This study provides a comprehensive analysis of lemon peel (LP) combustion behaviour using combined physicochemical characterization and non-isothermal thermogravimetric kinetics. To achieve this, LP was characterized for its proximate and ultimate composition, with its structure analysed via FTIR, XRD, and SEM. Thermogravimetric analysis (TGA) was then performed at high heating rates (20–80 K min⁻¹) to investigate combustion stages, and kinetic and thermodynamic parameters were determined using six model-free and one model-fitting method. The results revealed a high heating value (23.02 MJ kg⁻¹) and high volatile matter (73.2 wt%), establishing LP’s significant energy potential. TGA displayed four distinct decomposition stages corresponding to dehydration, pectin/hemicellulose, cellulose, and lignin/char combustion. Kinetic analysis yielded activation energies that varied with conversion, peaking at approximately 304 kJ mol⁻¹, and a three-dimensional diffusion (D3) mechanism was identified as the rate-limiting step. In conclusion, while its high energy content and low nitrogen (1.26 wt%) and sulphur (0.20 wt%) content make LP an attractive low-emission biofuel, its viability is challenged by a high potassium concentration in the ash (34.8 wt% K₂O), posing a severe risk of slagging. This study provides the comprehensive combustion kinetic data for LP at high heating rates, which is essential for designing appropriate energy conversion technologies and ash management strategies.

The advancement of optical materials has garnered significant interest from the global scientific community in the pursuit of efficient photocatalysts for the purification of water using light. This challenge, which cannot be addressed using traditional methods, is tackled in the present study utilizing unconventional approaches. This study presents the fabrication of an effective photocatalyst using an unconventional approach that employs explosive reactions. This method successfully produces 3D nanostructures composed of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and silica–alumina nanoparticles at temperatures below 270 °C. Gold-supported silica–alumina–CNT–CNF nanostructures were synthesized and characterized using XRD, TEM, SEM, and EDX, in addition to mapping images. To study and determine the photoactivity of these produced nanostructures, two well-known photocatalysts—titanium dioxide and zinc oxide—were synthesized at the nanoscale for comparison. The results showed that the presence of CNTs and CNFs significantly reduced the band gap energy from 5.5 eV to 1.65 eV and 3.65 eV, respectively, after modifying the silica–alumina structure. In addition, complete degradation of green dye was achieved after 35 min of light exposure using the modified silica–alumina structure. Additionally, the surface properties of the modified silica–alumina had a positive role in accelerating the photocatalytic decomposition of the green dye NGB. A kinetic study confirmed that the modified silica–alumina functions as a promising additive for optical applications, accelerating the photocatalytic degradation of NGB to a rate three times faster than that of the prepared titanium dioxide and six times that of the prepared zinc oxide.

This study provides a comprehensive analysis of peanut shell (PnS) combustion behavior using combined physicochemical characterization and non-isothermal thermogravimetric kinetics. To evaluate its potential as a sustainable solid biofuel, PnS was characterized for its proximate and ultimate composition, with its fiber structure analyzed via Van Soest methods and functional groups identified via FTIR spectroscopy. Thermogravimetric analysis (TGA) was performed at high heating rates ($20,40,60$, and $80 \mathrm{K}{ \mathrm{m}\mathrm{i}\mathrm{n}}^{-1}$) to investigate combustion stages under oxidative conditions. The results established PnS as a high-potential energy source, revealing a significant volatile matter content ($65.30 \mathrm{w}\mathrm{t}\%$) and an exceptionally high heating value ($20.87 \mathrm{M}\mathrm{J} {\mathrm{k}\mathrm{g}}^{-1}$), which surpasses many standard agricultural residues. The proximate analysis also indicated a moisture content of $9.61\%$ and an ash content of $6.59\%$. TGA profiles displayed distinct decomposition stages, with the primary devolatilization occurring between 500 and 700 K. Kinetic analysis was conducted using six model-free methods: Friedman (FR), Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), Starink (STK), Kissinger (K), and Vyazovkin (VY) and the Coats-Redfern model-fitting method. The apparent activation energy $\left({\mathrm{E}}_{\mathrm{a}}\right)$ was found to vary with conversion $\left(\mathsf{\alpha }\right)$, reflecting the complex degradation of the lignocellulosic matrix (47.86% cellulose, $28.4\%$ lignin). The activation energy values ranged from approximately $23 \mathrm{k}\mathrm{J}{ \mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$ (VY method at low conversion) to $187 \mathrm{k}\mathrm{J}{ \mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$ (FR method at $\mathsf{\alpha }=0.5$). Model-fitting analysis identified the three-dimensional diffusion (D3) model as the governing reaction mechanism. Thermodynamic analysis indicated positive enthalpy ($\Delta \mathrm{H}:70.7-181.8 \mathrm{k}\mathrm{J}{ \mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$) and Gibbs free energy ($\Delta \mathrm{G}$: $116.2-216.7 \mathrm{k}\mathrm{J}{ \mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$), with predominately negative entropy ($\Delta \mathrm{S}$), confirming the endothermic and non-spontaneous nature of the reaction activation.

This theoretical study investigates the electrical conductance of non-conjugated cyclic molecules featuring three terminal anchoring groups at the single-molecule level. Density Functional Theory (DFT) calculations demonstrate that the conductance of the symmetric and asymmetric cyclic structures C₆C₆, C₆C₈, C₆C₁₀, C₈C₈, C₈C₁₀, and C₁₀C₁₀ (where the numbers indicate the lengths of the upper and lower branches) decreases with increasing molecular length, independent of the anchor group chemistry. Distinct trends are observed across molecular series: the 6-unit branch—defined as molecules containing a common six-carbon saturated segment (e.g., C₄C₆, C₆C₆, C₆C₈, C₆C₁₀)—exhibits a non-conventional pattern, whereas the 8-unit and 10-unit branches display parabolic and conventional length-dependent behavior, respectively. A key finding is that cyclic molecules with identical total CH₂ units exhibit nearly identical conductance values, irrespective of structural symmetry. These theoretical predictions are strongly supported by previously reported scanning tunneling microscopy break-junction measurements, establishing a fundamental structure–property relationship for sigma-conjugated molecular systems. These findings provide critical design principles for developing advanced molecular-scale electronic devices.

In this DFT-based theoretical study, I investigate the conductance superposition in π-conjugated molecular junctions containing single- and double-backbone transport pathways terminated with thiol (–SH), amine (–NH₂), and direct carbon (–C) anchoring groups. The electrical conductance is evaluated using density functional theory combined with quantum transport calculations to systematically compare the transport properties of single- and double-backbone molecular junctions. The results demonstrate that introducing a second molecular backbone consistently enhances the electrical conductance through constructive quantum interference between parallel transport pathways. However, the magnitude of this enhancement depends strongly on both the molecular structure and the anchoring groups, leading to systematic deviations from classical conductance additivity. Quantitative comparison with the classical (\({2G}_{1}\)) and ideal quantum (\({4G}_{1}\)) reference models shows that the conductance of double-backbone junctions consistently exceeds the classical limit while remaining below or approaching the ideal quantum limit, depending on the molecular system and anchoring group. For thiol-anchored junctions, the predicted conductance trends are in good agreement with previously reported scanning tunneling microscopy break-junction measurements, supporting the predictive capability of the computational approach. Overall, this study establishes a general computational framework for evaluating conductance superposition in molecular junctions and demonstrates that coherent quantum interference, together with molecular structure and anchoring chemistry, governs charge transport beyond the predictions of classical circuit theory. These findings provide fundamental insight into charge transport in molecular-scale electronic systems and offer design guidelines for the development of future high-conductance molecular junctions based on multi-pathway architectures.

Charge transport in single-molecule junctions depends strongly on molecular length, backbone conjugation, and molecule–electrode coupling. In this work, density functional theory (DFT) combined with quantum transport calculations is used to investigate length-dependent conductance in oligo (phenylene ethynylene) (OPE) molecular wires terminated with amine (–NH₂), thiol (–SH), and direct carbon (–C) contacts. For all anchoring groups, conductance decreases exponentially with increasing molecular length. The extracted attenuation factors show a clear dependence on anchoring groups: thiol- and carbon-terminated junctions exhibit similar decay constants (β ≈ 0.23–0.24 Å⁻¹), whereas amine-terminated junctions display a smaller value (β ≈ 0.14 Å⁻¹). The theoretical trends are consistent with previously reported STM, MCBJ, and CP-AFM measurements for OPE junctions. Finally, a theoretical scaling relation is derived that quantitatively connects conductance decay in alkane and OPE molecular wires. The proposed relation reproduces both theoretical calculations and experimental datasets with high accuracy (R²≈ 0.89–0.93) and provides a theoretical framework for understanding conductance scaling across structurally distinct molecular wires.