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[en] A suitable control of the reaction conditions to govern polymer qualities requires a deep understanding of topics such as polymer chemistry, standard thermodynamics, reaction kinetics, colloid science and reaction engineering. Good and reliable models represent a fundamental tool for the solution of this problem. In order to explain the potentials of models, in this paper some significant aspects concerning emulsion polymerization and catalytic Ziegler-Natta polymerization will be illustrated
[en] It is highly challenging to explore high–performance bi-functional oxygen electrode catalysts for their practical application in next-generation energy storage and conversion devices. In this work, we synthesize hierarchical N–doped carbon microspheres with porous yolk–shell structure (NCYS) as a metal-free electrocatalyst toward efficient oxygen reduction through a template-free route. The enhanced oxygen reduction performances in both alkaline and acid media profit well from the porous yolk–shell structure as well as abundant nitrogen functional groups. Furthermore, such yolk–shell microspheres can be used as precursor materials to motivate the oxygen reduction activity of oxygen evolution oriented materials to obtain a desirable bi-functional electrocatalyst. To verify its practical utility, Zn–air battery tests are conducted and exhibit satisfactory performance, indicating that this constructed concept for preparation of bi-functional catalyst will afford a promising strategy for exploring novel metal–air battery electrocatalysts. (paper)
[en] Highlights: • Phosphorus-doped graphene (P-RGO) was facilely fabricated by a hydrothermal reduction approach. • An effective electrochemical sensor for acetaminophen was developed based on P-RGO materials. • The sensor exhibited enhanced sensitivity, excellent anti-interference ability, reproducibility, and stability. • Satisfying recovery results for acetaminophen detection in real Pharmaceutical tablet samples were achieved. - Abstract: Phosphorus-doped graphene (P-RGO) was synthesized and employed as active electrode material to construct electrochemical sensor for acetaminophen (AP). The P-RGO coated glass carbon electrode (P-RGO/GCE) showed an excellent electrocatalytic activity for the oxidation of AP, resulted from highly enhanced electrochemical conductivity and accelerated electron transfer. The experimental conditions for AP detection were optimized, and under the optimal condition, a linear relationship between current intensity and concentration of AP was obtained in the range of 1.5–120 µM with a detection limit of 0.36 µM (S/N = 3). The developed sensor showed high selectivity for AP in the presence of various common species, excellent reproducibility and stability. The present sensor was also successfully applied for AP detection in pharmaceutical tablet samples.
[en] Highlights: • A high mass-transport bioelectrocatalytic interfaces based on a nanoparticle-polymer framework is investigated. • The compatibility of bio- anode and cathode was tested with electrochemical methods. • The bioelectrodes can offer highly efficient membrane-less bioenergy devices. • The biofuel cell delivers a high-power density and open circuit voltage compared to conventional polymer-based biofuel cells. • The nanoparticle-polymer framework could significantly accelerate developments in the field of high-performance bio-energy devices. Bioenergy based devices are rapidly gaining significant research interest because of growing quest for future alternative energy resources, but most of the existing technologies suffer from poor electron transfer and slow mass transport, which hinder the fabrication of realistic high-power devices. Using a versatile strategy, here we have demonstrated the fabrication of nanoparticle-polymer framework based bioelectrocatalytic interfaces which facilitate a high mass-transport and thus offers the simple construction of advanced enzyme-based biofuel cells. It has been shown that a gold nanoparticle-structured polyaniline network can be effectively used as an electrical cabling interface providing efficient electron transfer for bio- anode and cathode. The resulting bioelectrodes are capable of excellent diffusional mass-transport and thus can easily facilitate the design of new and highly efficient membrane-less advanced bioenergy devices. The biofuel cell delivers a high-power density of about 2.5 times (i.e., 685 µW cm−2) and open circuit voltage of 760 mV compared to conventional conducting polymer-based biofuel cells.
[en] Bosk-like Co–Sn–Se monocrystals are deposited on porous Ti plate through a hydrothermal method. The prepared Co–Sn–Se was characterized with morphology, composition and electrocatalytic properties. Electrochemical measurements revealed that the Ti/Co–Sn–Se electrodes exhibited great catalytic performance for hydrogen evolution reaction with the low onset overpotential of − 50 mV, the small Tafel slope of 83 mV/dec and good stability over an extended period of 34,000 s. The high electrocatalytic activity of bosk-like Co–Sn–Se monocrystals, the fast electron transfer between electrodes and catalysts, and the high conductivity of Ti contribute to their acceptable electrocatalytic performance.
[en] We have developed efficient nanostructures of Cu–Co–Ni alloy with varied stoichiometry as an alternative to the costly Pt-based alloys for hydrogen evolution reaction (HER). These nanoparticles were synthesized using the reverse micellar method. The size of the alloy nanoparticles varied from 40 to 70 nm. An enhanced catalytic activity as evident from high current density was observed for these Cu–Co–Ni (111) alloys which follows the Volmer–Heyrovsky mechanism. They have excellent stability (up to 500 cycles) and significant activity in acid media which might be due to the low hydrogen binding energy. (paper)
[en] Synthesis of nanomaterials have become the focus of intensive research due to their numerous applications in diverse fields such as electronics, optics, ceramics, metallurgy, pulp and paper, environmental, pharmaceutics, biotechnology and biomedical fields. Due to expanding demand for the nanomaterials with defined properties, extensive research activities have been focused on the synthesis and characterization of “functional nanomaterials”. Our research group launched into research activities on the preparation of varieties of functional materials using radiation as the source for inducing functionalities ino these new nanomaterials. Importantly, we kept final goals for specific applications. Thus, we have prepared few interesting functional nanomaterials such as metal nanoparticles decorated multi wall carbon nanotubes, pore filled functional electrospun nanofibers and nanocables based on conducting polymer and carbon nanotubes and demonstrated their applications toward electrocatalysts, polymer electrolyte in energy devices and biosensors. In the forthcoming sections, a brief outline on the use of radiation for the preparation of those functional nanomaterials are presented. (author)
[en] Graphene is a flat monolayer of sp2 bonded carbon atoms tightly packed into a two-dimensional honeycomb lattice. Graphene sheets have attracted great attention for both fundamental science and applied research due to their high specific surface area, high conductivity, superior optics and mechanical properties. Graphene oxide (GO) is one of the most common precursors for the preparation of graphene. The presence of oxygen-containing functional groups in GO makes it hydrophilic and thus it can be easily dispersed into aqueous solutions. Electrochemical reduction of GO is the reagent free process to prepare graphene, which will henceforth be called as reduced graphene oxide (rGO). In the present study, the aqueous dispersion of GO was drop-casted on glassy carbon (GC) electrode under optimized conditions. Then it was electrochemically reduced in saturated sodium carbonate (Na2CO3) solution. The electron transfer reaction of U(VI)/U(V) redox couple was investigated at rGO in saturated Na2CO3 solution
[en] Highlights: • A highly sensitive and selective electrochemical sensor was developed. • Conditions were optimized for the trace level detection of Cd2+ and Hg2+. • The sensor was found to rapidly sense nanomolar concentration of the target analytes. • High anti-interference ability suggested the practical applicability of the designed sensor. - Abstract: In the present work we report the development of a novel electrochemical sensor associated with high sensitivity, selectivity, cost affordability and fast sensing ability. We used 1-phenyl-N-(pyridin-2-ylmethyl)ethanamine (PPE) as a recognition layer over the surface of glassy carbon electrode for the trace level detection of mercuric (Hg2+) and cadmium (Cd2+) ions. The effects of pH, temperature, concentration of the modifier, accumulation time, deposition potential and supporting electrolytes were examined to optimize conditions for achieving the best sensing response of the analytes. The designed sensors demonstrated good percentage recovery, remarkable electrocatalytic activity and excellent discrimination ability for the target analytes in the presence of interfering metal ions. The wide linearity range and quite lower detection limits of 0.1 nM and 0.8 nM for Hg+2 and Cd+2 ions suggested the promising candidature of the designed sensor for monitoring heavy metal ions in aqueous systems.