MOF-Derived Cu@Cu2O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu2O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions

PdO/ZnO@mSiO2 Hybrid Nanocatalyst for Reduction of Nitroarenes

Development of a novel approach for synthesizing nanostructured catalysts and achieving further improvements in catalytic activity, effectiveness, and efficiency remains a major challenge. In this report, we describe the preparation of a nanostructured PdO/ZnO@mSiO2 hybrid nanocatalyst featuring well-dispersed PdO nanoparticles within hollow ZnO@mSiO2. The as-prepared PdO/ZnO@mSiO2 hybrid nanocatalyst exhibited good morphological features, derived from the controlled stepwise synthesis from Pd/PS@ZIF-8@mSiO2 (PS = polystyrene). The morphology, size, oxidation state, crystallinity, and thermal stability of the prepared PdO/ZnO@mSiO2 hybrid nanocatalyst were confirmed by a series of physicochemical techniques. The PdO/ZnO@mSiO2 hybrid nanocatalyst showed very high catalytic efficiency in the reduction of 4-nitrophenol and various nitroarenes under eco-friendly conditions. Therefore, the PdO/ZnO@mSiO2 hybrid nanocatalyst is a promising alternative catalyst for applications in environmental remediation

Design of Graphene- and Polyaniline-Containing Functional Polymer Hydrogel as a New Adsorbent for Removal of Chromium (VI) Ions

Hydrogels find applications in various fields, and the ever-growing spectrum of available monomers, crosslinking, and nanotechnologies widen the application of polymer hydrogels. Herein, we describe the preparation of a new graphene (G)- and polyaniline (PANI)-containing functional polymer gel (G/PANI/FG) through a facile crosslinking copolymerization approach. Several characterization techniques such as field-emission scanning electron microscopy, Fourier-transform infrared, and X-ray photoelectron spectroscopy were employed to understand the physicochemical characteristics of the G/PANI/FG. The new G/PANI/FG was used as an adsorbent for chromium (VI) and exhibited the highest Cr (VI) removal efficiency (~97%). The inclusion of G and PANI in the gel results in high surface area, 3D porous structure, and Cr (VI)-chelating amine sites, which enhanced the Cr (VI) removal efficiency and thermal stability of the gel adsorbent. The results of our study revealed that G/PANI/FG is suited for the removal of Cr (VI) from aqueous solution

Ultrasensitive detection of hydrogen peroxide and dopamine using copolymer-grafted metal-organic framework based electrochemical sensor

We reported the synthesis of a copolymer- and metal-organic framework-based electrochemical sensor, UiO-66-NH2@P(ANI-co-ANA) using the polymerization method for the highly sensitive and selective detection of hydrogen peroxide (H2O2) and dopamine (DA). The as-synthesized material was characterized via Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The electrochemical characteristics of the proposed sensor were evaluated via impedance spectroscopy and cyclic voltammetry (CV). The electrochemical oxidation of DA and the reduction of H2O2 were determined via CV, square-wave voltammetry, and chronoamperometric techniques. The fabricated sensor exhibited a wide linear range of 25-500 mu M, with a sensitivity of 1396.1 mu A mu M-1 cm(-2) and a limit of detection of 0.6 mM, for the electrochemical reduction of H2O2. Additionally, it exhibited a wide linear range of 10-110 mM, with a sensitivity of 1110.2 mu A mu M(-1)cm(-2) and a limit of detection of 0.3 mu M, for the electrochemical detection of DA. The practical utility of the fabricated sensor was evaluated via the detection of H2O2 in milk samples and DA in human urine samples. (C) 2020 Elsevier B.V. All rights reserved