Catalytic Reductive Degradation of Methyl Orange Using Air Resilient Copper Nanostructures

The study describes the application of oxidation resistant copper nanostructures as an efficient heterogeneous catalyst for the treatment of organic dye containing waste waters. Copper nanostructures were synthesized in an aqueous environment using modified surfactant assisted chemical reduction route. The synthesized nanostructures have been characterized by UV-Vis, Fourier transform infrared spectroscopy FTIR spectroscopy, Atomic force microscopy (AFM), Scanning Electron Microscopy (SEM), and X-ray diffractometry (XRD). These surfactant capped Cu nanostructures have been used as a heterogeneous catalyst for the comparative reductive degradation of methyl orange (MO) in the presence of sodium borohydride (NaBH4) used as a potential reductant. Copper nanoparticles (Cu NPs) were found to be more efficient compared to copper nanorods (Cu NRds) with the degradation reaction obeying pseudofirst order reaction kinetics. Shape dependent catalytic efficiency was further evaluated from activation energy (EA) of reductive degradation reaction. The more efficient Cu NPs were further employed for reductive degradation of real waste water samples containing dyes collected from the drain of different local textile industries situated in Hyderabad region, Pakistan

Highly sensitive electrochemical determination of captopril using CuO modified ITO electrode: the effect of in situ grown nanostructures over signal sensitivity

The study describes a new approach for the direct electro-oxidation of captopril (CAP) drug using a CuO modified ITO electrode. The modified ITO electrode consists of an in situ grown film which accommodates dense CuO nanostructures with morphological features similar to flowers. The in situ growth over the ITO substrate was achieved using a simple hydrothermal route with the assistance of malonic acid which acted as an effective growth template. The devised electrode was evaluated in reference to its slurry-derived counterpart which involved surface modification of GCE using a conventional approach (drop-casting). The competitive evaluation of the discussed electrodes against the electro-oxidation of CAP, provided significant evidence to support the importance of controlled nanostructure distribution over the electrode surface to achieve higher signal sensitivity and reproducibility. The devised ITO/CuO electrode was known to possess excellent sensing capability against CAP within the linear working range of 0.01 to 3.43 mu M with signal sensitivity down to 2 x 10(-3) mM. Moreover, the ITO/CuO was noted to exhibit high charge transfer co-efficient (a), diffusion coefficient (D) and rate constant values of 0.83, 9.28 x 10(-5) cm(2) s(-1) and 3.5 x 10(3) mol(-1) L s(-1) respectively. In addition, the successful usage of ITO/CuO for CAP determination from commercial tablets and human urine samples further indicated the practical workability of the proposed electrode system

Sensitive Determination of 6-Thioguanine Using Caffeic Acid-functionalized Fe3O4 Nanoparticles as an Electrochemical Sensor

The study demonstrates the potential application of caffeic acid-functionalized magnetite nanoparticles (CA-Fe3O4 NPs) as an effective electrode modifying material for the electrochemical oxidation of the 6-thioguanine (6-TG) drug. The functionalized Fe3O4 NPs were prepared using simple wet-chemical methodology where the used caffeic acid acted simultaneously as growth controlling and functionalizing agent. The study discusses the influence of an effective functionalization on the signal sensitivity observed for the electro-oxidation of 6-TG over CA-Fe3O4 NPs in comparison to a glassy carbon electrode modified with bare and nicotinic acid (NA)-functionalized Fe3O4 NPs. The experiment results provided sufficient evidence to support the importance of favorable functionality to achieve higher signal sensitivity for the electro-oxidation of 6-TG. The presence of favorable interactions between the active functional moieties of caffeic acid and 6-TG synergized with the greater surface area of magnetic NPs produces a stable electro-oxidation signal within the working range of 0.01-0.23 mu M with sensitive up to 0.001 mu M. Additionally, the sensor showed the strong anti-interference potential against the common co-existing drug molecules such as benzoic acid, acetaminophen, epinephrine, norepinephrine, glucose, ascorbic acid and l-cysteine. In addition, the successful quantification of 6-TG from the commercial tablets obtained from local pharmacy further signified the practical capability of the discussed sensor

In Situ Growth of CuWO4 Nanospheres over Graphene Oxide for Photoelectrochemical (PEC) Immunosensing of Clinical Biomarker

Procalcitonin (PCT) protein has recently been identified as a clinical marker for bacterial infections based on its better sepsis sensitivity. Thus, an increased level of PCT could be linked with disease diagnosis and therapeutics. In this study, we describe the construction of the photoelectrochemical (PEC) PCT immunosensing platform based on it situ grown photo-active CuWO4 nanospheres over reduced graphene oxide layers (CuWO4@rGO). The in situ growth strategy enabled the formation of small nanospheres (diameter of 200 nm), primarily composed of tiny self-assembled CuWO4 nanoparticles (2-5 nm). The synergic coupling of CuWO4 with rGO layers constructed an excellent photo-active heterojunction for photoelectrochemical (PEC) sensing. The platform was then considered for electrocatalytic (EC) mechanism-based detection of PCT, where inhibition of the photocatalytic oxidation signal of ascorbic acid (AA), subsequent to the antibody-antigen interaction, was recorded as the primary signal response. This inhibition detection approach enabled sensitive detection of PCT in a concentration range of 10 pgmL(-1) to 50 ng.mL(-1) with signal sensitivity achievable up to 0.15 pgmL(-1). The proposed PEC hybrid (CuWO4@rGO) could further be engineered to detect other clinically important species.Funding Agencies|National Natural Science Foundation of China (NSFC)National Natural Science Foundation of China [51572011, 51802012]</p

Tartaric acid assisted in-situ growth of CuO nanostructures over ITO substrate for the electrocatalytic detection of Sudan I

The study explores the potential of newly developed ITO based electrode for the electro-catalytic detection of Sudan I. The ITO based electrode utilizes a dense layer of 2D CuO nanostructures as an effective electron-transfer facilitator which promotes the electro-catalytic sensing of Sudan I in aqueous solution. The in-situ growth of CuO nanostructures was achieved using simple hydrothermal route with the assistance of tartaric acid utilized as an effective template. The in-situ grown layer comprises of 2D CuO nanostructures with morphological features similar to flowers composed of sharp-flake like features. The electro-catalytic oxidation of Sudan I over the described electrode system demonstrated low-over potential value and excellent working stability with good analytical linearity in the range of 0.001-1.56 mu M. The ITO based electrode was found highly selective and sensitive towards Sudan I with limit of detection determined to be 1.2 x 10(-4) mu M (S/N = 3)