RESUMEN
The reuse of waste biomass resources had become a hot topic in the sustainable development of human society. Biomass was an ideal precursor for preparing porous carbon. However, due to the complexity of biomass composition and microstructure, the quality reproducibility of biomass porous carbon was poor. Therefore, it was of great significance to develop a reliable method for preparing porous carbon from biomass. In this paper, The activated hydrothermal porous carbon was prepared by a combination of hydrothermal carbonization treatment and KHCO3 mild activation. The hydrothermal carbonization treatment could complete the morphology adjustment and iron doping of the carbon in one step, and the mild activation of KHCO3 could activate the porous carbon while maintaining the spherical morphology. Fe-modified porous carbon with carbon ball/nanosheet structure which facilitated ion/electrolyte diffusion and increased accessibility between surface area and electrolyte ions. Therefore, bagasse derived activated porous carbon had good specific capacitance (315.2 F/g at 1 A/g) and good cycle stability, with a capacitance loss of only 5.8% after 5000 charge-discharge cycles. This study showed that the combination of hydrothermal treatment and mild activation provided an effective way for the conversion of waste biomass into high-performance electrode materials.
RESUMEN
NHC-mediated deoxygenation of alcohols under photocatalytic conditions is described. The process provides various alkyl radicals, which can react with 1-bromoalkyne via Csp3-Csp coupling to afford internal alkynes in moderate to good yields. The method offers a new and convenient approach to synthesize internal alkynes.
RESUMEN
Highly ordered TiO2 nanotube arrays (TNTAs) have received great attention owing to their high surface area, stability and direct transport pathways. The TNTAs, modified with other materials exhibiting enhanced conductivity and capacitance have been considered to be promising anode materials for supercapacitors. In this work, MoO3/carbon@different crystallography-oriented TiO2 nanotube arrays (CTNTAs) were synthesized by an anodizing method and electrochemical deposition. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was tested by cyclic voltammogram (CV) and galvanostatic charge-discharge (GDC) tests. The results indicated that MoO3/carbon@(004) preferentially oriented TiO2 nanotube array electrodes have the advantages of combining p-TNTAs and MoO3 nanoparticles and exhibit high electrochemical performance and cycling stability. The highest specific capacitance of the MoO3-p-CTNTA electrode achieved is 194 F g-1 at a current density of 1 A g-1.
RESUMEN
A newly self-supported electrode composed of Mn3O4 on Ni foam/graphene (NF/graphene/Mn3O4) was synthesized in situ by electrodeposition, and was used as a supercapacitor electrode for the first time. An ultrahigh specific capacitance of 630â¯Fg-1 can be achieved at a current density of 0.5â¯Ag-1. The maximum energy density of 94.4â¯Whâ¯kg-1 can be achieved, and the capacitance retention can be maintained about 97% after 20,000 cycles at 10â¯Ag-1. The electrochemical properties, including specific capacitance, energy density and cycling performance, were better than those in previous reports on Mn3O4-graphene electrodes. Such an outstanding property may be attributed to its unique characteristics, such as self-supported structure, favorable electric conductivity and cellular-like porous morphology.
