, respectively. The COCN2 nanocomposites attain a specific capacitance of 667.8 F/g at 1 A/g in 1.0 M KOH electrolyte, which is eight times more than ECN, due to the combined effects of the nitrogen content and cobalt oxidation states. The COCN2 exhibits an energy density of 45.45 Wh/kg at 218.75 W/kg power density, with 99.5 % capacitive retention. To explore the influence of different separators in symmetric devices, COCN2 was employed within the Swagelok assembly, featuring two separate types of separators: Whatman paper (COCN2/W/COCN2) and PVA-KOH gel electrolyte (COCN2/GE/COCN2). The COCN2/W/COCN2 device achieved a specific capacitance of 197.25 F/g at a current density of 1.0 A/g. Furthermore, it attained an energy density of 140.27 Wh/kg at a power density of 1600 W/kg, while retaining 94.23 % of its initial capacitance. In contrast, the COCN2/GE/COCN2 device showed a specific capacitance of 69.25 F/g and an energy density of 24.62 Wh/kg at 1600 W/kg, maintaining 95.4 % of its capacitance after 1000 cycles. The synergistic combination of Co3O4 and g-C3N4 offers a promising strategy for enhancing energy.
The nanocomposites of g-C3N4 were prepared with reduced graphene oxide by reducing it with ascorbic acid (AA) and NaBH4. As-fabricated g-C3N4@r-GO nanocomposites were used in a water splitting to generate hydrogen i.e. 339.82 µmolh− 1g− 1 form the nanocomposite g-C3N4@r-GO (AA) with 2.52% apparent quantum efficiency at 420 nm, which is 5.6, 3.4, 1.6, and 1.4 times higher than their counterparts, g-C3N4, GO, g-C3N4@GO, and g-C3N4@GO(NaBH4), respectively. The composites were also tested for specific capacitance, where the composite g-C3N4@r-GO (AA) demonstrated the highest specific capacitance of 322.77 F g− 1 at 2 A/g in aqueous 2 M KOH with 78.56% charge retention after 5000 cycles at 3 A/g. The SPV study confirm the formation of effective interface with p-n junction, minimum band gap by using optical absorption, effective charge transfer using EIS, interfacial interaction, layered structure, and PLE study approve minimum charge-recombination rate in nanocomposites g-C3N4@r-GO(AA) that significantly supported the reasonable H2 generation rate as well as the good super capacitive behaviour. The substance under study guarantees a promising position in the development of the mystical material for the preparation of H2 and next-generation high-performance electrochemical supercapacitors.
The study describes the fabrication and thorough analysis of hybrid PCG (PVA/CS/GO) and PCPtG (PVA/CS/PtGO) nanocomposites produced using a simple solution-mixing method. Introducing graphene oxide (GO) and platinum-decorated graphene oxide (PtG) at concentrations ranging from 1 to 5 wt% into the PVA/CS matrix allows a detailed examination of how these fillers influence the structural and optical properties of the material. Further, the study uniquely correlates the nanofiller composition with micro-structural parameters-such as crystallite size, micro-strain, dislocation density, energy density, and Young's modulus-demonstrating a tuneable structure-property relationship. Optical analyses revealed a controlled reduction in the energy band gap, accompanied by an increase in Urbach energy, refractive index, optical dielectric constant, and optical conductivity, attributed to enhanced defect density and structural disorder with higher nanofiller loading. The optical dielectric behavior, evaluated as a function of frequency and filler content, showed that the PCPtG composites deliver a markedly stronger dielectric response than the PCG samples. This highlights the role of Platinum (Pt) in enhancing the interfacial polarization and facilitating more effective charge transport within the material. The Wemple-DiDomenico single-oscillator model and Spitzer-Fan relation were employed to extract refractive dispersion parameters, validating the observed optical transitions. Notably, the ratio of free charge carriers to effective mass (N/m*) exhibited a remarkable enhancement with PtG incorporation, suggesting improved charge carrier dynamics within the composite network. Field Emission Scanning Electron Microscopy along with EDAX analysis revealed well-distributed nanofillers and robust interfacial bonding within the polymer network. The Raman and FTIR spectra have also been studied examining the behaviours of molecules and presence functional groups. The novelty of this study lies in establishing a direct correlation between nanofiller functionality (GO vs. PtG) and the resulting optoelectronic performance of PVA/CS-based nanocomposites. Their improved structural stability and adjustable optical responses make these hybrid materials strong contenders for next-generation optoelectronic technologies.
