摘要
采用沉淀-沉积法制备出w（Co）=10%、15%、20%和25%的Co/TiO2催化剂,并用于催化CO2甲烷化反应。通过XRD、TEM、N2吸附-脱附、H2程序升温还原（H2-TPR）和CO2程序升温脱附（CO2-TPD）对催化剂进行了表征与测试。结果表明,Co的负载影响了催化剂中Co3O4晶粒尺寸、比表面积、孔径以及催化剂的还原性能,且Co物种与TiO2载体发生了强相互作用。其中,w（Co）=20%的Co/TiO2催化剂中Co颗粒平均尺寸约为8nm,比表面积及孔径分别为40.9 m2/g和6.96 nm,且Co分散度达10.1%,从而更有利于CO2甲烷化反应。此外,w（Co）=20%的Co/TiO2催化剂表面具有最大的中强碱位量（28μmol/g）,从而可活化更多的CO2。活性测试结果表明,当反应温度为400℃、压力0.5 MPa、原料气空速3 600 m L/（g·h）、V（H2）/V（CO2）=4时,w（Co）=20%的Co/TiO2催化剂的活性最好,其CO2转化率和CH4选择性可分别达到69.9%和98.3%,且在20 h内保持稳定。
A series of Co/TiO2 catalysts with different Co loadings amounts[w（Co） = 10% ,15% ,20% and 25% ] were prepared by deposition-precipitation method. The catalytic performances for the CO2 methanation were investigated. These catalysts were characterized by XRD, TEM, N2 adsorption-desorption, temprature programmed reduction of hydrogen （ H2-TPR ） ,and temperature programmed desorption of carbon dioxide （ CO2- TPD）. The results showed the CO loading amount could affect the crystallite size of Co304 ,the BET surface area and reducing properties of catalysts, and a strong interaction was observed between CO species and TiO2. The Co/TiO2 catalyst with 20% Co loading amount exhibited a smaller Co particle size of 8 run and a good Co dispersion of 10. 1% ,and the BET surface area and pore size were 40. 9 m2/g and 6. 96 nm,respectively,which would favor the CO2 methanation. In addition,a maximum medium basicity of 28 μmol/g was observed on the Co/TiO2 catalyst with 20% CO loading amount,indicating more CO2 molecules were activated on the catalyst surface. The activity test indicated that the optimal catalytic performance was obtained over Co/TiO2 catalyst with 20% CO loading amount showed the best catalytic performance and kept stable in 20 h, under the conditions of 400 ℃ ,0. 5 MPa ,a gaseous hourly space velocity of 3 600 mL/（ g · h） and V（H2）/V（ CO2 ） =4, and the CO2 conversion and methane selectivity were 69.9% and 98.3%, respectively.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2018年第1期72-80,共9页
Fine Chemicals
基金
国家自然科学基金(21006013)
广西自然科学基金(2016GXNSFFA380015)
广西石化资源加工及过程强化技术重点实验室主任课题(2016Z003)~~
关键词
CO2加氢
甲烷化
Co基催化剂
Co负载量
金属-载体强相互作用
表面碱量
催化与分离提纯技术
CO2 hydrogenation
methanation
cobalt-based catalyst
Co loading amount
metal-support interaction
surface base amount
catalysis, separation and purification technology
