Effect of Doping Metals on OMS-2/γ-Al2O3 Catalysts for Plasma-Catalytic Removal of o-Xylene

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• 作者：Lian Wang ; Changbin Zhang ; Hong He ; Fudong Liu ; Caixia Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 24, 2016
• 年：2016
• 卷：120
• 期：11
• 页码：6136-6144
• 全文大小：624K
• ISSN：1932-7455

文摘

A series of Pd-, Ce-, Co-, and Ti- doped OMS-2 catalysts were prepared by a one-step hydrothermal method. The removal of o-xylene by a combination of metal-doped OMS-2/γ-Al₂O₃ catalysts and nonthermal plasma was systematically investigated. Catalysts were characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), and H₂ temperature-programmed reduction (H₂-TPR). Among the metal-doped OMS-2/γ-Al₂O₃ catalysts used in the plasma-catalytic process, Pd_0.07-OMS-2/γ-Al₂O₃ and Ce_0.07-OMS-2/γ-Al₂O₃ exhibited excellent catalytic activity for o-xylene removal with 100% o-xylene conversion, above 60% CO₂ selectivity, and above 80% (CO+CO₂) (i.e., CO_x) yield at a low specific energy density of 18 J/L. These two catalysts had high redox ability, abundant surface defects for absorbing and activating oxygen, and more active surface oxygen species than Co_0.07-OMS-2/γ-Al₂O₃ and Ti_0.07-OMS-2/γ-Al₂O₃ catalysts, therefore resulting in much higher catalytic activity in the oxidation of o-xylene. The concentration of byproducts produced by nonthermal plasma such as O₃ and NO_x was greatly reduced when using these metal-doped OMS-2/γ-Al₂O₃ catalysts. Pd_0.07-OMS-2/γ-Al₂O₃ had the highest suppression ability for O₃ and NO_x, which were reduced to near zero. Moreover, Fourier transform infrared spectroscopy (FT-IR) results suggested that introduction of metal-doped OMS-2/γ-Al₂O₃ catalysts could oxidize o-xylene to CH₃CHO and/or CH₃COOH and further oxidize CH₃CHO and/or CH₃COOH to CO or CO₂.