Direct-continuous preparation of nanostructured titania-silica using surfactant-free non-scaffold rice starch template

The conventional synthesis route of nanostructured titania-silica (Ti-SiNS) based on sol-gel requires the use of a surfactant-type template that suffers from hazardous risks, environmental concerns, and a tedious stepwise process. Alternatively, biomaterials have been introduced as an indirect template, but still required for pre-suspended scaffold structures, which hinder their practical application. Herein, we report an easy and industrially viable direct-continuous strategy for the preparation of Ti-SiNS from nanostructured-silica (SiNS) using a hydrolyzed rice starch template. This strategy fits into the conventional industrial process flow, as it allows starch to be used directly in time-effective and less complicated steps, with the potential to upscale. The formation of Ti-SiNS is mainly attributed to Ti attachment in the SiNS frameworks after the polycondensation of the sol-gel composition under acidic-media. The SiNS had pseudo-spherical morphology (nanoparticles with2·g the size of 13 to 22 nm), short order crystal structure (amorphous) and high surface area (538.74 m−1). The functionalized SiNS into Ti-SiNS delivered considerable catalytic activity for epoxidation of 1-naphtol into 1,4-naphthoquinone. The described direct-continuous preparation shows great promise for a cheap, green, and efficient synthesis of Ti-SiNS for advanced applications

Supramolecular design of benzene-1,3,5-tricarboxamide with hydrophobic alkyl side chains toward long-range liquid crystalline properties

Herein we report the first approach of benzene-1,3,5-tricarboxamides (BTAs) with long-range liquid crystalline properties by utilizing hydrophobic alkyl side chains at the amide functional group. These compounds were successfully prepared in high yields by reacting 1,3,5-benzenetricarbonyl trichloride with series of aliphatic linear alkyl amines as the side chains. By increasing the length of hydrocarbon chains at the amino, thermograms of BTAs showed the formation of mesophase rangesbetween 21.8- 196.3, 41.9 - 212.4, 57.9 - 203.7, 76.1 - 207.7 and 80.5 - 200.1 degrees for decylamine, dodecylamine, tetradecylamine, hexadecylamineand octadecylamine, respectively. Such liquid crystalline properties indicate the formation of self-assembly through supramolecular interactions with a lamellar structure. In particular, benzene tricarboxamide with short alkyl chains will reduce the Van der Waals interactions to give room temperature range of mesophase structure

Disclosure of nanomaterials under nanotechnology product inventory, voluntary certification, and voluntary labelling

Nanotechnology has revolutionised the food industry and flooded the consumers' market worldwide with engineered nanomaterials (ENMs), creating concerns on potential risks towards safety and health. This article analyses the institutional approach for disclosure of information on the presence of ENMs in food products and their limitations. It adopts a doctrinal approach and content analysis by examining relevant literature on disclosure of nanomaterials from journal articles and books from online databases and institutional websites. To overcome the limitations of the institutional approach of nanotechnology product inventories, voluntary certification programme, and voluntary labelling, this article proposes that the information disclosed must be in full and accurate. More importantly, the information on potential risks of exposure, use of nanotechnology, or presence of nanomaterials must be verified and constantly updated. This study hopes to significantly contribute to improving the transparency of nanofood information systems

Supramolecular interactions in aromatic structures for non-optical and optical chemosensors of explosive chemicals

The scientific investigation based on the molecular design of aromatic compounds for high-performance chemosensor is challenging. This is because their multiplex interactions at the molecular level should be precisely determined before the desired compounds can be successfully used as sensing materials. Herein, we report on the molecular design of chemosensors based on aromatic structures of benzene as the organic motif of benzene-1,3,5-tricarboxamides (BTA), as well as the benzene pyrazole complexes (BPz) side chain, respectively. In the case of BTA, the aromatic benzene acts as the centre to allow the formation of π–π stacking for one-dimensional materials having rod-like arrangements that are stabilized by threefold hydrogen bonding. We found that when nitrate was applied, the rod-like BTA spontaneously formed into a random aggregate due to the deformation of its hydrogen bonding to form inactive nitroso groups for non-optical sensing capability. For the optical chemosensor, the aromatic benzene is decorated as a side-chain of BPz to ensure that cage-shaped molecules make maximum use of their centre providing metal-metal interactions for fluorescence-based sensing materials. In particular, when exposed to benzene, CuBPz displayed a blue-shift of its original emission band from 616 to 572 nm (Δ = 44 nm) and emitted bright orange to green emission colours. We also observe a different mode of fluorescencebased sensing materials for Au-BPz, which shows a particular quenching mechanism resulting in 81% loss of its original intensity on benzene exposure to give less red-orange emission (λ = 612 nm). The BTA and BPz synthesized are promising high-performance supramolecular chemosensors based on the non-optical and optical sensing capability of a particular interest analyte

High-performance bimetallic catalysts for low-temperature carbon dioxide reforming of methane

Catalytic dry reforming of methane (DRM) is a promising way for renewable syngas production due to the utilization of both CO2 and CH4 greenhouse gases. Current approaches were made to improve the catalytic activity and coke resistance by introducing a second metal into the Ni-based catalytic system. This bimetallic catalytic system showed a significant improvement in coke resistance due to the synergistic effect of both metals towards the reaction. This review summarizes recent developments in bimetallic catalysts in DRM which focused on the evaluation of catalysts, deactivation studies, and reaction mechanisms of developed bimetallic catalysts

Impregnation of [Emim]Br ionic liquid as plasticizer in biopolymer electrolytes for EDLC application

A solid polymer electrolyte based on maltodextrin (MX) – methylcellulose (MC) – ammonium bromide (NH4Br) was successfully prepared via the solution casting method by impregnating different amounts of [Emim]Br. Interaction of the electrolyte components was proven by the Fourier transmission infrared (FTIR) and X-ray diffraction (XRD) analyses. With the addition of 30 wt% [Emim]Br (L30), the conductivity was enhanced to (3.39 ± 0.22) × 10-4 S cm-1 at room temperature. The L30 electrolyte achieved the lowest Ea value of 0.15 eV that obeyed the Arrhenius theory. Ionic conductivity was found to influence the ionic mobility (µ), number density (n) and diffusion coefficient (D), which was investigated using the EIS and FTIR methods. Dielectric analysis was further verified the conductivity trend and proved the non-Debye behavior. The electrolyte with 30 wt% [Emim]Br obtained the lowest Tg value of 68.91 °C. TGA/DTG results indicated that the electrolytes were thermally stable until ~ 400 °C. The ions were the main charge carriers based on the TNM result. LSV measurement revealed that the L30 electrolyte decomposed at 1.56 V. In the fabricated EDLC, specific capacitance values were measured using CV and charge–discharge analyses where the values obtained were 9.85 F g-1 and 9.47 F g-1, respectively. Energy and power densities were stabilized in the range of 0.1–0.2 Wh kg-1 and 20–25 W kg-1, respectively as the EDLC completed the cycles

Lamellar-structured fibrous silica as a new engineered catalyst for enhancing CO<inf>2</inf> methanation

Recently, Centre of Hydrogen Energy (CHE) has developed new structures of fibrous mesoporous silica nanoparticles (FMSN) and fibrous Mobil composition of matter-41 (FMCM-41) called CHE-SM and CHE-S41, respectively. Both are used as a support, along with adding 5 wt% Ni as active metal and examined on carbon dioxide (CO2) methanation. The low angle x-ray diffraction (XRD) and transmission electron microscopy (TEM) results proved that Ni/CHE-S41 possessed a hexagonal structure while Ni/CHE-SM was discovered in a lamellar structure. In addition, the XRD and N2 adsorption–desorption revealed that Ni particles were deposited on the surface of CHE-SM due to the smaller support pore size (4.41 nm) than the average Ni particles diameter (5.61 nm) resulting in higher basicity and reducibility. Meanwhile, Ni/CHE-S41 revealed deposition of Ni particles in the pore due to difference in support pore size (4.89 nm) compared to average Ni particles diameter (4.01 nm). Consequently, Ni/CHE-SM performed higher CO2 conversion (88.6 %) than Ni/CHE-S41 (82.9%) at 500 °C, while both achieved 100 % selectivity towards methane. Furthermore, the Ni/CHE-SM displayed excellent resistance towards coke formation during 50 h stability test at 500 °C. It is confirmed as Ni/CHE-SM exhibited a weight loss of 0.469% in TGA analysis and a G:D band ratio of 0.43 in Raman spectroscopy, both of which were lower than the corresponding values of Ni/CHE-S41 (0.596% weight loss and 0.74 G:D band ratio). These properties of Ni/CHE-SM are beneficial in methane production field as coke formation could affect the equilibrium of CO2 methanation process