Pachaiyappa's College is one of the oldest educational institutions in Chennai, in the South Indian state of Tamil Nadu. In addition, it is the first sole Indian college in Madras Presidency.
The development of high-performance and sustainable photocatalysts is pivotal for mitigating environmental pollution, particularly in the treatment of dye-contaminated industrial wastewater. In this study, we report the synthesis of a graphitic carbon nitride/cadmium sulfide (g-CN/CdS) composite via a facile hydrothermal method, aimed at enhancing visible-light-driven photocatalytic efficiency and long-term stability. Comprehensive structural and chemical characterizations, including X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy, confirm the successful anchoring of CdS nanoparticles onto the g-CN matrix. Photocatalytic performance evaluations reveal that the g-CN/CdS composite exhibits a significantly higher degradation rate of Congo Red (CR) dye compared to its individual counterparts, achieving an exceptional degradation efficiency of 99.85 % under visible-light irradiation. The superior activity is primarily attributed to the synergistic coupling between g-CN and CdS, which facilitates efficient charge carrier separation, suppresses electron-hole recombination, and mitigates photocorrosion. This work underscores the importance of heterojunction engineering in optimizing photocatalytic materials and offers a viable pathway for designing next-generation nanocomposites for eco-friendly and scalable wastewater remediation technologies.
The nonlinear optical (NLO) material Sarcosine 4-nitrophenol (SRNP) is anticipated to exhibit several advantageous properties, including significant NLO susceptibility, broad optical transparency, favourable crystal growth conditions, and ease of device fabrication. Nonlinear optical single crystal sarcosine 4-nitrophenol was grown by slow evaporation method. The molecular structure of the grown crystal was confirmed through single crystal X-ray diffraction, revealing a triclinic system with space group P1, Z = 2. Vibrational modes and functional groups were studied by FTIR and FT-Raman analysis. The optical transparency and band gap were examined through UV-Vis-NIR spectrum. Various quantum chemical calculations were performed on an isolated molecular unit, optimized in the gas phase using the B3LYP/6-311++G (d,p) level of theory. HOMO-LUMO, molecular electrostatic potential (MEP) and UV--Vis behaviour of the molecules are analyzed by the DFT method. The optimized molecular structure facilitated the analysis of FTIR vibrational frequencies and UV-Vis spectra provided insights into the maximum absorption wavelength, enabling the examination of different molecular phases. The fluorescence emission spectrum of the crystal was recorded within the wavelength range of 400-900 nm. Third order nonlinear optical performance of the crystal was studied by Z-scan technique and further confirmed by computational method. Additionally, FMO and MEP analysis highlighted chemically reactive regions and electrostatic potential sites are expressed in colour codes.
In this study, a new and simple electrochemical biosensor was created by modifying a glassy carbon electrode (GCE) altered with graphitic carbon nitride (g-CN) decorated with cadmium sulfide (CdS) and zirconium dioxide (ZrO2) has been was developed and used for the voltammetric assessment of theophylline (TPE), thymine (TMN). Cyclic Voltammetry (CV) was utilized to examine the properties of the modified electrode, while Differential Pulse Voltammetry (DPV) was employed to inspect the electrochemical biosensor response of TPE and TMN on the CdS/ZrO2@g-CN. The outcomes revealed that the TPE and TMN determination may be performed at the potential window while avoiding interference from the oxidation current peak. During optimal circumstances, the manufacturing nanocomposite sensor demonstrated outstanding results in determining TPE and TMN, exhibiting a linear dynamic ranging from 5 to 390 mu M, 7 to 325.5 mu M, as well as lower detection limits (S/N = 3) of 0.055and 0.064 mu M, respectively. CdS/ZrO2@g-CN/GCE sensor offered several advantages, including ease of manufacture, high sensitivity, stability, and reproducibility. The CdS/ZrO2@g-CN/GCE enables real-time sensing of Theophylline and Thymine, with recovery results verified by HPLC standards to ensure precise and accurate quantification.
This investigation explores the influence of substrate temperature on the inherent characteristics of Cu2CoSnS4 (CCTS) thin films, which consist of earth-abundant and non-toxic elements. In addition, it examines the optoelectronic application of the prepared thin films. We varied the substrate temperature from 275 degrees C to 375 degrees C in increments of 25 degrees C. We studied the crystalline structure and phases present in the CCTS thin films using X-ray diffraction and Raman spectroscopy techniques. We also used scanning electron microscopy, energy dispersive spectroscopy and UV-Vis-NIR spectrophotometry to analyze surface morphology, elemental composition, and optical properties, respectively. X-ray diffraction and Raman analysis confirm the formation of CCTS at all substrate temperatures, with the highest intensity occurring at 350 degrees C and no secondary phases present. The sample prepared at 350 degrees C exhibited the highest absorption and the lowest optical band gap (1.69 eV). This sample also achieved the highest photocurrent (42 mu A), along with a responsivity of 0.812 A/W, a detectivity of 5.43 x 1010 Jones, and an EQE of 189 %. These results demonstrate a promising approach for fabricating highperformance photodetectors with tunable properties across a broad spectrum.
A highly sensitive electrochemical sensor was developed using a graphene-supported copper sulfide/zirconium oxide nanocomposite (Graphene@CuS/ZrO)-modified glassy carbon electrode (GCE) for the simultaneous and individual detection of theophylline (TPN) and cytosine (CTN). The nanocomposite was synthesized at room temperature via a simple stirring and ultrasonication process, where graphene provided excellent electrical conductivity and CuS/ZrO nanoparticles offered abundant electrocatalytic sites. The electrochemical responses of TPN and CTN were thoroughly examined using cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), chronoamperometry, and amperometry. The Graphene@CuS/ZrO exhibited noteworthy electrocatalytic activity toward both analytes, with well-resolved oxidation peaks that allowed simultaneous detection without mutual interference. Under optimized conditions, the sensor displayed a linear response for TPN from 0.5 to 570 & micro;M and for CTN from 0.3 to 610 & micro;M, with corresponding detection limits of 0.045 and 0.028 & micro;M, respectively. The fabricated electrode demonstrated good reproducibility, stability, sensitivity, and selectivity in the presence of common interfering species. Moreover, the biosensor was successfully applied to determine TPN and CTN in pharmaceutical formulations and biological samples, highlighting its potential for practical electroanalytical applications.
