Large-Scale Synthesis of Reduced Graphene Oxides with Uniformly Coated Polyaniline for Supercapacitor Applications

We report an effective route for the preparation of layered reduced graphene oxide (rGO) with uniformly coated polyaniline (PANI) layers. These nanocomposites are synthesized by chemical oxidative polymerization of aniline monomer in the presence of layered rGO. SEM, TEM, X-ray photoelectron spectroscopy (XPS), FTIR, and Raman spectroscopy analysis results demonstrated that reduced graphene oxide-polyaniline (rGO-PANI) nanocomposites are successfully synthesized. Because of synergistic effects, rGO-PANI nanocomposites prepared by this approach exhibit excellent capacitive performance with a high specific capacitance of 286Fg(-1) and high cycle reversibility of 94% after 2000cycles

ZIF-8 derived, nitrogen-doped porous electrodes of carbon polyhedron particles for high-performance electrosorption of salt ions

Three-dimensional (3-D) ZIF-8 derived carbon polyhedrons with high nitrogen (N) content, (denoted as NC-800) are synthesized for their application as high-performance electrodes in electrosorption of salt ions. The results showed a high specific capacitance of 160.8 F·g−1 in 1 M NaCl at a scan rate of 5 mV·s−1. Notably, integration of 3-D mesopores and micropores in NC-800 achieves an excellent capacitive deionization (CDI) performance. The electrosorption of salt ions at the electrical double layer is enhanced by N-doping at the edges of a hexagonal lattice of NC-800. As evidenced, when the initial NaCl solution concentration is 1 mM, the resultant NC-800 exhibits a remarkable CDI potential with a promising salt electrosorption capacity of 8.52 mg·g−1

Mental health status of health care professionals working in public and private sectors in Visakhapatnam: A cross-section study

Introduction: The material that is currently available on the psychological issues that doctors deal with is restricted to a few national surveys and certain particular hospital surveys. The motive of the current study was to define the mental health status of medical as well as surgical professionals working in the public and private sectors of Visakhapatnam, Andhra Pradesh, India. Methodology: A self-reported questionnaire survey was used in an observational cross-sectional study to appraise the mental health state of both private and public medical practitioners. The Kessler Psychological Distress Scale (K10) by William C. Menninger was applied. Results: The majority of study participants experienced psychological anguish, showing a substantial difference in the total level of psychological distress. When the Wellinger's Distress and the Kesslers Distress tools were compared, it was found that there was a substantial difference for all the variables taken into account in the current study, including gender, experience, marital status, children, and occupation, designation, and sector of work. Conclusion: Stress and burnout were more prevalent among medical specialists with lower yearly income, young ages, and fewer years of practice. Clinicians and policymakers must be proactive in creating programes that help healthcare professionals cope with stress and burnout

Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs)

We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (eta) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320 nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (V-OC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs

Three-dimensional macroporous graphitic carbon for supercapacitor application

Two-dimensional (2D) graphene materials have attracted great interest as promising electrode materials in supercapacitors due to their high electrical conductivity derived from sp(2)-cabon network. These 2D layered materials, however, tend to stack with each other, which largely decreases the surface area. Here we report the design of highly graphitic macroporous carbon with large surface area suitable for supercapacitor applications. When benchmarked with other carbon materials, such as amorphous macroporous carbon, activated carbon, graphite or exfoliated graphene oxides, our graphitic macroporous carbon show superior capacitance

Synthesis of MOF-525 derived nanoporous carbons with different particle sizes for supercapacitor application

Nanoporous carbon (NC) materials have attracted great research interest for supercapacitor applications, because of their excellent electrochemical and mechanical stability, good electrical conductivity, and high surface area. Although there are many reports on metal-organic framework (MOF)-derived carbon materials, previous synthetic studies have been hindered by imperfect control of particle sizes and shapes. Here, we show precise control of the particle sizes of MOF-525 from 100 nm to 750 nm. After conversion of MOF-525 to NC, the effects of variation of the particle size on the electrochemical performance have been carefully investigated. The results demonstrate that our NC is a potential candidate for practical supercapacitor applications

Synthesis of MOF-525 derived nanoporous carbons with different particle sizes for supercapacitor application

Nanoporous carbon (NC) materials have attracted great research interest for supercapacitor applications, because of their excellent electrochemical and mechanical stability, good electrical conductivity, and high surface area. Although there are many reports on metal-organic framework (MOF)-derived carbon materials, previous synthetic studies have been hindered by imperfect control of particle sizes and shapes. Here, we show precise control of the particle sizes of MOF-525 from 100 nm to 750 nm. After conversion of MOF-525 to NC, the effects of variation of the particle size on the electrochemical performance have been carefully investigated. The results demonstrate that our NC is a potential candidate for practical supercapacitor applications

Significant effect of pore sizes on energy storage in nanoporous carbon supercapacitors

Mesoporous carbon can be synthesized with good control of surface area, pore-size distribution, and porous architecture. Although the relationship between porosity and supercapacitor performance is well known, there are no thorough reports that compare the performance of numerous types of carbon samples side by side. In this manuscript, we describe the performance of 13 porous carbon samples in supercapacitor devices. We suggest that there is a "critical pore size" at which guest molecules can pass through the pores effectively. In this context, the specific surface area (SSA) and pore-size distribution (PSD) are used to show the point at which the pore size crosses the threshold of critical size. These measurements provide a guide for the development of new kinds of carbon materials for supercapacitor devices

Effects of structural crystallinity and defects in microporous Al-MOF filled chitosan mixed matrix membranes for pervaporation of water/ethanol mixtures

A new two-dimensional microporous metal organic framework (MOP), Al-MOF, [Al(OH)(MBA)] (CYCU-7, MBA = diphenylmethane-4,4'-dicarboxylate anion) and its reported analogue, [Al(OH)(SBA)] (CAU-11, SBA = 4,4'-sulfonyldibenzoate anion), have been synthesized using hydrothermal and solvothermal methods, respectively, and their structural crystallinities and defect porosities were carefully controlled and characterized by N-2 sorption isotherms and Al-27 solid-state nuclear magnetic resonance measurements. Interestingly, the MOF synthesized by the ethanol-based solvothermal method (CYCU-7) show a significant degree of linker-missing defects compared to that synthesized by the water-based hydrothermal method (CAU-11). We further incorporated the synthesized CYCU-7 and CAU-11 with chitosan (CS) biopolymer to make CYCU-7@CS and CAU-11@CS mixed matrix membranes (MMMs) with the loading amount of MOF 2.5, 5.0, or 10 wt%. The as-prepared CYCU-7@CS and CAU-11@CS MMMs were applied for separation of water/ethanol mixtures through the pervaporation process, and the effects of the structural properties (e.g. crystallinity and defects) of CYCU-7 and CAU-11 on the separation performance are studied. It is found that defect-rich CYCU-7@CS MMMs exhibit higher flux, while CAU-11@CS MMMs with higher crystallinity exhibit a higher separation factor. In addition, the CAU-11@CS MMM with 5.0 wt% loading of CAU-11 displays the best separation performance (separation factor = 2741 and flux = 458 g/m(2) h). (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved