Facile synthesis of copper nitroprusside chitosan nanocomposite and its catalytic reduction of environmentally hazardous azodyes

One of the biggest issues affecting the entire world currently is water contamination caused by textile industries' incapacity to properly dispose their wastewater. The presence of toxic textile dyes in the aquatic environment has attracted significant research interest due to their high environmental stability and their negative effects on human health and ecosystems. Therefore, it is crucial to convert the hazardous dyes such as methyl orange (MO) azo dye into environmentally safe products. In this context, we describe the use of Copper Nitroprusside Chitosan (Cu/SNP/Cts) nanocomposite as a nanocatalyst for the chemical reduction of azodyes by sodium borohydride (NaBH4). The Cu/SNP/Cts was readily obtained by chemical coprecipitation in a stoichiometric manner. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy were applied to investigate chemical, phase, composition, and molecular interactions. Additionally, Scanning electron microscope (SEM) was used to examine the nanomaterial's microstructure. UV-vis spectroscopy was utilized for studying the Cu Nitroprusside Chitosan's catalytic activity for the reduction of azodye. The Cu/SNP/Cts nanocomposite demonstrated outstanding performance with total reduction time 160 s and pseudo-first order constant of 0.0188 s-1. Additionally, the stability and reusability study demonstrated exceptional reusability up to 5 cycles with minimal activity loss. The developed Cu/SNP/Cts nanocomposite act as efficient nanocatalysts for the reduction of harmful Methyl orange azodye.

Rapid catalytic reduction of environmentally toxic azo dye pollutant by Prussian blue analogue nanocatalyst

The release of toxic azo dyes pollutants in the environment from different industries represents a public health concern and a serious environmental problem. Therefore, the conversion of hazardous methyl orange (MO) azo dye to environmentally benign products is a critical demand. In this work, an eco-friendly Prussian blue analogue (PBA) was synthesized and its catalytic activity toward the reduction of MO was investigated. The PBA copper(ii) hexacyanocobaltate(III) (Cu3[Co(CN)6]2) was synthesized by a facile inexpensive chemical coprecipitation method without using hazardous solvents. The nanocatalyst was characterized using XPS, Raman, FTIR spectroscopy, and XRD. The chemical reduction of MO using NaBH4 and the PBA as nanocatalyst was monitored by UV-VIS spectroscopy. Toxic MO was completely reduced in 105 s with a rate constant (k) 0.0386 s-1 using only 10 μg of the PBA nanocatalyst. Besides the powerful catalytic activity, the nanocatalyst also showed excellent stability and recyclability for ten consecutive cycles, with no significant decrease in the catalytic performance. Therefore, the proposed PBA is a promising, stable, cost-effective, and eco-friendly nanocatalyst for the rapid elimination of hazardous azo dyes.

Scalable Printing of Prussian Blue Analogue@Au Edge-Rich Microcubes as Flexible Biosensing Microchips Performing Ultrasensitive Sucrose Fermentation Monitoring

Sucrose is one of the most applied carbon sources in the fermentation process, and it directly determines the microbial metabolism with its concentration fluctuation. Meanwhile, sucrose also plays a key role of a protective agent in the production of biological vaccines, especially in the new mRNA vaccines for curing COVID-19. However, rapid and precise detection of sucrose is always desired but unrealized in industrial fermentation and synthetic biology research. In order to address the above issue, we proposed an ultrasensitive biosensor microchip achieving accurate sucrose recognition within only 12 s, relying on the construction of a Prussian blue analogue@Au edge-rich (PBA@AuER) microarchitecture. This special geometric structure was formed through exactly inducing the oriented PBA crystallization toward a certain plane to create more regular and continuous edge features. This composite was further transformed to a screen-printed ink to directly and large-scale fabricate an enzymatic biosensor microchip showing ultrahigh sensitivity, a wide detection range, and a low detection limit to the accurate sucrose recognition. As confirmed in a real alcohol fermentation reaction, the as-prepared microchip enabled us to accurately detect the sucrose and glucose concentrations with outstanding reusability (more than 300 times) during the whole process through proposing a novel analytical strategy for the binary mixture substrate system.

Electrospinning One-dimensional Surface-phosphorized CuCo/C nanofibers for Enzyme-free Glucose Sensing

Developing novel electrocatalysts is of great importance for the practical application of non-enzymatic glucose sensors. One-dimensional (1D) carbon fiber-supported copper-cobalt bimetallic electrocatalysts (CuCo-P350) are successfully prepared via electrospinning technology and...

Amperometric detection of antibiotic drug ciprofloxacin using cobalt-iron Prussian blue analogs capped on carbon nitride

Ciprofloxacin (CIP) electrochemical sensor was constructed using cobalt-iron Prussian blue analogs decorated on carbon nitride (Co-Fe-PBA@CN). Co-Fe-PBA decorated on CN was fabricated using a simple sonication-assisted hydrothermal method to prepare the composite to obtain a cube-shaped structure decorated on CN sheets. The fabricated Co-Fe-PBA@CN was physically characterized using XRD and SEM analysis. Then, the fabricated composite was electrochemically studied to sense antibiotic drug ciprofloxacin (CIP). The electrochemical behavior was investigated using tools such as cyclic voltammetry (CV) and amperometric I-t studies. The Co-Fe-PBA@CN modified electrode displays a wide linear range (0.005-300 and 325-741 μM) with a low detection limit (0.7389 and 1.0313 nM) and good sensitivity (0.3157 and 0.2263 μA.μM^-1cm^-2) toward CIP. The Co-Fe-PBA@CN modified electrode also exhibits good selectivity, reproducibility, and repeatability toward CIP. The proposed sensor was validated with real sample analysis, biological samples like urine and blood serum containing commercially available ciprofloxacin tablets were studied, and the results demonstrate good viability.

Improving generation of H2O2 and •OH at copper hexacyanocobaltate/graphene/ITO composite electrode for degradation of levofloxacin in photo-electro-Fenton process

In this work, copper hexacyanocobaltate was electro-deposited at amino-graphene-coated indium-tin-oxide glass to form multifunctional heterogeneous catalyst (CuCoG/ITO), which was confirmed by field emission scanning microscope, infrared spectra, X-ray diffraction, and electro-chemistry techniques. A novel heterogeneous photo-electro-Fenton-like system was established using CuCoG/ITO as an air-diffusion electrode, in which hydrogen peroxide (H₂O₂) and hydroxyl radical (•OH) could be simultaneously generated by air O₂ reduction. The productive rate of •OH could reached to 70.5 μmol h^-1 at - 0.8 V with 300 W visible light irradiation at pH 7.0, 0.1 M PBS. Levofloxacin could be quickly degraded at CuCoG/ITO during heterogeneous photo-electro-Fenton process in neutral media with a first-order kinetic constant of 0.49 h^-1.

Tin disulfide nanorod-graphene-β-cyclodextrin nanocomposites for sensing dopamine in rat brains and human blood serum

In the present work describes a facile synthesis of tin disulfide (SnS₂) nanorods decorated graphene-β-cyclodextrin (SnS₂/GR-β-CD) nanocomposite for robust and novel dopamine (DA) electrochemical biosensor applications. The DA biosensor was fabricated using the glassy carbon electrode (GCE) modified with SnS₂/GR-β-CD nanocomposite. The sonochemical and hydrothermal methods have been used for the synthesis of SnS₂/GR-β-CD. Different physicochemical methods were used to confirm the formation of the GR-β-CD, SnS₂, and SnS₂/GR-β-CD nanocomposite. The cyclicvoltammetric cathodic current response of DA was 5 folds higher than those observed at bare, β-CD, SnS₂-β-CD, and GR-β-CD modified GCEs. Under optimised conditions, the biosensor's DPV response current is linear to DA from the concentration of 0.01-150.76 μM. The detection limit of the biosensor was 4 nM. The SnS₂/GR-β-CD biosensor shows an excellent selectivity towards DA in the presence of common interfering species, including ascorbic acid and uric acid. Also, the as-prepared nanocomposite-modified electrode exhibited satisfactory long-term stability, sensitivity (2.49 μAμM^-1 cm^-2) along with reusability for detection of DA. The fabricated SnS₂/GR-β-CD biosensor was successfully used for the detection of DA in the rat brain and human blood serum samples.

Carbon supported olivine type phosphate framework: a promising electrocatalyst for sensitive detection of dopamine

In this study, a layered olivine-type LiMnPO₄/functionalized-multiwall carbon nanotube (f-MWCNTs) composite is used as an electrochemically active material for the real-time detection of dopamine. A wet-chemical ultrasonication process is used to combine LiMnPO₄ with f-MWCNTs at room temperature. The composite was subjected to various structural, morphological and electrochemical studies. The blending of olivine-type LiMnPO₄ into the f-MWCNTs is revealed by TEM analysis. The electrochemical activities of the LiMnPO₄/f-MWCNTs composite are systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) for the real-time detection of dopamine. Furthermore, the applicability of the as prepared LiMnPO₄/f-MWCNTs composite was extended for the detection of human serum (E48) and rat brain-serum (C7) samples with satisfactory recoveries for the real-time applications. All these studies revealed that the layered olivine-type LiMnPO₄/f-MWCNTs composite is a potential candidate in the field of electrochemical sensing.

In this study, layered olivine-type LiMnPO₄/functionalized-multiwall carbon nanotubes composite is used as an electrochemically active material for the real-time detection of dopamine and extended for the detection of human serum (E48) and rat brain-serum (C7) samples.

Trace level electrochemical determination of the neurotransmitter dopamine in biological samples based on iron oxide nanoparticle decorated graphene sheets

The trace level electrochemical determination of dopamine in biological samples based on an iron oxide nanoparticle-capped graphene sheet modified electrode.

Nano Metal-Organic Framework-Derived Inorganic Hybrid Nanomaterials: Synthetic Strategies and Applications

Nano- (or micro-scale) metal-organic frameworks (NMOFs), also known as coordination polymer particles (CPPs), have received much attention because of their structural diversities and tunable properties. Besides the direct use, NMOFs can be alternatively used as sacrificial templates/precursors for the preparation of a wide range of hybrid inorganic nanomaterials in straightforward and controllable manners. Distinct advantages of using NMOF templates are correlated to their structural and functional tailorability at molecular levels that is rarely acquired in any other conventional template/precursor. In addition, NMOF-derived inorganic nanomaterials with distinct chemical and physical properties are inferred to dramatically expand the scope of their utilization in many fields. In this review, we aim to provide readers with a comprehensive summary of recent progress in terms of synthetic approaches for the production of diverse inorganic hybrid nanostructures from as-synthesized NMOFs and their promising applications.

Modern Approach to the Synthesis of Ni(OH)2 Decorated Sulfur Doped Carbon Nanoparticles for the Nonenzymatic Glucose Sensor

As a growing aspect of materials science, there are an enormous number of synthesis routes that have been identified to produce materials, particularly through simple methodologies. In this way, the present study focuses on the easiest way to prepare sulfur doped carbon nanoparticles (SDCNs) using a flame synthesis method and has also demonstrated a novel route to synthesize Ni(OH)2 decorated SDCNs by a simple adsorption cum precipitation method. The SDCNs are alternative candidates to prestigious carbon materials such as graphene, carbon nanotubes, and fullerenes. Moreover, SDCNs provide excellent support to the Ni(2+) ion adsorption and initiate the formation of Ni(OH)2. The formation of Ni(OH)2 on the SDCN matrix was confirmed by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), selected area diffraction pattern (SAED), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). After these meticulous structural evaluations, we have described the mechanism for the formation of Ni(OH)2 on an SDCN matrix. The as-prepared Ni(OH)2 decorated SDCN nanocomposites were used as an electrode material for nonenzymatic glucose sensors. The fabricated glucose sensor exhibited a wide linear concentration range, 0.0001-5.22 mM and 5.22-10.22 mM, and a low-level detection limit of 28 nM. Additionally, it reveals excellent selectivity in the potentially interfering ions and also possesses a good stability. The practicality of the fabricated glucose sensor was also demonstrated toward glucose detection in biological samples.