Influence of CeO2 morphology on the catalytic oxidation of ethanol in air

Guilin Zhou,Baoguo Gui,Hongmei Xie,Fang Yang,Yong Chen,Shengming Chen,Xuxu Zheng 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

Nano-CeO2 catalysts of different shapes were synthesized at different hydrothermal crystallizationtemperatures from an alkaline aqueous solution. X-ray diffraction (XRD), transmission electronmicroscope (TEM), and H2 temperature-programmed reduction (H2-TPR) were used to study thesynthesized nano-CeO2 catalyst samples. The catalytic properties of the prepared nano-CeO2 catalystsfor the catalytic oxidation of ethanol in air were also investigated. TEM analysis showed that CeO2nanorod and nanocube catalysts have been synthesized at hydrothermal crystallization temperatures of373 K and 453 K, respectively. XRD results showed that the synthesized nano-CeO2 catalysts have similarcubic fluorite structures. H2-TPR results indicated that CeO2 nanorod and nanocube catalysts exhibitdifferent reduction behaviors for H2 and that the nanorod catalyst has better low-temperature reductionperformance than the nanocube catalyst. Ethanol catalytic oxidation results indicated that oxidation andcondensation products (including acetaldehyde, acetic acid, CO2, and ethyl acetate) have been producedfrom the prepared catalysts. The ethyl acetate and acetic acid can be ignited by ethanol at lowtemperature on the CeO2(R) catalyst to give low catalytic combustion temperature for ethyl acetate andacetic acid molecules. CeO2 nanorods gave ethanol oxidation conversion rates above 99.2% at 443 K andCO2 selectivity exceeding 99.6% at 483 K, while CeO2 nanocubes gave ethanol oxidation conversion ratesof about 95.1% until 508 K and CO2 selectivity of only 93.86% at 543 K. CeO2 nanorod is a potential lowcostand effective catalyst for removing trace amounts of ethanol to purify air.

Phenyl VOCs catalytic combustion on supported CoMn/AC oxide catalyst

Guilin Zhou,Xiaoling He,Sheng Liu,Hongmei Xie,Min Fu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Supported CoMn/AC composite oxide catalysts were prepared by a typical impregnation methodat different calcination temperatures. The prepared CoMn/AC catalysts were characterized, and thecatalytic activity of the prepared supported CoMn/AC oxide catalysts was also investigated by thecatalytic combustion of phenyl volatile organic compounds (VOCs) (benzene, toluene, andethylbenzene). XRD and XPS results indicated that MnCo2O4 and CoMn2O4 were the main crystalphase species in the prepared supported CoMn/AC oxide catalysts. The active components wereobserved to be highly dispersed and had small crystal sizes. The toluene catalytic combustion resultsdemonstrated that the CAT350 catalyst had higher toluene catalytic combustion activity than theCTA250, CAT300, and CAT400 catalysts. The toluene catalytic combustion conversion of the CAT350catalyst exceeded 93.5% at 235 8C, with a decreased toluene concentration in air of less than 130 ppm at250 8C. The order of toluene catalytic activity of the supported CoMn/AC oxide catalystswas as follows:CAT250 < CAT300 CAT400 < CAT350. The catalytic combustion activity and stability of the CAT350catalyst also increased with the increase in reaction temperature. The catalytic activity of the CAT350catalyst was investigated to bring about the complete oxidation of benzene, ethylbenzene, and toluene. The combustibility of phenyl VOCs on the CAT350 catalyst was observed to follow the orderbenzene < ethylbenzene < toluene. Therefore, the differences in the phenyl VOC catalytic combustionperformances of the supported CoMn/AC composite oxide catalysts can be attributed to the differentphysical chemistry properties of the phenyl VOC molecules and the catalyst.

Application of copper sulfate based fenton-like catalyst in degradation of quinoline

Zhaojie Jiao,Haifeng Gong,Ye Peng,Guilin Zhou,Xianming Zhang,Xu Gao,Yunqi Liu 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.5

In the practical application of water treatment, the Fenton reaction usually works at a lower pH. To overcome the above shortcomings, a Fenton-like reaction system with copper sulfate as a catalyst was proposed. In this paper, quinoline was used as the target pollutant and the effects of catalyst dosage, H₂O₂ dosage, reaction temperature, and initial concentration of quinoline and pH on the removal effect were investigated, and the evolution in pH and hydroxyl radical concentration during reaction, as well as the possible catalytic mechanism and degradation pathway were clarified. The results show that under a catalyst dosage of 0.4 g・L<SUP>-1</SUP>, a H₂O₂ dosage of 196 mmol・L<SUP>-1</SUP>, a quinoline concentration of 100 mg・L<SUP>-1</SUP> and a temperature of 75°C, the removal of quinoline and total organic carbon (TOC) reaches 99.5% and 87.2% in 65 min, respectively. Furthermore, the copper sulfate-driven homogeneous Fenton system exhibits a superior adaptability to pH in the range of 3.8 to 8.8. In the degradation of quinoline, ·OH radicals may attack the nitrogen ring and the benzene ring in sequence. The work provides a technical support for the treatment of organic wastewater, and shows promising in practical applications.

Catalytic combustion of volatile aromatic compounds over CuO-CeO2 catalyst

Hongmei Xie,Qinxiang Du,Hui Li,Guilin Zhou,Shengming Chen,Zhaojie Jiao,Jianmin Ren 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.7

Ce1−xCuxO2 oxide solid solution catalysts with different Ce/Cu mole ratios were synthesized by the one-pot complex method. The prepared Ce1−xCuxO2 catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). Their catalytic properties were also investigated by catalytic combustion of phenyl volatile organic compounds (PVOCs: benzene, toluene, xylene, and ethylbenzene) in air. XRD analysis confirmed that the CuO species can fully dissolve into the CeO2 lattice to form CeCu oxide solid solutions. XPS and H2-TPR results indicated that the prepared Ce1−xCuxO2 catalysts contain abundant reactive oxygen species and superior reducibility. Furthermore, the physicochemical properties of the prepared Ce1−xCuxO2 catalysts are affected by the Ce/Cu mole ratio. The CeCu3 catalyst with Ce/Cu mole ratio of 3.0 contains abundant reactive oxygen species and exhibits superior catalytic combustion activity of PVOCs. Moreover, the ignitability of PVOCs is also affected by the respective physicochemical properties. The catalytic combustion conversions of ethylbenzene, xylene, toluene, and benzene are 99%, 98.9%, 94.3%, and 62.8% at 205, 220, 225, and 225 oC, respectively.

Reduction of CO2 to CO via reverse water-gas shift reaction over CeO2 catalyst

Bican Dai,Shiquan Cao,Hongmei Xie,Guilin Zhou,Shengming Chen 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.2

CeO2 catalysts with different structure were prepared by hard-template (Ce-HT), complex (Ce-CA), and precipitation methods (Ce-PC), and their performance in CO2 reverse water gas shift (RWGS) reaction was investigated. The catalysts were characterized using XRD, TEM, BET, H2-TPR, and in-situ XPS. The results indicated that the structure of CeO2 catalysts was significantly affected by the preparation method. The porous structure and large specific surface area enhanced the catalytic activity of the studied CeO2 catalysts. Oxygen vacancies as active sites were formed in the CeO2 catalysts by H2 reduction at 400 oC. The Ce-HT, Ce-CA, and Ce-PC catalysts have a 100% CO selectivity and CO2 conversion at 580 oC was 15.9%, 9.3%, and 12.7%, respectively. The highest CO2 RWGS reaction catalytic activity for the Ce-HT catalyst was related to the porous structure, large specific surface area (144.9m2∙g−1) and formed abundant oxygen vacancies.