CAJ | 학술논문

采用共沉淀法制备了不同铈铬比例的 CeO2-CrOx复合氧化物(Ce/Cr 摩尔比分别为9/1、4/1、2/1、1/1、1/2、1/4、1/8)以及单纯的CeO2和Cr2O3,并研究了各催化剂对1,2-二氯乙烷(DCE)的催化氧化性能.结果表明,相较于单纯的CeO2,不同铈铬比例的复合氧化物催化剂对DCE的催化氧化活性有明显提高,其中Ce/Cr摩尔比为2/1的CeO2-CrOx复合氧化物上DCE的氧化活性最好,且只有极微量的含氯等副产物产生;随着Ce/Cr摩尔比减小,对HCl的选择性有下降的趋势.通过X射线衍射(XRD)、N2吸附/脱附(BET)、紫外拉曼(UV-Raman)光谱、H2程序升温还原(H2-TPR)、NH3程序升温脱附(NH3-TPD)等实验技术,研究了铈铬比例对铈铬复合氧化物的物理化学性质的影响.结果表明,适当比例Ce-Cr的复合,形成了结构较稳定的Ce-Cr-O固溶体,提高了催化剂活性氧物种的流动性,催化剂表面酸量及强弱酸比例,从而有利于DCE的吸附活化,进一步脱氯降解以及深度氧化.
채용공침정법제비료불동시락비례적 CeO2-CrOx복합양화물(Ce/Cr 마이비분별위9/1、4/1、2/1、1/1、1/2、1/4、1/8)이급단순적CeO2화Cr2O3,병연구료각최화제대1,2-이록을완(DCE)적최화양화성능.결과표명,상교우단순적CeO2,불동시락비례적복합양화물최화제대DCE적최화양화활성유명현제고,기중Ce/Cr마이비위2/1적CeO2-CrOx복합양화물상DCE적양화활성최호,차지유겁미량적함록등부산물산생;수착Ce/Cr마이비감소,대HCl적선택성유하강적추세.통과X사선연사(XRD)、N2흡부/탈부(BET)、자외랍만(UV-Raman)광보、H2정서승온환원(H2-TPR)、NH3정서승온탈부(NH3-TPD)등실험기술,연구료시락비례대시락복합양화물적물이화학성질적영향.결과표명,괄당비례Ce-Cr적복합,형성료결구교은정적Ce-Cr-O고용체,제고료최화제활성양물충적류동성,최화제표면산량급강약산비례,종이유리우DCE적흡부활화,진일보탈록강해이급심도양화.
CeO2, Cr2O3, and CeO2-CrOx mixed oxides with molar ratios of Ce to Cr of 9/1, 4/1, 2/1, 1/1, 1/2, 1/4, and 1/8 were prepared by coprecipitation. The catalytic performance of 1,2-dichloroethane (DCE) decomposition was evaluated on al the catalysts. The results indicate that CeO2-CrOx mixed oxides with different Ce/Cr molar ratios showed higher performance for the removal of DCE compared with pure CeO2. The CeO2-CrOx mixed oxide with Ce/Cr molar ratio of 2/1 exhibited the highest catalytic activity of the samples, generating only smal amounts of chlorinated by-products during the decomposition of DCE. The selectivity for HCl decreased as the molar ratio of Ce to Cr decreased. The catalysts were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), UV-Raman spectroscopy, hydrogen temperature-programmed reduction (H2-TPR), and ammonia temperature-programmed desorption (NH3-TPD) to study the effect of the Ce/Cr molar ratio on the physicochemical performance of the catalysts. An appropriate molar ratio of Ce to Cr formed a more stable Ce-Cr-O solid solution, which increased the mobility of reactive oxygen species, oxidative ability, surface acid content and the ratio of strong acidity, promoting the adsorption, activation and deep oxidation of DCE.