Publications

Abstract Established applicability of biocomposites in the field of automotive, construction and structural industries has led to a hope to utilize them in the near future for further applications such as food packaging and lightweight coatings. Due to their global abundance, natural fibers and starch have been the most widely tested and used raw materials for use as the bio-composite reinforcements. Here in this work, composites based on corn starch (CS) and vetiver cellulose fibers (VCF) are fabricated using the solution casting method. Alpha-cellulose was synthesized from the vetiver roots post converted into nano-cellulose using the ball milling. Various compositions of 0%, 5%, 10%, 15% and 20% (by weight) of this α-cellulose were introduced as the reinforcement to commercially available corn starch matrix. Tensile tests for the fabricated composites were done in accordance with the American Standard for Testing and Materials standard procedure. Crystallinity and failure morphology of the composites was studied using the X-Ray Diffraction techniques and scanning electron microscopy, respectively. Water absorption capacity test, Fourier-transform infrared spectroscopy analysis, and determination of contact angle of the films were also done to evaluate the film properties. Results reveal that the incorporation of vetiver cellulose fiber in the starch enhances the mechanical properties of bio-composites. Also, the water absorption capacity and the contact angle decreased and increased, respectively; thereby predicting the composites application as a lightweight food packaging material.

Abstract The aim of the presented work was to assess the potential of Medicago polymorpha extract to synthesize silver nanoparticles (AgNPs) as a green method. It was a simple one-step synthesis approach and the product obtained was characterized by UV-visible spectroscopy, Fourier transform infrared (FTIR), powder X-ray diffraction, thermogravimetric analysis, and field-emission scanning electron microscopy (FE-SEM). At room temperature, the optimum time for the completion of the reaction (i.e. the formation colloidal solution) was just 5 min. FE-SEM images showed that AgNPs were predominantly in spheres, whereas FTIR spectrum analysis inferred that gallic acid present in the extract initially reduced silver ions to elemental silver. The carboxylic and hydroxyl groups of biomolecules present in the extract stabilized AgNPs by passivating the surface to prevent aggregation, resulting in uniform distribution. The antibacterial activity of synthesized AgNPs showed effective inhibitory effects against waterborne pathogens, including Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), at a minimum inhibitory concentration of 10 μg/ml. Membrane permeability and respiration studies were also performed to assess the surface role of the synthesized AgNPs. The prepared AgNPs exhibited excellent antioxidant activity and catalytic reduction of methyl orange with a rate constant of 6.8×10 −3 s −1 .

Here, an important attempt has been employed for the development and applications of Al doped ZnO (Al.ZnO) nanoparticles using hydrothermal method at room conditions. The structural, optical, and chemical properties of the low-dimensional (average diameter, 64.0±10.0 nm) doped Al.ZnO nanoparticles were exemplified using various techniques such as UV/visible, FT-IR, Raman spectroscopy, x-ray powder diffraction (XRD), and Field-emission scanning electron microscopy (FE-SEM) etc. Al.ZnO is an interesting doped nanoparticles for implementation in chemical sensing by reliable I-V method, where hazardous chemical (phenyl hydrazine, PhHyd) is used as a target chemical. The sensor performances are investigated using Al.ZnO nanoparticles embedded onto silver electrodes (AgE, active surface area, 0.0216 cm2), which shows the sensitivity, stability, and reproducibility of the sensor improved significantly. In analytical investigation, the calibration plot is linear over the large concentration range (10.0 µM to 0.05M), where the sensitivity is 1.1432 ± 0.10 µAcm-2mM-1 with a detection limit (LOD) of 1.215 ± 0.02 µM based on signal to noise ratio in short response time. Therefore, it is concluded that the morphologies and the optical features can be implemented to large-scale in transition-metal-doped semiconductor nano-materials as well as efficient chemical sensors.
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In the title compound, C(13)H(9)ClINO(4)S, the dihedral angle between the aromatic rings is 81.04 (17)°. The disposition of the I and Cl atoms attached to the two rings is anti. In the crystal, mol-ecules are connected via O-H⋯O and N-H⋯O hydrogen bonds.

NH3 is an important chemical with a wide range of applications, but its synthesis mainly relies upon the harsh Haber-Bosch process with huge CO2 emission. Electrochemical N2 reduction offers a carbon-neutral process to convert N2 to NH3 under ambient conditions, but it requires efficient and stable catalysts to drive the N2 reduction reaction. Herein, we report that a sulfur dots-graphene nanohybrid acts as a metal-free electrocatalyst for ambient N2-to-NH3 conversion with excellent selectivity. When operated in 0.5 M LiClO4, this electrocatalyst achieves a large NH3 yield of 28.56 μg h-1 mgcat.-1 and a high Faradaic efficiency of 7.07% at -0.85 V vs. reversible hydrogen electrode. Notably, it also shows good electrochemical stability.

In the crystal structure of the title compound, C(11)H(15)NO(4)S, two independent mol-ecules are present per asymmetric unit; they are dimerized through O-H⋯O hydrogen bonds between their carb-oxy groups to generate R(2) (2)(8) loops. An intra-molecular N-H⋯O link in one of the mol-ecules closes an S(5) ring. The dimers are linked by N-H⋯O and C-H⋯O hydrogen bonds to form a three-dimensional network. The C atoms of the isopropyl group of one of the mol-ecules are disordered over two orientations in a 3:1 ratio.

An Fe-doped CoP nanoarray behaves as a robust 3D monolithic multifunctional catalyst for electrolytic and hydrolytic hydrogen evolution with high activity. Its two-electrode electrolyzer needs a cell voltage of only 1.60 V for 10 mA cm^-2 water-splitting current. It also catalyzes effectively NaBH₄ hydrolysis with a low activation energy of ≈39.6 kJ mol^-1 and a hydrogen generation rate of 6.06 L min^-1 g^-1 .

Bismuth- and antimony-based materials, such as A3M2X9 and AMSX2 (A = cation, M = Bi, Sb, S = sulfur, X = halogen), are promising candidates as the counterpart to lead halide perovskite. However, the large number of different compositions and crystal structures (dimer, perovskite, etc.) has made these materials largely overlooked; thus, an intuitive evaluation strategy is required. Here, we present a comprehensive study of the energy levels (bandgap, valence band maximum, etc.) and optoelectronics (photoconductivity and charge transfer to charge transport material) of the Bi- and Sb-based materials, which include 6 crystal categories with 44 compositions, by using time-resolved microwave conductivity (TRMC). Importantly, we found an efficient hole transfer from the Sb-based materials to the hole transport materials with the inclusion of the thiophene component, leading to an improved power conversion efficiency of 2.91% for Sb2S3-containing SbSI, prepared by a novel one-step method. Our study establishes a key rule for exploring active layer compositions and designing device structures, which would accelerate the evolution of Bi- and Sb-based lead-free solar cells.

Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal-organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity.