Al、Ti或Zr改性对包埋式Ni@SiO_(2)催化剂甲烷部分氧化制合成气性能的影响  

Effects of Al,Ti or Zr modification on performances of embedded Ni@SiO_(2) catalysts for partial oxidation of methane to syngas

作　　者：邵景玲 李杰 费兆阳[2] 李雷 SHAO Jinging;LI Jie;FEI Zhaoyang;LI Lei(School of Chemistry and Chemical Engineering,Yancheng Institute of Technology,Yancheng 224051,Jiangsu,China;State Key Laboratory of Materials-Oriented Chemical Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China)

机构地区：[1]盐城工学院化学化工学院,江苏盐城224051 [2]南京工业大学材料化学工程国家重点实验室,江苏南京211816

出　　处：《低碳化学与化工》2024年第8期66-73,共8页Low-Carbon Chemistry and Chemical Engineering

基　　金：材料化学工程国家重点实验室自主课题(SKL-MCE-22B06)。

摘　　要：包埋式结构催化剂能够有效地阻止活性组分的高温烧结,实现甲烷部分氧化(POM)反应高效制合成气。采用Stöber法制备了包埋式Ni@SiO_(2)催化剂,并引入Al、Ti或Zr对其进行改性制得相应的改性催化剂。采用X射线衍射(XRD)、透射电镜(TEM)和N_(2)吸/脱附等对催化剂的晶相结构、形貌和织构性质等进行了表征,并研究了改性对催化剂在POM反应制合成气(原料气组成:V(CH4):V(O_(2)):V(N_(2))为2:1:3、流量为60mL/min、压力为0.1MPa、空速为7.2L/(g·h)和反应时间为22h)中催化性能的影响。结果表明,与Ni@SiO_(2)相比,Ni@Al-SiO_(2)可促进甲烷的活化,其催化性能明显提升,Ni@Ti-SiO_(2)和Ni@Zr-SiO_(2)因活性位点的阻碍而催化性能降低。在700℃下,反应稳定后,Ni@SiO_(2)和Ni@Al-SiO_(2)的CH4转化率分别为86%和80%,CO选择性均为90%左右,H_(2)选择性分别为93%和88%。经8 h稳定性测试后,与Ni@SiO_(2)相比,Ni@Ti-SiO_(2)和Ni@Zr-SiO_(2)的CH4转化率、CO选择性和H_(2)选择性均明显降低。活性位点的减少和积炭是导致催化剂失活的主要原因,积炭未造成活性位点的完全覆盖,催化剂仍能保持稳定的POM催化性能。The embedded catalysts can effectively prevent the sintering behavior,and realize the high activity in partial oxidation of methane(POM)reaction.The embedded Ni@SiO_(2) catalysts were prepared by Stöber method,and the Al,Ti or Zr were used to modify them.Various characterizations,such as X-ray diffraction(XRD),transmission electron microscope(TEM)and N_(2) adsorption/desorption,were employed to the characterizations of crystalline phase structures,morphologies and texture parameters of catalysts.The effects of modification of catalysts on the catalytic POM performance were further investigated under the feed gases compositions ofV(CH4):V(O_(2)):V(N_(2))of 2:1:3,gas flow rate of 60 mL/min,pressure of 0.1 MPa,space velocity of 7.2 L/(g·h)and reaction time of 22 h.The results show that compared with Ni@SiO_(2) catalyst,the Ni@Al-SiO_(2)catalyst can promote the activation of methane and its catalytic performance is improved.However,the Ni@Ti-SiO_(2) and Ni@Zr-SiO_(2) catalysts show the decreased catalytic performances because of the obstruction of active sites.At 700℃,the CH4 conversation rates of Ni@Al-SiO_(2) and Ni@SiO_(2) are 86%and 80%,the CO selectivities are both about 90%,and the H_(2) selectivities are 93%and 88%,respectively.However,compared with Ni@SiO_(2)catalyst,the CH4 conversion rates,CO selectivities and H_(2) selectivities of Ni@Ti-SiO_(2) and Ni@Zr-SiO_(2) are significantly reduced.It reveals that the catalyst deactivation can be mainly ascribed to the loss of active sites and carbon deposit.But the active sites are not completely covered by deposited carbon,and the catalyst still maintain robust catalytic POM performance.

关 键 词：Ni@SiO_(2)催化剂 包埋式结构 催化剂改性 甲烷部分氧化 积炭 

分 类 号：TQ426[化学工程] O643.36[理学—物理化学]