Elemental Analysis Research Articles

Improving CO2 Fixation with Epoxides by Replacing Zirconium by Hafnium in UiO66 MOFs

AbstractThe impact of replacing Zr4+ with Hf⁴⁺ as the metal site on CO₂ adsorption and catalytic activity in CO₂ fixation reaction with epoxide under mild conditions was investigated in UiO66‐NH₂ grafted with carbodiimides N,N′‐dicyclohexylcarbodiimide (DCC) and N,N′‐diisopropylcarbodiimide (DIC) (UiO66(M)‐DCCBr and UiO66(M)‐DICBr; M = Zr and Hf). Leveraging on Hf⁴⁺’s greater oxophilicity and stronger M—O bonds, Hf‐based UiO66‐NH2 materials exhibited increased CO₂ adsorption capacity, influencing the catalytic performance in CO₂ fixation with epoxides. The materials were characterized by multiple techniques such as PXRD, FTIR, TGA, SEM, elemental analysis, as well as N₂ and CO₂ adsorption equilibrium measurements. UiO66(Hf)‐DCCBr and UiO66(Hf)‐DICBr demonstrated superior activity compared to their Zr‐based counterparts with high yield and TOF (14.6 and 11.9 h⁻¹, respectively) under milder conditions (0.1 MPa, 90 °C, 16 h, co‐catalyst‐free and solvent‐free). These findings underscore the pivotal role of unsaturated metal sites in enhancing the catalytic efficacy of guanidinium ionic UiO66‐NH₂ materials. Moreover, these catalysts exhibit excellent thermal stability and can be recycled and reused at least five times without a noticeable reduction in their catalytic efficiency.

The Characteristics of Hydrodeoxygenation of Biomass Pyrolysis Oil over Alumina-Supported NiMo Catalysts

The hydrodeoxygenation (HDO) of biomass pyrolysis oil (BPO) was evaluated in the presence of two commercial alumina-supported transition metal catalysts, NiMo/alumina-1 (NM1) and NiMo/alumina-2 (NM2). The study explored two characteristic aspects: how HDO reaction conditions affected the oxygen content, density, and boiling point distribution of BPO with varying temperature and HDO reaction time, and the roles of catalysts. Characterizations of HDO-treated oils included elemental analysis, GC-MS, SIMDIS, 13C NMR, and 1H NMR, and characterizations of catalysts included NH3-TPD, XRF, and TPO-MS analysis. The results show that both NM1 and NM2 catalysts removed oxygenated compounds effectively, which led to decreases in density and shifts toward higher boiling point distributions of BPO. Compared to the NM1 catalyst, NM2 had a higher acidity and enhanced HDO activity. The best HDO reaction performance was achieved in the presence of the NM2 catalyst at 300 °C. Furthermore, HDO reactions showed a significant amount of CO2, CH4, C2H6, and C3H8, which suggests that HDO reactions proceeded via a series of reactions of decarboxylation, water–gas shift, and methanation. In addition, hydrocarbon fraction tests suggested a favorable potential for the blending of HDO-treated biomass pyrolysis oil (HDO-BPO) with petroleum-derived fractions.

Metallurgical study of copper objects from the Varanasi region, India (1200 BCE to 400 CE)

AbstractThis study aims to investigate ancient Indian copper metallurgy based on selected copper artifacts recovered from India. The collected objects belong to the period c. 1200 BCE to 400 CE. The paper discusses the analysis of seven artifacts from two archaeological sites (Agiabir and Raipura) around the Varanasi region in Northern India. The study explores the manufacturing techniques and alloying practices applied to the artifacts by analyzing the excavated objects using optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray fluorescence spectroscopy. The microstructure of the artifacts revealed the practice of annealing, casting, and forging. Elemental analysis of these objects shows that most of the artifacts are copper–tin alloys, having varying amounts of tin. This study indicates that the tin amount has been varied according to the object's functionality.

Design and Characterization of Novel Naphthalimide Fluorescent Probe for H2S Detection in Human Serum.

In this work, a novel fluorescent probe (compound 2) based on the Intramolecular charge transfer (ICT) mechanism was designed and successfully applied to determine H2S in human serum. Fluorophore 1,8-naphthalimide was chosen, while the azide group was the recognition group for H2S determination. By introducing p-toluidine moiety on the imide part of the molecule, a donor-acceptor (D-A) conjugated system was formed. Prepared compound 2 was characterized using 1H, 13C NMR spectroscopy, and elemental analysis. Fluorescence spectra measurements were carried out, and several influences on fluorescence intensity were investigated, including pH, time dependence, selective response, and influence of H2S concentration. Conducted experiments, including the calculated detection limit of the prepared fluorescent probe, which was found to be 0.085 µmol·L- 1, showing that compound 2 could be applied for H2S detection in human serum and could detect low micromolar concentrations of H2S. Finally, compound 2 was successfully applied to detect H2S in a human serum sample, whereby the concentration of H2S was 17.2 µmol·L- 1. The accuracy of the H2S determination was confirmed with the standard addition method.

Giant {Mo132} polyoxometalate isolated with diverse organic cations: a systematic proton conductivity study.

The development of efficient and stable proton conductors is a pivotal area of research due to their transformative potential in alternative energy technologies. Recently, there has been a surge of interest in synthesizing proton conductors based on polyoxometalate (POM) materials, attributed to their highly negatively charged and oxygen-rich surfaces. In this study, we report on a highly water-soluble giant POM, (NH4)42[Mo132O372(CH3COO)30(H2O)72]·ca.300H2O·ca.10CH3COONH4 (designated as {Mo132}), which was rendered insoluble in water by exchanging its ammonium cations with larger organic cations, specifically histidinium, pyridinium, bipyridinium, and methyl viologen, resulting in His-Mo132, Py-Mo132, Bpy-Mo132 and MV-Mo132, respectively. These ion-exchanged compounds were thoroughly characterized through comprehensive spectral analyses, elemental analyses and microscopic studies. The substitution with organic cations containing nitrogen centres not only rendered {Mo132} insoluble, but also increased the number of proton hopping sites, thereby enhancing proton transport. Consequently, His-Mo132, Py-Mo132, Bpy-Mo132 and MV-Mo132 demonstrated impressive proton conductivity. Among these, Py-Mo132 stood out with a proton conductivity of 1.07 × 10-2 S cm-1 under 98% relative humidity at 80 °C. All four compounds exhibited proton conduction predominantly via the Grotthuss mechanism. Furthermore, stability assessments of these Mo132-based proton conductors were conducted under operational conditions to evaluate their performance in practical applications.

SYNTHESIS, CHARACTERIZATION AND INVITRO-ANTIMICROBIAL ACTIVITIES OF Ni (II) AND Fe (II) COMPLEXES OF SOME HYDRAZONE LIGANDS

hydrazone which are compounds that have N-N bond in addition to –C=N- bond of well-known Schiff’s bases. They are formed by the reaction of carbonyl compounds (ketones or aldehydes) with hydrazides or its derivatives. They form coordination compounds with almost all transition elements, forming various geometries. The present work focuses on the synthesis and characterization of Ni (II) and Fe (II) complexes of some hydrazone ligands. For this purpose, three (3) different hydrazone ligands were synthesized, by reacting different types of hydrazide derivatives with carbonyl compounds (ketones or aldehydes). Each of these ligands were used to formed complexes with Ni (II) and Fe (II), using their hexahydrated metal salts. The complexes were characterized using; IR spectroscopy, UV-Visible spectroscopy, elemental analysis, conductivity measurement and magnetic susceptibility measurement.

Synthesis, Crystallographic Structure, Stability, and HSA-Binding Affinity of a Novel Copper(II) Complex with Pyridoxal-Semicarbazone Ligand

Copper–semicarbazone ligands have been extensively investigated for several medicinal applications. In this contribution, a novel copper(II) complex with a pyridoxal–semicarbazone ligand, [Cu(PLSC)Cl(H2O)](NO3)(H2O), was synthesized and characterized by X-ray crystallography, elemental analysis, UV-VIS, and FTIR spectroscopies. The stabilization interactions within the structure were assessed using the Hirshfeld surface analysis. The crystallographic structure was optimized at the B3LYP/6-311++G(d,p)(H,C,N,O)/LanL2DZ(Cu) level of theory. A comparison between the experimental and theoretical bond lengths and angles was undertaken to verify the applicability of the selected level of theory. The obtained high correlation coefficients and low mean absolute errors confirmed that the optimized structure is suitable for further investigating the interactions between donor atoms and copper, along with the interactions between species in a neutral complex, using the Quantum Theory of Atoms in Molecules approach. The electrostatic potential surface map was used to reveal distinct charge distributions. The experimental and calculated FTIR spectra were compared, and the most prominent bands were assigned. The interactions with human serum albumin (HSA) were assessed by spectrofluorometric titration. The spontaneity of the process was proven, and the thermodynamic parameters of binding were calculated. Molecular docking analysis identified the most probable binding site, providing additional insight into the nature of the interactions.

Growth, elemental, spectral, linear, photoconductivity, dielectric, thermal, and Z-scan analysis of benzotriazolium oxalate dihydrate single crystal for third-order harmonic generation applications

Growth, elemental, spectral, linear, photoconductivity, dielectric, thermal, and Z-scan analysis of benzotriazolium oxalate dihydrate single crystal for third-order harmonic generation applications

Catalyst-Free Depolymerization of Methanol-Fractionated Kraft Lignin to Aromatic Monomers in Supercritical Methanol

Lignin is considered a renewable source for the production of valuable aromatic chemicals and liquid fuel. Solvent depolymerization of lignin is a fruitful strategy for the valorization of lignin. However, Kraft lignin is highly prone to produce char (a by-product) during the hydrothermal depolymerization process due to its poor solubility in organic solvents. Therefore, the minimization of char formation remains challenging. The purpose of the present study was to fractionate Kraft lignin in methanol to obtain low-molecular-weight fractions that could be further depolymerized in supercritical methanol to produce aromatic monomers and to suppress char formation. The results showed that the use of methanol-soluble lignin achieved a bio-oil yield of 45.04% and a char yield of 39.6% at 280 °C for 2 h compared to 28.57% and 57.73%, respectively, when using raw Kraft lignin. Elemental analysis revealed a high heating value of 30.13 MJ kg−1 and a sulfur content of only 0.09% for the bio-oil derived from methanol-soluble lignin. The methanol extraction process reduced the oxygen content and increased the hydrogen and carbon contents in the modified lignin and bio-oil, indicating that the extracted lignin fraction had an enhanced deoxygenation capability and a higher energy content. These findings highlight the potential of methanol-soluble Kraft lignin as a valuable resource for sustainable energy production and the production of aromatic compounds.

Chemical Functionalization of Cellulose Nanofibrils with 2-Aminoethyl Hydrogen Sulfate.

The chemical functionalization of cellulose nanofibrils (CNFs) was carried out using 2-aminoethyl hydrogen sulfate as the reagent under various experimental conditions via a bimolecular nucleophilic substitution (SN2) reaction. The functionalized CNFs were characterized by Fourier transform infrared spectroscopy-attenuated total reflectance. The results indicate that the chemical modification was successful, as evidenced by the presence of a band at 1540 cm-1, corresponding to the N-H bond of the amine group. Elemental analysis revealed a nitrogen content of 0.45%, and the degree of substitution was calculated to be 0.053 under the optimal reaction conditions. Atomic force microscopy analysis showed no significant changes in the morphology of the CNFs. X-ray diffraction patterns demonstrated a decrease in the crystallinity index, from 80.8% to 71.8%. Thermogravimetric analysis showed a slight reduction in thermal stability (onset temperature decreased from 229.4 to 227.5 °C) for the modified CNFs compared to the unmodified samples. Differential scanning calorimetry results indicated no significant effect of the modification on thermal behavior, with both modified and unmodified samples displaying similar thermal profiles, although the modified samples exhibited slightly higher thermal stability.

Preparation of aminated hardwood kraft lignin by Mannich reaction and its structural and thermal characterization

This study investigated the characteristics of aminated kraft lignin (AKL) prepared from the Mannich reaction of hardwood kraft lignin (KL) and diethylenetriamine (DETA) for future application in dye removal. Three aminated samples—AKL-3.5, AKL-7.5, and AKL-15—were prepared using different amounts of DETA (3.5, 7.5, and 15 mmol). The morphology, chemical, and thermal properties of AKLs were investigated through various instrumental analyses and compared with KL. Elemental analysis showed that AKL-15 contained the highest nitrogen content (8%). Based on scanning electron microscopy (SEM), AKLs exhibited a smoother surface compared to KL and aggregated into clusters. Infrared, X-ray photoelectron and 2D heteronuclear single quantum coherence nuclear magnetic resonance spectroscopy confirmed the successful introduction of primary and secondary amines, and C = N functionality into the lignin structure.31P NMR indicated a decrease in hydroxyl group contents of guaiacyl and p-hydroxyphenyl units and an increase in C5 amine-substituted units for AKL-15. Thermal analyses (TGA and DSC) indicated that AKLs were thermally less stable and reduced glass transition temperature (Tg) than KL. These findings contribute to the limited literature on the amination of hardwood lignin, as most amination studies focus on softwood and grass lignins.

The Integration of Microwave-Synthesized Silver Colloidal Nanoparticles into Poly (Lactic Acid)-Based Textiles as Antimicrobial Agents via Pre- and Post-Electrospinning Processes.

This study introduces a novel method to enhance the antibacterial functionality of electrospun nanofibrous textiles by integrating silver nanoparticles (AgNPs) into poly (lactic acid) (PLA) fabrics through pre- and post-electrospinning techniques. AgNPs were incorporated into hydrophobic and modified hydrophilic PLA textiles via pre-solution blending and post-solution casting. A PEG-PPG-PEG tri-block copolymer was utilized to enhance hydrophilicity and water stability, while AgNPs served as antibacterial agents. Morphological analyses confirmed uniform, smooth, and beadless nanofibers with diameters between 435 and 823 nm. Energy-dispersive X-ray spectroscopy spectra and elemental analysis verified the successful incorporation of AgNPs, with higher Ag content in the post-electrospinning samples. Contact angle measurements showed an improved hydrophilicity of the modified PLA textiles, absorbing water droplets within 2 s. The X-ray crystallography patterns confirmed the amorphous structures of the PLA and PEG-PPG-PEG, with reduced crystallinity in the samples containing AgNPs. Thermal analysis indicated lower decomposition temperatures for the hydrophilic samples due to the plasticizing effects of PEG-PPG-PEG on PLA. Mechanical testing showed comparable tensile strengths but reduced elongation in the post-treated samples. The antibacterial efficacy was assessed against various bacterial strains, with post-electrospinning AgNP incorporation showing the most effective antibacterial properties. The results indicate that integrating electrospinning and nanofiber modification techniques expands the applications of PLA-based protective fabrics for disabled individuals.

The Energy Potential of Residual Biomass Gasification Integrated with Internal Combustion Engine in Córdoba, Colombia using Artificial Neural Network Techniques

In this study, the energy potential of waste biomass gasification integrated to internal combustion engine in Cordoba, Colombia was investigated using artificial neural network techniques. A model was trained with proximate and elemental analysis data of different biomasses and this model was used to estimate the gasification potential of the four most abundant biomasses in Cordoba. The model developed achieved an adjusted determination coefficient (R2) of 0.9293 for validation and 0.9048 for training, demonstrating high predictive accuracy. The results indicate that temperature positively influences energy generation potential, while moisture content and air-to-fuel ratio have a negative impact. Among the biomass types analyzed, cassava stands out with the highest energy potential, exceeding 9 GWh/year, followed by plantain at approximately 3 GWh/year, maize cobs below 2 GWh/ year, and rice husk with <0.5 GWh/year. These findings provide critical insights for optimizing biomass gasification processes and harnessing regional biomass resources for energy generation.

SYNTHESIS, CHARACTERIZATION AND CHOLINESTERASE INHIBITORY EFFECTS OF IBUPROFEN-BASED SPIROTHIAZOLIDINONES

Objective: A novel class of spirothiazolidinone derivatives were designed, synthesized, and assessed as possible acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors for Alzheimer's disease therapy. Material and Method: In this study, novel spirocyclic compounds were synthesized by one-pot reaction. IR, 1H NMR, 13C NMR, LC-MS and elemental analysis techniques have all been used to clarify the chemical structures of the compounds. AChE and BuChE inhibitory effects of compounds (4a-e and, 5a-e) were assayed according to Ellman’s method using galantamine as reference. Result and Discussion: According to the inhibition data, compound 4e demonstrated the most promising activity against AChE, with an IC50 value of 39.53±1.94 µM, while compound 4b exhibited the most potential against BuChE, with an IC50 value of 95.97±1.79 µM.

Design, Synthesis, Molecular docking and Biological Evaluation of Novel Leucine Derived Sulfamoyl Pentanamides as Antimicrobial and Antioxidant Agents

The preponderance of microbial and oxidative stress-mediated diseases is quite alarming. The need for novel drug development is highlighted by the fact that antimicrobial resistance is rising and many current antioxidant drugs only provide little symptomatic alleviation. The aim of this work was to synthesize leucine derived sulfamoyl pentanamides with antioxidant and antimicrobial activities. New leucine-based sulfamoyl pentanamides were synthesized and elemental analysis, 1H-NMR, 13C-NMR, and FTIR were used to elucidate their structures. They underwent molecular docking investigations as well as in vitro antioxidant and antimicrobial activity analyses. Compound 5a (0.60 gm/ml) was the most active compound against Pseudomonas aeroginosa, whereas compound 5f (0.30-0.40 mg/ml) was the most effective antibacterial agent against E. Coli, S. typhi, S. aureus, and B. subtilis. The compounds with the best antifungal activity against C. albican and A. niger, respectively, were 5g (0.80 mg/ml) and 5e (0.50 mg/ml). In the in vitro antioxidant assessment, compounds 5g (1.174µg/ml) and 5h (1.172µg/ml) exhibited similar antioxidant activity to ascorbic acid (IC50 1.001µglml). In addition, most of the target compounds have relatively strong antibacterial, antifungal, and antioxidant potentials, according to molecular docking study. Since every target compound complied with Lipinski's rule of five, it is likely that they might be used as therapeutic candidates to treat oxidative stress-related illnesses and microbial infections.

Biocomposite adsorbent (cross-linked chitosan + algae + montmorillonite) for methyl violet 2B dye removal: statistical modelling and optimisation

ABSTRACT Herein, a biocomposite of crosslinked chitosan polyethylene glycol diglycidyl ether (CS-PEDGE), montmorillonite (MMT), and food-grade algae (FGA) was successfully prepared by a hydrothermal technique. The resulting absorbent (CS-PEDGE/FGA/MMT) was assessed for its adsorption property with methyl violet 2B (MV 2B) a toxic cationic dye. The physicochemical properties of CS-EDGE/FGA/MMT were assessed via various analytical techniques, including BET, Elemental analysis, pHpzc, and spectroscopy (FTIR, XRD, SEM-EDX). The influence of three adsorption variables, namely adsorbent dose (A: 0.02–0.1 g/100 mL), solution pH (B: 4–10), and contact time (C: 10–420 min) on the rate of MV 2B dye removal was examined using the Box-Behnken design (RSM-BBD). The findings from the equilibrium isotherm and kinetic analyses suggest that the MV 2B dye adsorption onto the biocomposite surface follow the Freundlich model and pseudo-second-order kinetic models. The biocomposite adsorbent exhibits a maximum dye adsorption capacity (q max ) of 94.2 mg/g. The proposed MV 2B dye adsorption mechanism involves hydrogen bonding, n-π stacking, and electrostatic forces. This research demonstrates the unique structure and outstanding adsorption properties of CS-EDGE/FGA/MMT, which offers a viable solution for removal of detrimental MV 2B dyes from aqueous media.

The Amination of Waste Newsprint Paper with Various Aminating Agents (Ammonia Water, Ethylenediamine, and Diethylenetriamine) to Improve the Sorption Efficiency of Anionic Dyes.

This study aimed to investigate the effect of aminating waste newsprint paper with different aminating agents (ammonia/ammonia water, ethylenediamine, and diethylenetriamine) for the sorption efficiency of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) dyes. To increase the amination efficiency, the paper material was pre-activated with epichlorohydrin. The scope of this study included the characterization of the sorbents tested (FTIR, elemental analysis, BET surface area, porosity, and pHPZC), determination of the influence of pH on dye sorption efficiency, sorption kinetics, and the maximum sorption capacity of the dyes. The study results showed that amination with ethylenediamine and diethylenetriamine introduced 87% and 194% more amine groups into the sorbent's structure compared to the treatment with ammonia. The sorption efficiency of RB5 and RY84 on the sorbents tested was the highest in the pH range of 2-3. The sorption equilibrium time ranged from 90 to 150 min and was longer in the case of the unmodified sorbents. The experimental data from the study were best described by the pseudo-second-order model and the Langmuir 1 and 2 models. Amination had a very strong effect on the sorption capacity of newsprint. For example, the sorption capacity of newsprint paper towards RB5 (Qmax = 7.12 mg/g) increased after amination with ammonia, ethylenediamine, and diethylenetriamine to the value of Qmax = 182.78 mg/g, Qmax = 202.7 mg/g, and Qmax = 231.5 mg/g, respectively.

Evaluating the Nutritional and Chemical Composition of Treculia Africana and Vigna Subterranea L. Seeds Collected from Kogi State, Nigeria

This study aims to investigate the nutritional composition of two underutilized leguminous crops, namely Treculia africana and Vigna subterranea seeds, collected from Kogi state, Nigeria. The study analysed their proximate composition, mineral content, and amino acid profile using standard analytical methods. Additionally, the chemical composition of the sample was determined using gas chromatography-mass spectroscopy. The results showed that there were significant differences (P≤0.05) in the legume samples. However, V. subterranea seeds had the least moisture content (12.90±0.81 %) as well as the highest crude fat content, crude fiber content, crude protein and ash content at 15.70±0.41 %, 5.06±0.16 %, 27.86±0.25 % and 3.23±0.50 %, respectively. The elemental analysis in mg/100g indicated that the samples contained appreciable levels of essential minerals. T. africana had the highest magnesium, phosphorus, sodium, potassium and iron concentrations of 190.03±1.70 mg/100g, 315.95±1.60 mg/100g, 32.61±1.82 mg/100g, 1941.53±2.61 mg/100g and 39.50±1.73 mg/100g, respectively, while calcium (58.46±1.63) was most abundant in V. subterranea The samples were also rich in amino acids, which are the building blocks of protein. However, V. subterranea was the richest in amino acid content, as it had 33.07±2.22 g/100g and 46.01±4.24 g/100g, for essential and non-essential amino acids, respectively. The GC-MS characterization of the chemical composition of the samples showed that myristic acid (48.1) was the most abundant in T. africana, while ethyl palmitate (31.17) was the most abundant in V. subterranea. Overall, the results suggest that these legume samples are rich sources of both nutritional and pharmaceutical properties beneficial for human consumption.

Synthesis and Properties of Thermostable Energetic Benzotriazines.

In an effort to balance energy and molecular stability effectively, several energetic compounds (3-6) based on benzotriazine were designed and synthesized. These structures were comprehensively characterized using NMR, IR, and elemental analysis, with compounds 3, 5, and 6 further confirmed by single-crystal X-ray diffraction. Notably, 3-amino-5,7-dinitrobenzo[e][1,2,4]triazine 1-oxide (5), which features a face-to-face crystal stacking arrangement, exhibits good detonation velocity (Dv = 8050 m/s), a high thermal decomposition temperature (Td = 290 °C), and low sensitivities (impact sensitivity >40 J, friction sensitivity >360 N). The preparation of compound 5 was further optimized by using a commercially available flow microreactor system, achieving an improved yield of 62%. Overall, the comprehensive properties of compound 5 make it a promising candidate for heat-resistant explosive applications.

Optical, structural, and vibrational properties of In2S3 thin films by sputtering-RF for applications in optoelectronics devices

Abstract Experimental results on the crystalline orientation properties, energy band gap, and Raman vibrational modes of Indium Sulfide (In2S3) thin films grown by Sputtering in Radio Frequency mode are presented. The In2S3 thin films were grown at 25, 200, and 300°C; thereafter the samples were thermally annealed in air for 30 min at 450°C, in order to improve their crystalline and physical properties. Energy dispersive X-ray spectroscopy results showed that the β-In2S3 crystallographic phase became predominant as the substrate temperature increased. For the optical transmittance spectra, it was observed that the deposited In2S3 thin films at 300°C and with thermal annealing showed an increase in their band gap energy of nearly 60 meV. The direct energy band gap of In2S3 films varied in the range of 2.76–2.82 eV. The scanning electron microcopy image and elemental analysis shows a better morphology, and an increase in O and Sn when the In2S3 samples were subjected to thermal annealed and the substrate temperature increased, respectively. Photoluminescence spectra were obtained at room temperature and showed two emission bands around 1.75 (709 nm) and 2.35 eV (527 nm), one related to interstitial indium donor sites (Ini) and oxygen acceptor vacancies (OVs), and the second to an emission band corresponding to the transition sulfur donor-indium acceptor. As the substrate temperature increased and thermal annealing of In2S3 was performed, the 1.75 eV emission bands increased in intensity with respect to the 2.35 eV band. From the Raman measurements, it was observed that the vibrational peaks were better defined as the substrate temperature increased and In2S3 underwent thermal annealing. In addition, to study the spinel-like defect structure, the peaks corresponding to the five main vibrational modes of In2S3 were identified as the Alg mode, Eg mode, and three modes of the F2g.