The Efficient Recyclable Molybdenum- and Tungsten-Promoted Mesoporous ZrO2 Catalysts for Aminolysis of Epoxides

In the present study, we report the synthesis and catalytic activity of tungsten- and molybdenum-promoted mesoporous metal oxides in the aminolysis of epoxides. The as-synthesized catalysts were fully characterized by a variety of techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), temperature-programmed reduction (TPR) and desorption (TPD), nitrogen sorption measurements, powder X-ray diffraction (p-XRD), and thermogravimetric analysis (TGA). Amongst the two supports utilized, ZrO2 is a better support compared to SiO2. Furthermore, MoO3 proved to be a better dopant compared to its counterpart. Several parameters such as the variation of solvents, substrates, catalyst amounts, and stirring speed were investigated. It was observed that 450 rpm was the optimum stirring speed, with toluene as the best solvent and styrene oxide as the best substrate. Moreover, the optimum parameters afforded 98% conversion with 95% selectivity towards 2-phenyl-2-(phenylamino) ethanol and 5% towards 1-phenyl-2-(phenylamino) ethanol. Furthermore, 5%MoO3-ZrO2 catalyst demonstrated optimal performance and it exhibited excellent activity as well as great stability after being recycled 6 times.

Ultrafast Crystallization of Ordered Mesoporous Metal Oxides and Carbon in Seconds

This Communication describes a facile strategy coupling block copolymer-directed self-assembly with high-power Joule heating to form highly crystalline and long-range ordered mesoporous oxide and carbon nanostructures in just a few seconds. The combined approach is compatible with various self-assembled hybrid systems, generating mesoporous composites of γ-Al2O3-carbon, γ-Al2O3/MgO-carbon and anatase-TiO2-carbon with p6mm symmetry, as well as mesoporous non-close-packed carbon structures. Removing the polymer/carbon gives well-defined mesoporous all-γ-Al2O3 and all-anatase-TiO2 structures. Impregnation of chloroplatinic acid followed by Joule heating yields platinum nanoparticles decorated on the channel walls of mesoporous γ-Al2O3-carbon structures. The rapid formation of thermally stable and periodically ordered crystalline oxide, carbon and oxide-carbon structures. <br>

Ultrafast Crystallization of Ordered Mesoporous Metal Oxides and Carbon in Seconds

This Communication describes a facile strategy coupling block copolymer-directed self-assembly with high-power Joule heating to form highly crystalline and long-range ordered mesoporous oxide and carbon nanostructures in just a few seconds. The combined approach is compatible with various self-assembled hybrid systems, generating mesoporous composites of γ-Al2O3-carbon, γ-Al2O3/MgO-carbon and anatase-TiO2-carbon with p6mm symmetry, as well as mesoporous non-close-packed carbon structures. Removing the polymer/carbon gives well-defined mesoporous all-γ-Al2O3 and all-anatase-TiO2 structures. Impregnation of chloroplatinic acid followed by Joule heating yields platinum nanoparticles decorated on the channel walls of mesoporous γ-Al2O3-carbon structures. The rapid formation of thermally stable and periodically ordered crystalline oxide, carbon and oxide-carbon structures. <br>

TiO2 Nanofibers Decorated with Monodispersed WO3 Heterostruture Sensors for High Gas Sensing Performance Towards H2 Gas

A simple spin coating method was used to prepare the WO3-TiO2 heterostructural nanofibers (HNFs). Various kinds of techniques, including XRD, SEM, TEM, EDS and XPS, have described the structures, chemical constitutions and morphologies of the samples. Following the decoration of the WO3 nanocubes on the surface of TiO2 nanofibers, XPS findings confirmed the presence of W5+ and the excess proportion of both chemisorbed reactive oxygen and oxygen vacancies. WO3 incorporated TiO2 thin film sensor showed high sensing response (78%), rapid response (20 s) and recovery time (23 s) with respect to other gas molecules (NH3, NO2, LPG and SO2). The finding demonstrates that the WO3-TiO2 sensor showed good selective response towards H2 gas. A unique path was created by this work to build hetero-highly ordered mesoporous metal oxides junctions for applications in H2 gas sensor based devices.

Recent advances in mechanochemical synthesis of mesoporous metal oxides

There is a growing interest in mesoporous metal oxides due to their unique properties such as highly accessible porosity, stability, catalytic activity and diversity of nanostructures. Mechanochemical fabrication of mesoporous...

Ordered mesoporous metal oxides for electrochemical applications: correlation between structure, electrical properties and device performance

In this Perspective, the authors review the interplay between structure and charge-transport properties of mesoporous metal oxides, with an emphasis on applications in electrochemical energy storage, catalysis and gas sensing.

Extremely fast electrochromic supercapacitors based on mesoporous WO3 prepared by an evaporation-induced self-assembly

Mesoporous metal oxides consisting of fully interconnected network structures with small pores (20–50 nm) have high surface areas and decreased ion intercalation distances, making them ideal for use in high-performance electrochromic supercapacitors (ECSs). Evaporation-induced self-assembly (EISA), which combines sol–gel chemistry and molecular self-assembly, is a powerful method for the fabrication of mesoporous metal oxides through a solution phase synthesis. Herein, we introduce ultrafast sub-1 s ECSs based on an amorphous mesoporous tungsten trioxide (WO3) that is prepared by EISA. Compared to that of a compact-WO3 film-based device, the performances of an ECS with mesoporous WO3 exhibits a large optical modulation (76% at 700 nm), ultrafast switching speeds (0.8 s for coloration and 0.4 s for bleaching), and a high areal capacitance (2.57 mF/cm2), even at a high current density (1.0 mA/cm2). In addition, the excellent device stability during the coloration/bleaching and charging/discharging cycles is observed under fast response conditions. Moreover, we fabricated a patterned mesoporous WO3 for ECS displays (ECSDs) via printing-assisted EISA (PEISA). The resulting ECSDs can be used as portable energy-storage devices, and their electrochromic reflective displays change color according to their stored energy level. The ECSDs in this work have enormous potential for use in next-generation smart windows for buildings and as portable energy storage displays.