Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

Abstract

Co6Al2HT hydrotalcite-like compounds were synthesized by three different methods: co-precipitation, microwaves-assisted and ultrasound-assisted methods. The mixed oxides obtained after calcination were studied by several techniques: XRD, TEM, H2-TPR and XPS. They were also tested as catalysts in the reaction of total oxidation of toluene. The physico-chemical studies revealed a modification of the structural characteristics (surface area, morphology) as well as of the reducibility of the formed mixed oxides. The solid prepared by microwaves-assisted synthesis was the most active. Furthermore, a relationship between the ratio of Co 2+ on the surface, the reducibility of the Co-Al mixed oxide and the T50 in toluene oxidation was demonstrated. This suggests a Mars Van Krevelen mechanism for toluene total oxidation on these catalysts.

Silver‐Doped Cobalt (Magnesium) Aluminum Mixed Metal Oxides as Potential Catalysts for Nitrous Oxide Decomposition

“…The H 2 ‐TPR profile of undoped Co 3 Al‐O x revealed the presence of two main reduction peaks, the maxima of which were centered at approximately 465 and 839 °C. The peak at 465°C was assigned to the reduction of Co 3 O 4 , and the peak at 839°C was related to the reduction of Co in Co 2 AlO 4 and CoAl 2 O 4 . Moreover, for the Mg‐containing materials, the formation of MgCo 2 O 4 could not be excluded.…”

ZnCr2O4@ZnO/g‐C3N4: A Triple‐Junction Nanostructured Material for Effective Hydrogen and Oxygen Evolution under Visible Light

“…The high‐resolution O 1s peaks at 529.9, 531.0, and 532.1 eV are characteristic of the hydroxide. The first peak at 529.9 eV corresponds to lattice oxygen O 2− ions, the peak at 531.6 eV is attributed to C−O bonds and indicates the presence of intercalated carbonate ions in the composite, and the final peak is due to the presence of hydroxide groups in the composite …”

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

“…. [28,76] which makes this tool useful for catalysis studies. An example of the capabilities of the E-TEM are the morphological changes occurring on a nanoparticle of Cu (from Cu/ZnO catalyst) under H 2 and H 2 + O 2 environments, as is presented in Figure 6.…”

“…Both EDX and EELS can achieve atomic resolution analysis with the new generations of TEM and under specific conditions. A relatively wide variety of samples can be analysed by TEM: supported or unsupported particles, powders, structured materials… [28,76] which makes this tool useful for catalysis studies. An example of the capabilities of the E-TEM are the morphological changes occurring on a nanoparticle of Cu (from Cu/ZnO catalyst) under H2 and H2 + O2 environments, as is presented in Figure 6.…”