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First Author: PAN Tingting
Abstract:

A facile homogeneous precipitation method driven by synchronous reactions of urea hydrolysis and potassium permanganate reduction is proposed for preparation of MnO2 catalysts. Pure α-MnO2 nanostructures with different morphologies, including nanowires, nanorods and nanoparticles, were obtained by simply tuning the precipitation conditions. The evolution of materials derived from different preparation conditions was investigated via X-ray diffraction, transmission electron microscopy, N2 adsorption, X-ray photoelectron spectroscopy, chemisorption and DFT calculations. The precipitation temperature and time significantly influenced the physiochemical properties of as-prepared catalysts. With increasing precipitation temperature and time, the degree of crystallinity, BET surface area and amount of surface-adsorbed oxygen of α-MnO2 exhibited a substantial increase. The main exposed surface facets varied from (2 0 0), (3 1 0) to (2 1 1) as temperature and time increased. The best precipitation temperature and time were 90 °C and 24 h respectively. The optimal α-MnO2 catalyst demonstrated 100% conversion of 1000 ppm ethyl acetate under the high space velocity of 78,000 h-1 during a 113-h test at 190 °C, outperforming other manganese oxide catalysts and many typical noble metal catalysts in terms of activity and stability. Experimental results and DFT calculations were consistent and indicated that surface oxygen species originating from the (2 1 1) surface of α-MnO2 were most active. This study provides important insights for manipulating the morphology of MnO2 by a facile method and remarkably promoting the performance for ethyl acetate VOC elimination.

Contact the author: DENG Hua
Page Number: 129246
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PubYear: AUG 1 2021
Volume: 417
Publication Name: CHEMICAL ENGINEERING JOURNAL
The full text link: https://doi.org/10.1016/j.cej.2021.129246
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