The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by...The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by using the wetness impregnation method. The prepared catalysts were characterized by a series of physico-chemical characterization techniques such as BET surface area, thermo-gravimetric （TG）, transmission electron microscope （TEM） and X-ray photoelectron spectroscopy （XPS）. In addition, the amount of carbon deposits on the surface of the catalysts and the type of the carbonaceous species were discussed by TG. It was found that the bimetallic Pt-Ru/7-A1203 catalysts exhibit both superior catalytic activity and remarkable stability by comparison of monometallic catalysts. During the 500 h stability test, the bimetallic catalyst showed a good performance at 800 ~C in CO2 reforming of CH4, exhibiting an excellent anti-carbon performance with the mass loss of less than 8.5%. The results also indicate that CO2 and CH4 have quite stable conversions of 96.0 % and 94.0 %, respectively. Also, the selectivity of the catalysts is excellent with the products ratio of CO/H2 maintaining at 1.02. Furthermore, it was found in TEM images that the active carbonaceous species were formed during the catalytic reaction, and well-distributed dot-shaped metallic particles with a relatively uniform size of about 3 nm as well as amorphous carbon structures were observed. Combined with BET, TG, TEM tests, it is concluded that the selected bimetallic catalysts can work continuously in a stable state at the high temperature, which has a potential to be utilized for the closed-loop cycle of the solar thermochemical energy storage in future industry applications.展开更多
随着全球工业化进程加快,大量二氧化碳被快速地排放到大气中,产生诸多环境问题。CO_(2)作为一种重要的碳资源,通过加氢制备高附加值化学品近年来逐渐受到研究人员广泛关注。芳烃作为一种基本化工原料,传统上主要靠石油裂解和石脑油重整...随着全球工业化进程加快,大量二氧化碳被快速地排放到大气中,产生诸多环境问题。CO_(2)作为一种重要的碳资源,通过加氢制备高附加值化学品近年来逐渐受到研究人员广泛关注。芳烃作为一种基本化工原料,传统上主要靠石油裂解和石脑油重整来生产,通过CO_(2)加氢制备芳烃可以有效减缓对化石能源的过度依赖。但是CO_(2)的惰性强、活化能垒高、C–C偶联精准调控难,使低温CO_(2)加氢制备芳烃的高效催化剂开发存在巨大挑战。目前,采用氧化物–分子筛复合催化剂体系可以将CO_(2)加氢合成甲醇与甲醇制芳烃反应进行耦合,实现CO_(2)加氢直接合成芳烃。本文通过共沉淀法制备了ZnZrO_(x)复合氧化物,并采用等体积浸渍法引入不同过渡金属(Fe、Cu、Co、Ni),随后将其与商用ZSM-5分子筛物理混合制备了M-ZnZrO_(x)/ZSM-5复合催化剂。在275℃、H_(2)/CO_(2)=3、空速为600 m L/(g·h)的反应条件下,采用质量分数为4%的Fe改性的Fe-ZnZrO_(x)与ZSM-5组成的复合催化剂,芳烃选择性高达80.4%,CO_(2)转化率为5.6%,CO选择性为42.2%。进一步探究了ZnZrO_(x)氧化物上Fe含量对复合催化剂性能的影响,发现Fe含量增加有助于提升反应活性与芳烃选择性;当Fe负载量为8%时,芳烃选择性提升至85.0%。这一研究为在温和条件下通过CO_(2)加氢制备芳烃工业催化剂的开发提供了新思路。展开更多
基金Project(2010CB227103) supported by the National Basic Research Program of ChinaProjects(50930007,50836005) supported by the Key Program of the National Natural Science Foundation of ChinaProject(U1034005) supported by the National Natural Science Foundation of China
文摘The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by using the wetness impregnation method. The prepared catalysts were characterized by a series of physico-chemical characterization techniques such as BET surface area, thermo-gravimetric （TG）, transmission electron microscope （TEM） and X-ray photoelectron spectroscopy （XPS）. In addition, the amount of carbon deposits on the surface of the catalysts and the type of the carbonaceous species were discussed by TG. It was found that the bimetallic Pt-Ru/7-A1203 catalysts exhibit both superior catalytic activity and remarkable stability by comparison of monometallic catalysts. During the 500 h stability test, the bimetallic catalyst showed a good performance at 800 ~C in CO2 reforming of CH4, exhibiting an excellent anti-carbon performance with the mass loss of less than 8.5%. The results also indicate that CO2 and CH4 have quite stable conversions of 96.0 % and 94.0 %, respectively. Also, the selectivity of the catalysts is excellent with the products ratio of CO/H2 maintaining at 1.02. Furthermore, it was found in TEM images that the active carbonaceous species were formed during the catalytic reaction, and well-distributed dot-shaped metallic particles with a relatively uniform size of about 3 nm as well as amorphous carbon structures were observed. Combined with BET, TG, TEM tests, it is concluded that the selected bimetallic catalysts can work continuously in a stable state at the high temperature, which has a potential to be utilized for the closed-loop cycle of the solar thermochemical energy storage in future industry applications.
文摘随着全球工业化进程加快,大量二氧化碳被快速地排放到大气中,产生诸多环境问题。CO_(2)作为一种重要的碳资源,通过加氢制备高附加值化学品近年来逐渐受到研究人员广泛关注。芳烃作为一种基本化工原料,传统上主要靠石油裂解和石脑油重整来生产,通过CO_(2)加氢制备芳烃可以有效减缓对化石能源的过度依赖。但是CO_(2)的惰性强、活化能垒高、C–C偶联精准调控难,使低温CO_(2)加氢制备芳烃的高效催化剂开发存在巨大挑战。目前,采用氧化物–分子筛复合催化剂体系可以将CO_(2)加氢合成甲醇与甲醇制芳烃反应进行耦合,实现CO_(2)加氢直接合成芳烃。本文通过共沉淀法制备了ZnZrO_(x)复合氧化物,并采用等体积浸渍法引入不同过渡金属(Fe、Cu、Co、Ni),随后将其与商用ZSM-5分子筛物理混合制备了M-ZnZrO_(x)/ZSM-5复合催化剂。在275℃、H_(2)/CO_(2)=3、空速为600 m L/(g·h)的反应条件下,采用质量分数为4%的Fe改性的Fe-ZnZrO_(x)与ZSM-5组成的复合催化剂,芳烃选择性高达80.4%,CO_(2)转化率为5.6%,CO选择性为42.2%。进一步探究了ZnZrO_(x)氧化物上Fe含量对复合催化剂性能的影响,发现Fe含量增加有助于提升反应活性与芳烃选择性;当Fe负载量为8%时,芳烃选择性提升至85.0%。这一研究为在温和条件下通过CO_(2)加氢制备芳烃工业催化剂的开发提供了新思路。
