Fabrication of high B-doped ordered mesoporous carbon with 4-hydroxyphenylborate phenolic resin for supercapacitor electrode materials

Functionalized cyanostilbene-based nano-AIEgens: multipoint binding interactions for improved sensing of gallic acid in real-life food samples

Cyano-substituted stilbene (CSS) derivatives have been synthesized that can form luminescent nanoscopic assemblies in an aqueous medium. The optical properties of such materials, as governed by the relative ratios of their monomer and aggregated forms, are found to be susceptible to pH and temperature of the medium. The compound with boronic acid attached at the terminal positions shows a turn-on fluorescence response (LOD: 15.4 ppb) with gallic acid (GA). The mechanistic studies indicate that the 1,2-diol unit of GA is involved in ester formation with the boronic acid residue, while the carboxylic end engages in hydrogen bonding interaction with the nitrile unit. Such multi-point binding interaction provides better selectivity over other structurally similar analytes. Moreover, the distinct aggregation properties of such boronate ester derivatives are responsible for the GA-specific optical response. The sensory system has been utilized for the determination of the levels of GA derivatives in tea (green tea and black tea) and various fruit (mango, orange, guava, pomegranate) extracts. In all cases, the estimated values of GAE were found to be in the same range reported by others. Finally, low-cost, chemically-modified paper strips have been designed for rapid, on-location detection of GA.

Efficient abatement of NOx emitted from automotive engines via adsorption on the Ba-CMK-3 adsorbents

The Ba-CMK-3(x) (x was the Ba(NO₃)₂:CMK-3 mass ratio and equals to 5, 10, and 15 wt%) samples were prepared by the incipient impregnation method, which were used for the adsorption of NO + O₂ at room temperature. The samples were characterized by the XRD, BET, TEM, TPD, TG, and DRIFTS techniques. The results showed that the CMK-3 and Ba-CMK-3(x) samples possessed an ordered two-dimensional hexagonal mesoporous structure, and Ba was uniformly dispersed on the surface of CMK-3. After Ba doping, the surface areas and pore size distributions of the Ba-CMK-3(x) samples were altered due to the synergistic effect of partial blocking of the channels by Ba and partial etching of the carbon materials by O₂ produced from Ba(NO₂)₃ decomposition at high temperatures. The sequence in NO adsorption capacity was Ba-CMK-3(10) (108.1 ± 0.55 mg/g) > Ba-CMK-3(15) (106.2 ± 0.72 mg/g) > Ba-CMK-3(5) (102.3 ± 1.33 mg/g) > CMK-3(88.8 ± 1.15 mg/g), with the Ba-CMK-3(10) sample showing the best (NO + O₂) adsorption performance. We proposed the two main adsorption pathways in the process of NO adsorption: (i) NO reacted with O₂ to form NO₂, part of NO₂ were weakly adsorbed on the surface hydroxyl groups, part of NO₂ were adsorbed to form the nitrite and nitrate species, and the left NO₂ was disproportionated to the NO, NO₂^-, and NO₃^- species; and (ii) NO was directly oxidized to the NO₂^- species by the oxygen-containing functional groups in carbon, and then some of the NO₂^- species were transformed to the NO₃^- species directly or via disproportionation. The regeneration efficiencies of the Ba-CMK-3(x) samples were slightly inferior to that of the CMK-3 sample.

Development of Boron-Doped Mesoporous Carbon Materials for Use in CO2 Capture and Electrochemical Generation of H2O2

Mesoporous carbon materials have been increasingly studied due to their large specific surface area and good chemical stability. Optimizing their functionality through a doping modification can broaden their application in many fields. Herein, a series of B-doped mesoporous carbon materials are prepared by a convenient hydrothermal synthesis using F127 as the template and boric acid as the boron source. The whole material preparation process meets the requirements of green chemistry. Notably, the prepared carbon materials not only exhibit good electrocatalytic oxygen reduction to hydrogen peroxide in alkaline media but also have an excellent CO2 adsorption capacity (up to 121.34 mg/g) at 303 K and atmospheric pressure. These results show that the prepared samples can be utilized as multifunctional materials for handling a variety of environmental issues.

Doping strategy, properties and application of heteroatom-doped ordered mesoporous carbon

To date, tremendous achievements have been made to produce ordered mesoporous carbon (OMC) with well-designed and controllable porous structure for catalysis, energy storage and conversion. However, OMC as electrode material suffers from poor hydrophilicity and weak electrical conductivity. Numerous attempts and much research interest have been devoted to dope different heteroatoms in OMC as the structure defects to enhance its performance, such as nitrogen, phosphorus, sulphur, boron, and multi heteroatoms. Unfortunately, the "how-why-what" question for the heteroatom-doped OMC has not been summarized in any published reports. Therefore, this review focuses on the functionalization strategies of heteroatoms in OMC and the corresponding process characteristics, including in situ method, post treatment method, and chemical vapor deposition. The fundamentally influencing mechanisms of various heteroatoms in electrochemical property and porous structure are summarized in detail. Furthermore, this review provides an updated summary about the applications of different heteroatom-doped OMC in supercapacitor, electrocatalysis, and ion battery during the last decade. Finally, the future challenges and research strategies for heteroatom-doped OMC are also proposed.

Synergistic impact of cellulose nanocrystals with multiple resins on thermal and mechanical behavior

The cellulose nanocrystals (CNCs) surface modified with phenolic and acrylic resins were investigated for different properties such as thermally stability and adhesive property, the mechanical properties of CNCs and interactions of the resulting materials at a micro-level are very important. Phenolic resins are of great interest due to their smooth structure, low thermal conductivity and good thermal insulation. However, the high spray rates and poor mechanical properties limit its use for external insulation of buildings. Acrylic resins are used as a matrix resin for adhesives and composites due to their adhesion, mechanical properties, and their good chemical resistance. The brittleness of acrylic resins makes them less attractive than the structural materials, being much harder. For this reason, most of the resins are modified with suitable elastomers, which act as hardeners. Therefore, treatment of these compounds is necessary. In this research paper, the effect of CNCs surface on phenolic and acrylic resins were investigated to obtain an optimized surface using three different weight (wt%) ratios of CNCs. Scanning electronic microscopy (SEM), X-rays diffraction (XRD), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the structure, and investigate different properties of CNCs. Furthermore, the Zwick/Roell Z020 model was used to investigate the adhesion properties of the phenolic and acrylic resins with CNCs.

Electrochemical performance of nano-sized LiFePO4-embedded 3D-cubic ordered mesoporous carbon and nitrogenous carbon composites

Herein, we report a single-step synthesis, characterization, and electrochemical performance of nano-sized LiFePO4 (LFP)-embedded 3D-cubic mesoporous carbon (CSI-809) and nitrogenous carbon (MNC-859) composites. Furthermore, in order to investigate the effects of both CSI-809 and MNC-859 on the electrochemical characteristics of LFP, a systematic study was performed on the morphology and microstructure of the composites, viz., LFP/CSI-809 and LFP/MNC-859, using XRD, FE-SEM, FT-Raman, and BET surface area analyses. Among these composites, LFP/MNC-859 exhibited better electrochemical performance with higher specific capacity and rate capability as compared to those of LFP/CSI-809. In addition, even after 100 cycles, LFP/MNC-859 retained 97% of its initial discharge capacity at 1C rate. The enhanced electrochemical performance of the nano-sized LFP-embedded MNC-859 can be attributed to the conductive nitrogenous carbon and mesoporosity, which facilitate electrolyte diffusion, and improved conductivity of the advanced LFP-nitrogenous porous carbon matrix.