Beneficial Effect of β‐Cyclodextrin Assisted Synthesis of CuO/Hydroxyapatite Catalyst in Toluene Oxidation

Abstract

Two hydroxyapatite supported CuO (10 wt% Cu) catalysts were prepared using the wet impregnation method via the conventional process and with the addition of native β-cyclodextrin using Cu(NO 3 ) 2 .3H 2 O as copper precursor and adopting a ratio of β-cyclodextrin to copper of 0.1. After the impregnation step, the materials were dried at 80 °C and calcined in flowing dry air at 400 °C. The copper supported materials were characterized in the dried state and after calcination by means of conventional methods including X-ray diffraction, TG-MS, H 2 -TPR-MS, Raman spectroscopy, UV-vis-DR, ToF-SIMS and XPS. It was found that βcyclodextrin hasd a profound impact on the final properties of the catalysts, both in terms of reducibility and dispersion of active species. It is suggested that at the early stages of the calcination, some hydroxyl groups of the β-CD units in close contact with Ca 2 + of hydroxyapatite could play the role of spacers between the copper-based entities thus minimizing the aggregation process of the CuO nanoparticles. Finally, these copper oxide catalysts prepared from β-cyclodextrin were able to oxidize toluene more efficiently than the conventional catalyst. The copper oxide particles generated by the thermal decomposition of Cu 2 (OH) 3 (NO 3 ) were smaller than those formed with copper nitrate alone and exhibited a higher reducibility, two key determinants for VOC total oxidation on transition metal oxides.[a] M.

Computational Fluid Dynamics Simulation of a High-Throughput Catalytic Fixed-Bed Reactor for Total Oxidation of Methane

“…The lowest amount of catalyst required to achieve a notable methane conversion corresponds to 0.073 g. The catalyst weights of 0.113 and 0.153 g are selected to realize a well-distributed space-time interval, as determined by the minimum and maximum catalyst weights. Remark that for a given space time, the amount of inert in the reaction zone is calculated by subtracting the specified amount of catalyst from the total weight of 1.3 g. The catalyst used in the presented study is prepared according to the method described in the work of Ibrahim et al 30 Second, when the methane partial pressure is set at 2.91, 4.52, and 7.97 kPa, the oxygen partial pressure is kept constant at 32.65 kPa, and the total outlet gas pressure is kept at 500 kPa g by the back-pressure valve. Similarly, when the oxygen…”

“…The present work aims at developing a CFD model that describes the performance of a β-cyclodextrin-Cu/hydroxyapatite (βCD-Cu/HAP) catalyst for the total oxidation of methane, a prominent VOC, in a high-throughput fixed-bed reactor exclusively designed to screen and develop new catalysts. − The βCD-Cu/HAP catalyst is selected in this study as the incorporation of β-cyclodextrin enhances the catalytic performance of CuO-supported HAP due to the enhanced Cu dispersion, as described by Ibrahim et al . The calculated methane conversion is compared to experimental data gathered over a wide range of operating conditions, including the space time, reaction temperature, and partial pressure of both methane and oxygen.…”