Zinc oxide (ZnO) nanorods incorporated activated carbon (AC) composite photocatalyst was synthesized using a hydrothermal process. The AC was prepared from lapsi (Choerospondias axillaris) seed stone, an agricultural waste product, found in Nepal by the chemical activation method. An aqueous suspension of AC with ZnO precursor was subjected to the hydrothermal treatment at 140 °C for 2 h to decorate ZnO rods into the surface of AC. As-obtained ZnO nanorods decorated activated carbon (ZnO/AC) photocatalyst was characterized by various techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy. Results showed that highly crystalline hexagonal ZnO nanorods were effectively grown on the surface of porous AC. The photocatalytic property of the as-prepared ZnO/AC composite was studied by degrading methylene blue (MB) dye under UV-light irradiation. The ZnO/AC composite showed better photocatalytic property than that of the pristine ZnO nanorods. The enhanced photocatalytic performance in the case of the ZnO/AC composite is attributed to the combined effects of ZnO nanorods and AC.

Plant-mediated synthesis offers a low-toxicity route for preparing zinc oxide-based structures; however, the extent of ZnO formation depends strongly on precursor chemistry, phytochemical composition, and post-synthesis heat treatment. In this study, a stem-rich aqueous extract of Buddleja paniculata was used to precipitate a zinc-based precursor from ZnSO4·7H2O under alkaline conditions. The oven-dried precursor was coded as GB-Sample, and portions were calcined at 350 °C for 1 h and 450 °C for 2 h to produce GB-ZnO-350 and GB-ZnO-450, respectively. The materials were examined by XRD, FT-IR, and FESEM-EDX to track calcination-driven phase evolution, bonding changes, and morphology development. The XRD patterns show a progressive transition from a poorly ordered precursor to more ZnO-like calcined products, with GB-ZnO-450 exhibiting the strongest ZnO-related reflections, whereas GB-ZnO-350 already demonstrates credible ZnO-rich development under milder conditions. FT-IR spectra show suppression of precursor-associated hydroxylated/organic bands after calcination together with the emergence of Zn-O-region vibrations, although residual sulfate- and carbon-containing species remain. The FESEM images of GB-ZnO-350 reveal compact micrometre-scale secondary agglomerates assembled from anisotropic rod-/plate-like subunits, and image analysis gives a broad apparent diameter distribution of approximately 90-400 nm. Spot EDX shows Zn and O as the dominant elements with minor S and C, consistent with a ZnO-rich calcined product. The study demonstrates a coherent precursor-to-calcined transformation and shows that 350 °C for 1 h is sufficient to obtain a scientifically credible ZnO-rich material, whereas 450 °C for 2 h produces the more ZnO-like product under the present processing route.

Benzocaine (BZC; ethyl 4-aminobenzoate) is an ester local anesthetic, but its spectroscopic signatures, solvent-dependent electronic response, local reactivity, and drug-likeness have rarely been unified in a molecular framework. We optimized BZC using density functional theory at the B3LYP/6-311++G(d,p) level and performed vibrational, Raman, time-dependent density functional theory ultraviolet–visible, frontier-orbital, global/local reactivity, density of states, molecular electrostatic potential, reduced density gradient, electron localization function, localized orbital locator, thermodynamic, and SwissADME analyses. The solvent effects in water, ethanol, and acetonitrile were treated using the polarizable continuum model of the integral equation formalism. Benchmarking calculated Fourier-transform infrared frequencies against reported experimental bands yielded a mean absolute error of 35.21 \(\hbox {cm}^{-1}\), root mean square error of 53.03 \(\hbox {cm}^{-1}\), mean absolute percentage error of 1.56%, and coefficient of determination of 0.9992. Diagnostic bands include ester C=O stretching at 1749.55 \(\hbox {cm}^{-1}\), coupled C–C/C–O stretching at 1284.96 \(\hbox {cm}^{-1}\), N–H stretching at 3629.10 \(\hbox {cm}^{-1}\), and C–H stretching at 3160.41 \(\hbox {cm}^{-1}\). The longest-wavelength gas-phase transition appears at 268.30 nm, with a brighter nearby transition at 267.19 nm; solvent calculations shift the main band to 281.40-−281.53 nm and increase oscillator strength. This indicates solvent-stabilized \(\pi \rightarrow \pi ^{*}\) excitation. Polar media narrow the frontier orbital gap and increase electrophilicity, whereas electrostatic and Fukui analyses identify the carbonyl oxygen, amino group, and aromatic framework as key interaction/reactivity regions. This study provides a consolidated computational reference for interpreting BZC structure–property behavior and guiding derivative, formulation, and spectroscopic studies.