Facile synthesis of size-controlled Ag supported on WO3 nanorods and their application as novel and active catalyst in oxidant-free dehydrogenation of benzyl alcohols

Porous Mullite Ceramic Modification with Nano-WO3

Mullite and mullite-alumina ceramics materials with dominance of the mullite phase are used in different areas of technology and materials science. Porous mullite ceramics materials can be used simultaneously as refractory heat insulators and also as materials for constructional elements. The purpose of this work was to investigate the WO₃ nanoparticle influence on the evolution of the aluminum tungstate and zircon crystalline phases in mullite ceramics due to stabilization effects caused by different microsize ZrO₂ and WO₃. The use of nano-WO₃ prevented the dissociation of zircon in the ceramic samples with magnesia-stabilized zirconia (MSZ), increased porosity by approximately 60 ± 1%, increased the intensity of the aluminum tungstate phase, decreased bulk density by approximately 1.32 ± 0.01 g/cm³, and increased thermal shock resistance by ensuring a loss of less than 5% of the elastic modulus after 10 cycles of thermal shock.

CdS/WO3 S-scheme heterojunction with improved photocatalytic CO2 reduction activity

The anthropogenic emission of CO₂ in the environment affected our atmosphere, which caused a rapid change in the climate. It needs to reduce the excess CO₂ from the environment to maintain sustainability and keep it green. In this work, we have fabricated a CdS decorated WO₃ nanocomposite, improving the reduction ability of CO₂ into CO and CH₄ selectively in visible light. The construction of the heterojunction improved the stability of CdS with WO₃. It synergistically resulted in ~7.7 times the higher yield of CO and 2.3 times the higher yield of CH₄ than CdS using 20 wt% CdS decorated WO₃ nanocomposite in a mixture of N,N-dimethylformamide, triethylamine, and water in a 3:1:1 ratio. The 20 wt% CdS on WO₃ nanocomposite has proven an effective and selective photocatalyst with the relative yield of methanol up to four cycles. The nanocomposite photocatalysts were analyzed using instrumental techniques, such as XRD, XPS, HR-TEM, FTIR, TGA-DTA, UV-vis, PL spectroscopy, and PEC analysis.

Highly dispersed silver nanoparticles supported on hydroxyapatite catalyst with different morphology for CO oxidation

Supported nano-silver (nano-Ag) catalysts have been widely used in heterogeneous catalysis. However, because of their poor thermal stability, it restricts the practical application. In order to solve this issue, we...

Atomically Dispersed Co Clusters Anchored on N-doped Carbon Nanotubes for Efficient Dehydrogenation of Alcohols and Subsequent Conversion to Carboxylic Acids

The catalytic dehydrogenation of readily available alcohols to high value-added carbonyl compounds is a research hotspot with scientific significance. Most of the current research about this reaction is performed with noble metal-based homogeneous catalysts of high price and poor reusability. Herein, highly dispersed Co-cluster-decorated N-doped carbon nanotubes (Co/N-CNTs) were fabricated via a facile strategy and used for the dehydrogenation of alcohols with high efficiency. Various characterization techniques confirmed the presence of metallic Co clusters with almost atomic dispersion, and the N-doped carbon supports also enhanced the catalytic activity of Co clusters in the dehydrogenation reaction. Aldehydes as dehydrogenation products were further transformed in situ to carboxylic acids through a Cannizzaro-type pathway under alkaline conditions. The reaction pathway of the dehydrogenation of alcohols was clearly confirmed by theoretical calculations. This work should provide an effective and simple approach for the accurate design and synthesis of small Co-clusters catalysts for the efficient dehydrogenation-based transformation of alcohols to carboxylic acids under mild reaction conditions.

Visible light assisted production of methanol from CO2 using CdS@CeO2 heterojunction

The production of methanol from CO₂ is highly desirable in present scenario due to the excessive CO₂ emission. Several photocatalytic materials have been developed for reduction of CO₂ into methanol under mild conditions, but things need to be developed soon. In the present work, the solvothermal process had synthesized high surface area CeO₂ supported CdS nanocomposite. The catalytic amount of CdS@CeO₂ heterojunction materials was highly active to produce methanol and CO from CO₂. CdS@CeO₂ heterojunction demonstrated a good formation of methanol (1534 μmol-g^-1) and CO (213 μmol-g^-1) under similar conditions. CdS@CeO₂ heterojunction materials were studied using several characteristic techniques, such as XRD, XPS, HR-TEM, UV-vis, FTIR, PL, and Raman spectroscopy, physisorption and EIS analysis. CdS@CeO₂ nanocomposite demonstrated excellent activity and stability with no leaching of metal content at the end of the sixth run.

A new porous Co(ii)-metal–organic framework for high sorption selectivity and affinity to CO2 and efficient catalytic oxidation of benzyl alcohols to benzaldehydes

A new porous Co(ii)-MOF I has been prepared. Gas sorption and catalytic experiments show that the guest-free sample I′ shows the high capacity and selectivity to CO₂ over CH₄ and catalytically oxidize benzyl alcohols efficiently into benzaldehydes.

Elnouby M, Gouda MH, Elessawy NA, Santos DMF. Effect of the Morphology of Tungsten Oxide Embedded in Sodium Alginate/Polyvinylpyrrolidone Composite Beads on the Photocatalytic Degradation of Methylene Blue Dye Solution

Tungsten oxide nanostructures were modified by oxygen vacancies through hydrothermal treatment. Both the crystalline structure and morphological appearance were completely changed. Spherical WO₃·H₂O was prepared from tungstic acid solution by aging at room temperature, while rod-like WO₃·0.33H₂O was prepared by hydrothermal treatment of tungstic acid solution at 120 °C. These structures embedded in sodium alginate (SA)/polyvinylpyrrolidone (PVP) were synthesized as novel porous beads by gelation method into calcium chloride solution. The performance of the prepared materials as photocatalysts is examined for methylene blue (MB) degradation in aqueous solutions. Different operation parameters affecting the dye degradation process, such as light intensity, illumination time, and photocatalyst dosage are investigated. Results revealed that the photocatalytic activity of novel nanocomposite changed with the change in WO₃ morphology. Namely, the beads with rod nanostructure of WO₃ have shown better effectiveness in MB removal than the beads containing WO₃ in spherical form. The maximum degradation efficiency was found to be 98% for WO₃ nanorods structure embedded beads, while the maximum removal of WO₃ nanospheres structure embedded beads was 91%. The cycling-ability and reuse results recommend both prepared structures to be used as effective tools for treating MB dye-contaminated wastewaters. The results show that the novel SA/PVP/WO₃ nanocomposite beads are eco-friendly nanocomposite materials that can be applied as photocatalysts for the degradation of cationic dyes in contaminated water.