Direct coating copper–zinc–aluminum oxalate with H-ZSM-5 to fabricate a highly efficient capsule-structured bifunctional catalyst for dimethyl ether production from syngas

This work reports a facile strategy for preparing a highly efficient capsule bifunctional catalyst by direct coating copper–zinc–aluminum oxalate with H-ZSM-5, showing outstanding catalytic properties for dimethyl ether production from syngas.

Ultrasound assisted dispersion of Bi2Sn2O7-C3N4 nanophotocatalyst over various amount of zeolite Y for enhanced solar-light photocatalytic degradation of tetracycline in aqueous solution

Bi₂Sn₂O₇-C₃N₄/Y nanophotocatalyst with various ratios of zeolite and high activity under simulated solar light irradiation were successfully synthesized using ultrasound-assisted dispersion method. The effect of different amounts of zeolite (10, 20 and 30 wt%) on the photocatalytic degradation of antibiotic tetracycline was investigated. The as-prepared nanophotocatalysts were characterized by XRD, FESEM, EDX, BET, FTIR, DRS and pH_pzc techniques. The degradation results demonstrated that, Bi₂Sn₂O₇-C₃N₄/Y(10) nanophotocatalyst with a degradation efficiency of about 80.4% is an optimum sample. This result can be attributed to the zeolite as a support that prevented the accumulation of Bi₂Sn₂O₇-C₃N₄ active phase and increased access to active sites. Furthermore, it enhanced the adsorption capacity of tetracycline on the photocatalyst surface; that it is beneficial for tetracycline photocatalytic oxidation. Also the results of the DRS analysis indicated that the sharp absorption edge for optimum sample Bi₂Sn₂O₇-C₃N₄/Y at about 480 nm and was active in the visible light range. Eventually, different operational parameters such as photocatalyst loading, concentrations of pollutant and pH solution were investigated. In addition, the degradation mechanism was suggested for TC removal.

Sono-precipitation of Ag2CrO4-C composite enhanced by carbon-based materials (AC, GO, CNT and C3N4) and its activity in photocatalytic degradation of acid orange 7 in water

Enhancing the photocatalytic activity of Ag₂CrO₄ with coupled carbon-based materials like activated carbon, graphene oxide, carbon nanotubes and carbon nitride has been investigated in removal of Acid Orange 7 from wastewater. Sono precipitated Ag₂CrO₄-C composite based photocatalysts were characterized by XRD, BET, FESEM, FTIR and UV-vis DRS and the photocatalytic activity of theses samples was evaluated in terms of degradation amount of acid orange 7 under visible light irradiations. BET analysis showed that with addition of carbon based materials, the specific surface area of the Ag₂CrO₄-C composite increased. XRD analysis indicated that the crystallinity of Ag₂CrO₄ peaks decreased after addition of all studied carbon-based materials and C₃N₄ has lowered the crystallinity of Ag₂CrO₄ less than others. Higher crystallinity has the positive effect of higher photocatalytic activity because among above mentioned composites, Ag₂CrO₄-C₃N₄ photocatalyst exhibited higher photocatalytic activity and stability under visible light irradiations. DRS analysis confirmed good match of electronic structures of Ag₂CrO₄ and C₃N₄. On the other hand Ag₂CrO₄ and C₃N₄ formed heterojunction which separates photo-generated electron-hole pairs effectively. Also evaluation of photocatalytic reaction in various operating parameters showed Ag₂CrO₄-C₃N₄ had the highest photocatalytic activity in neutral pH and 1g/L of catalyst loading.

Sono-coprecipitation synthesis and physicochemical characterization of CdO-ZnO nanophotocatalyst for removal of acid orange 7 from wastewater

In this research, CdO-ZnO nano-photocatalysts were synthesized in various compositions by ultrasound assisted co-precipitation method. The samples were investigated via analyses of XRD, FESEM, BET, DRS, FTIR and EDX dot mapping to determine the physical, chemical and optical properties of the nanocomposites. Successful synthesis of CdO-ZnO photocatalyst in crystalline form was confirmed by XRD analysis resulting lower crystallite sizes for ZnO compared to CdO in the composites. The FESEM analysis demonstrated a nanostructured catalyst with a distinct decrease in particle size by addition of CdO to ZnO photocatalyst. The particle size distribution analysis determined an average particle size of 67.9 for the CdO25ZnO75-SCP sample. According to EDX dot mapping results, the Cd dispersion has been enhanced for the case of sonicated samples. Consequently, these cases have represented higher BET surface area results. Degradation of azo dye from synthetic wastewater was performed in order to evaluate the photocatalytic activity of the samples. The characterization analyses along with the performance tests concluded better properties in the case of ultrasound assisted co-precipitation. The investigation of various compositions resulted the best performance for CdO50ZnO50-SCP nanophotocatalyst reporting 69% of contaminant degradation during 140min of the experiment.

Sono-sulfated zirconia nanocatalyst supported on MCM-41 for biodiesel production from sunflower oil: Influence of ultrasound irradiation power on catalytic properties and performance

Sono-sulfated zirconia nanocatalyst supported on MCM-41 was prepared by an ultrasound-assisted impregnation/hydrothermal hybrid method. The effect of irradiation power was studied by changing power of the sonication (30, 60 and 90W) during the synthesis which led to different physiochemical properties of the nanocatalyst. XRD, FESEM, EDX, FTIR and BET analyses exhibited smaller particles with higher surface area and less population of particle aggregates at highly irradiated nanocatalysts. The nanocatalyst irradiated at 90W for 30min showed a very narrow particle size distribution. About 59% of nanocatalyst particles were in the range of 1-30nm. The performance of investigated nanocatalysts in biodiesel production from sunflower oil showed ultrasound-assisted synthesized nanocatalysts had higher conversion in comparison to non-sonicated catalyst. Biodiesel conversion in catalyst with 90W and 30min ultrasonic irradiation exceeded 96.9% under constant condition at 60°C reaction temperature, methanol/oil molar ratio of 9:1 and 5% catalyst concentration. After five cycles, biodiesel conversion of non-sonicated catalyst was well maintained in a high extend (71.4%) while biodiesel conversion of non-sonicated catalyst barely reached to 43.5%. Among sonicated nanocatalysts, with increasing power of irradiation, the nanocatalyst represented higher conversion and reusability.

Citrate complexation microwave-assisted synthesis of Ce0.8Zr0.2O2 nanocatalyst over Al2O3 used in CO oxidation for hydrogen purification: influence of composite loading and synthesis method

Nanostructured Ce_0.8Zr_0.2O₂/Al₂O₃ composite catalyst was synthesized by modified citrate complexation method. Utilizing microwave combustion endowed the sample with more uniform and homogenous pattern leading to better CO oxidation.

One-pot hydrothermal synthesis of ZSM-5–CeO2 composite as a support for Cr-based nanocatalysts: influence of ceria loading and process conditions on CO2-enhanced dehydrogenation of ethane

The oxidative dehydrogenation of ethane in the presence of CO₂ was investigated over a series of Cr impregnated ZSM-5–CeO₂ nanocatalysts with the aim of exploring the ceria addition effect.

Altering C2H4/C3H6 yield in methanol to light olefins over HZSM-5, SAPO-34 and SAPO-34/HZSM-5 nanostructured catalysts: influence of Si/Al ratio and composite formation

HZSM-5 zeolites with various Si/Al ratios were synthesized by hydrothermal method and the sample with optimum Si/Al ratio combined with SAPO-34. In MTO reaction, SAPO-34/HZSM-5 composite shows high activity and selectivity toward light olefins.

Conversion of dimethyl ether to toluene under an O2 stream over W/HZSM-5 catalysts

The direct conversion of dimethyl ether (DME) to toluene without other aromatics is realized over W/HZSM-5 catalysts with high W contents.