A mesoporous silver-doped TiO2-SnO2 nanocomposite on g-C3N4 nanosheets and decorated with a hierarchical core-shell metal-organic framework for simultaneous voltammetric determination of ascorbic acid, dopamine and uric acid.

An electrochemical sensor is described for the simultaneous voltammetric determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). An indium-tin oxide (ITO) electrode was modified with a hierarchical core-shell metal-organic framework and Ag-doped mesoporous metal-oxide based hybrid nanocomposites on g-C3N4 nanosheets. The morphology, structural and chemical composition of the hybrid nanocomposite was characterized using different analytical methods. The modified ITO showed superior electrocatalytic performance towards the oxidation of AA, DA and UA due to the enhanced surface area, synergistic effects and well-organized porous assembly. Figures of merit, include (a) linear responses from 0.1 to 200 µM, 2.5 to 100 µM and 2.5 to 625 µM; (b) detection limits (at S/N = 3) of 0.02, 0.01 and 0.06 µM, and (c) well separated oxidation peaks near -50, 186 and 390 mV (vs. Ag/AgCl) for simultaneous sensing AA, DA and UA, respectively. The sensor was evaluated by analysing spiked serum samples and gave data with precision, with recoveries of >98%. Graphical abstractSchematic Representation of a Mesoporous Silver-doped TiO2-SnO2 Nanocomposite (h-ATS) on g-C3N4 Nanosheets and Decorated with a Hierarchical Core-Shell Metal-Organic Framework (NC@GC) Based Electrochemical Sensor for Simultaneous Voltammetric Detection of Ascorbic acid, Dopamine and Uric acid.

Physico-chemical processes.

The review scans research articles published in 2018 on physico-chemical processes for water and wastewater treatment. The paper includes eight sections, that is, membrane technology, granular filtration, flotation, adsorption, coagulation/flocculation, capacitive deionization, ion exchange, and oxidation. The membrane technology section further divides into six parts, including microfiltration, ultrafiltration, nanofiltration, reverse osmosis/forward osmosis, and membrane distillation. PRACTITIONER POINTS: Totally 266 articles on water and wastewater treatment have been scanned; The review is sectioned into 8 major parts;  Membrane technology has drawn the widest attention from the research community.

Platinum-Copper Bimetallic Alloy Nanoflowers as Efficient Electrocatalyst for the Methanol Oxidation Reaction.

Special morphological noble metal-based bimetallic alloy nanostructures became popular for methanol oxidation reaction in order to reduce the high cost of the Pt catalyst and improve the catalyst activity. Herein, we developed a facile one pot hydrothermal method for the synthesis of platinum-copper bimetallic nanoflowers (Pt-Cu NFs) in the presence of hexadecyl trimethyl ammonium bromide (CTAB). The morphology, structure and composition of Pt-Cu NFs were carefully characterized and the synthesized parameters were optimized systematically by adjusting different experimental conditions. Results showed that the CTAB usage and the NaI amount were critical to the controlled synthesis of Pt-Cu NFs. The Pt-Cu NFs were high-performance electrocatalysts for the methanol oxidation reaction (MOR) with superior activity and superior stability in alkaline solution, which were far better than pure Pt nanoparticle electrocatalysts.

CdS/ZnS Heterostructured Porous Composite with Enhanced Visible Light Photocatalysis.

Fabrication of semiconductor composites consisting of multicomponent or multiphase heterojunctions is a very effective strategy to design highly active photocatalyst systems. Here we present a facile design to fabricate novel CdS/ZnS heterostructured porous sheet-like nanocomposite based on a cation-exchanged hydrothermal procedure. Micro-structural analyses reveal that the product is a kind of heterostructured composite with porous structure and high crystallinity. The composite nanosheets exhibited enhanced visible-light photoactivity compared with pure ZnS or CdS. Among them, sample of Cd0.45Zn0.55S gave the highest degradation rate of about 99% under visible-light irradiation within 60 min when 10 mg of the sample was added into 50 mL of methyl orange in aqueous solution (10 mg/L). The enhanced photocatalytic activity was presumed to result from the direct photoinduced interfacial charge transfer (IFCT) from the valence band (VB) of ZnS to CdS.