Publications

Lead is a potentially toxic element (PTE) that has several adverse medical effects in humans. Its presence in the environment became prominent due to anthropogenic activities. The current study explores the use of newly developed composite materials (organic-inorganic hybrid) based on PANI-GO-APTES for electrochemical detection of Pb²⁺ in aqueous solution. The composite material (PANI-GO-APTES) was synthesized by chemical method and was characterized with SEM, XPS, XEDS, XRD, TGA, FTIR, EIS and CV. The result of characterization indicates the successful synthesis of the intended material. The PANI-GO-APTES was successfully applied for electrochemical detection of Pb²⁺ using cyclic voltammetry and linear sweep voltammetry method. The limit of detection of Pb²⁺ was 0.0053 µM in the linear range of 0.01 µM to 0.4 µM. The current response produced during the electrochemical reduction of Pb²⁺ catalyzed by PANI-GO-APTES was also very repeatable, reproducible and rapid. The application of PANI-GO-APTES-modified GCE in real sample analysis was also established. Therefore, PANI-GO-APTES is presented as a potential Pb²⁺ sensor for environmental and human health safety.

Pathogens, such as Escherichia coli (<i>E. coli</i>) and Staphylococcus aureus (<i>S. aureus</i>), contaminate water resources and are the main causes of diseases, not just waterborne diseases. The present study aims to fabricate hybrid materials composed of polyaniline (PANI), graphene nanosheets (GNs), and carbon nanotubes (CNTs) and utilize the materials for water disinfection. Thus, a new class of hybrid nanocomposites (PANI/GN/CNTs_a-e) was fabricated under ultrasonic conditions following a well-known <i>in situ</i> oxidative polymerization technique in an aqueous acidic solution. A homogeneous mixture of GNs and CNTs (40/60 weight %) prepared at 2, 5, 10, 20 and 30% fixed ratios of GNs/CNTs was utilized in the fabrication of the nanocomposites. The structure of this new hybrid class of materials was confirmed by various characterization techniques that were utilized to corroborate their assembly. Column removal studies with bacteria indicated that the removal percentages of <i>S. aureus</i> and <i>E. coli</i> were 99.5 and 99.2%, respectively, using PANI/GN/CNTs_e. The bacterial count is an indication of bacterial removal after and before adsorption. Additionally, the data indicated clear synergic effects among the nanocomposites. Reuse studies revealed that the same percentage of adsorption was obtained for four cycles, which shows the PANI/GN/CNTs_e nanocomposites can be reused and recycled for a number of cycles with almost the same bacterial adsorption capability.

A highly symmetrical, 24-faceted, concave BiVO4 polyhedron was fabricated, bounded by multiple high-index {012}, {210}, {115}, and {511} facets, exhibiting impressive photocatalytic O2 evolution for water oxidation in the absence of any cocatalysts, more than two orders of magnitude higher than that of the bulk materials. The corresponding apparent quantum yield (AQY) of O2 evolution was measured as high as 30.7% under 420 nm light irradiation, a new record AQY for BiVO4. The high-index facets are not only energetically favorable for water dissociation, but also exhibit an obvious reduction in the overpotential (0.7-1.0 V) for the oxygen evolution reaction.

We demonstrate for the first time an asymmetric squaraine-based low band-gap hole transporting material, which acted as both light harvesting and hole transporting layers in methylammonium lead triiodide perovskite solar cells. Opto-electrochemical characterization revealed extremely high molar extinction coefficients of the absorption bands in the low energy region and prominent space charge delocalization due to its electronically asymmetric nature. A suitable band alignment of the squaraine HOMO level with the valence band edge of the perovskite, and the conduction band of the TiO2 with LUMO of the perovskite allowed a cascade of hole extraction and electron injection, respectively. Red-shifted absorption was observed for both HTMs in thin films coated on the perovskite, and the optimized devices exhibited an impressive PCE of 14.7% under full sunlight illumination (100 mW cm(-2), AM1.5 G). The efficiency value is comparable to that of the devices using a state-of-the-art spiro-OMeTAD hole transport layer under similar conditions. Ambient stability after 300 h revealed that 88% of the initial efficiency remained for , and almost no change for , indicating that the devices had good long-term stability thus suggesting that the asymmetric squaraines have great potential as a dual-functional HTM for high performance perovskite solar cells.

2,2,7,7-tetrakis(N,N-dip-methoxyphenylamine)-9,9-spirobifluorene (spiro-OMeTAD) is a popular hole-transporting material (HTM) in perovskite solar cells (PSCs), However, it suffers from high-cost and stability issues, which need to be overcome for PSC commercialization. Here, we report isomers of bithiophene-based HTMs functionalized with triarylamine and imidazole for PSCs. The planar 3-ImBT-2D (1) exhibits higher hole mobility than 5-ImBT-2D (2) via modulation of donor-group positions. The PSCs using HTM (1) deliver an excellent power conversion efficiency (PCE) of 21.73% with Li-TFSI doping and 17.79% without dopants. In addition, the Li-TFSI-free device based on 3-ImBT-2D yields a PCE of 21% after HTM surface modification with organic p-dopant dimethylanilinium tetrakis(pentafluorophenyl)borate (DPB). A molecular dynamics study shows that the isomer 3-ImBT-2D (1) folds up after deposition on perovskite films. As a result, the Li-TFSI-free devices exhibit higher stability, retaining 95.9% of the initial PCE after 800 h aging.

The only significant factors in the study were the Pirani score and non-compliance of the brace with p < 0.05. There was not any significance in the correction of the deformity by Ponseti between idiopathic and non-idiopathic CTEV based on the number of casts and the Pirani score. The dynamic foot brace can be the solution for the high recurrence rate, yet more studies are needed in the future.

The remarkable significance of electrode materials in industrial processes, energy, sustainability and diabetes monitoring has captivated scientists to develop advance nanomaterials for the benefit of life across the globe. Here in, the recent developments in nanostructured porous metal and metal oxide composite materials for supercapacitor applications and non-enzymatic glucose sensors (NEGS) has been extensively discussed. The essential and active electrode materials from the research and application perspective has been emphasized in detail. We have also evaluated the worthiness, taxonomical classification, efficiency, specific capacitance and sensitivity of these materials for the aforementioned potential applications. Eventually, we concluded the review by providing the aspect ratio, surface morphology, particle size and specific surface area of these materials that plays an indispensable role for their promising potential applications.

Industrially, large-scale NH3 production is achieved by the Haber-Bosch process, which operates under harsh reaction conditions with abundant energy consumption and CO2 emission. Electrochemical N2 reduction is an eco-friendly and energy-saving method for artificial N2 to NH3 fixation under ambient reaction conditions. Herein, we demonstrate that ZrS2 nanofibers with a sulfur vacancy (ZrS2 NF-Vs) behave as an efficient electrocatalyst for ambient N2 reduction to NH3 with excellent selectivity. In 0.1 M HCl, this ZrS2 NF-Vs catalyst attains a large NH3 yield of 30.72 μg h-1 mgcat.-1 and a high faradaic efficiency of 10.33% at -0.35 V and -0.30 V vs. reversible hydrogen electrode, respectively. It also shows high electrochemical and structural stability. The density functional theory calculations reveal that the introduction of Vs facilitates the adsorption and activation of N2 molecules.

This work deals with first-principles and in silico studies of graphene oxide-based whole-cell selective aptamers for cancer diagnostics utilising a tunable-surface strategy. Herein, graphene oxide (GO) was constructed as a surface-based model with poly(N-isopropylacrylamide) (PNIPAM) covalently grafted as an "on/off"-switch in triggering interactions with the cancer-cell protein around its lower critical solution temperature. The atomic building blocks of the aptamer and the PNIPAM adsorbed onto the GO was investigated at the density functional theory (DFT) level. The presence of the monomer of PNIPAM stabilised the system's π-π interaction between GO and its nucleobases as confirmed by higher bandgap energy, satisfying the eigenvalues of the single-point energy observed rather than the nucleobase and the GO complex independently. The unaltered geometrical structures of the surface emphasise the physisorption type interaction between the nucleobase and the GO/NIPAM surface. The docking result for the aptamer and the protein, highlighted the behavior of the PNIPAM-graft-GO is exhibiting globular and extended conformations, further supported by molecular dynamics (MD) simulations. These studies enabled a better understanding of the thermal responsive behavior of the polymer-enhanced GO complex for whole-cell protein interactions through computational methods.

Designing of materials for the extraction of organic toxins are the critical factors for environmental remediation.

Abstract We report the synthesis of a novel nanocomposites based Poly(pyrrole‐co‐o‐toluidine) copolymer and cobalt ferrite (CoFe 2 O 4 ) as an electrochemical sensor for selective Pb 2+ detection. The general abbreviation of these new materials are given as P(Py‐co‐OT)/CF nanocomposites (P(Py‐co‐OT)/CF NCs). The synthesis was performed via in situ‐chemical oxidative polymerization method at different CoFe 2 O 4 weight ratio (5%, 10%, 30%, 50% and 70%), whereas CoFe 2 O 4 nanoparticle (NPs) was synthesized by an egg white method prior the nanocomposite formation. The structural, morphological, thermal, magnetic, electrical and electrochemical properties of pure P(Py‐co‐OT), CoFe 2 O 4 and P(Py‐co‐OT)/CF NCs were characterized by XRD, FTIR, TGA‐DTG, SEM‐EDX, TEM, VSM and electrical conductivity. The results of XRD and FTIR confirmed the formation of P(Py‐co‐OT)/CF NCs with the component CoFe 2 O 4 showing spinel structure. The analysis of TGA‐DTG presented that CoFe 2 O 4 NPs improved the thermal stability of NCs indicated the presence of some interactions between the interface of P(Py‐co‐OT) and CoFe 2 O 4 NPs, which affects the chemical and physical properties of the NCs. The ac conductivity was also examined as a function of temperature. The measures showed a decrease in the conductivity of NCs when increasing the insulating CoFe 2 O 4 NPs contents. A cost‐effective and reliable electrochemical sensor selective to Pb 2+ ion was fabricated using P(Py‐co‐OT)/CF NCs on glassy carbon (GCE). It was found that the P(Py‐co‐OT)/CF 10 NCs exhibit excellent detection of Pb 2+ ion. The proposed Pb 2+ ion sensor was performed linearly over the large concentration range of 0.1 nM ∼ 0.01 mM labelled as linear dynamic range (LDR). The sensitivity as well as detection limit were estimated to be 22.39 μAμM −1 cm −2 and 42.39 ±2.12 pM, respectively. The desired ionic sensor‐based on P(Py‐co‐OT)/CF 10 NCs/binder/GCE was found as efficient to detect Pb 2+ ion in environmental and biological samples significantly. The analytical sensor performances such as reproducibility, sensitivity, stability, validation, and response time were reliable and significant.