高分散Co_(3)O_(4)对钙钛矿类LaCoO_(3)低浓度甲烷催化燃烧性能的影响  

Effect of highly dispersed Co_(3)O_(4) on the catalytic performance of LaCoO_(3) perovskite in the combustion of lean methane

作　　者：陈雪 王雪峰 王荀 邓存宝 曹敏敏 CHEN Xue;WANG Xue-feng;WANG Xun;DENG Cun-bao;CAO Min-min(School of Engineering for Safety and Emergency Management,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Coking Coal Group Co.,LTD.,Taiyuan 030024,China)

机构地区：[1]太原理工大学安全与应急管理工程学院,山西太原030024 [2]山西焦煤集团有限责任公司,山西太原030024

出　　处：《燃料化学学报（中英文）》2023年第3期367-375,共9页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金联合基金(U1810206);国家自然科学基金面上项目(51774172)资助。

摘　　要：本研究采用溶胶凝胶法,通过调变镧钴比合成了一种纳米新型钙钛矿类催化剂。利用物理吸附、ICP、XRD、H_(2)-TPR、O_(2)-TPD和XPS等技术对催化剂进行了表征,并对其在乏风甲烷氧化燃烧中的催化性能进行了研究。结果表明,高分散性的Co_(3)O_(4)纳米颗粒有利于甲烷的低温活化,且催化剂中镧钴钙钛矿体相可提供大量的晶格氧,促进高温下甲烷的催化燃烧速率和催化剂的高温稳定性。通过调变镧钴比例,可有效调变催化剂中Co_(3)O_(4)纳米颗粒的分散状态,进而实现催化剂低温活性和高温稳定性的有效统一。当La/Co比为0.9时,在空速为30000 mL/(g_(cat)·h)的条件下,La_(0.9)CoO_(3)钙钛矿催化剂的甲烷起燃温度为382℃;稳定运行72 h后,甲烷转化率保持在95%以上。这些结果为今后开发低成本、高活性和高稳定性的甲烷燃烧催化剂提供了参考。In this work,a series of nano LaCoO_(3)perovskite catalysts were effectively synthesized by a sol-gel method through modulating the La/Co molar ratio.These catalysts were characterized by ICP,XRD,N2sorption,H_(2)-TPR,O_(2)-TPD,and XPS,and their catalytic performance in the lean methane combustion were then investigated.The results indicate that highly dispersed Co_(3)O_(4)nanoparticles on the LaCoO_(3)perovskite catalysts are beneficial to the activation of CH_(4)at a low temperature,while the La-Co-perovskite bulk phase can provide a large amount of lattice oxygen,which can enhance the reaction rate of methane combustion and the catalytic stability at a high temperature.Through altering the La/Co molar ratio,the dispersion of Co_(3)O_(4)nanoparticles in the La-Co-perovskite catalyst can be effectively modulated,to achieve the concurrence of low-temperature activity and high-temperature stability in the lean methane combustion.In particular,the La_(0.9)CoO_(3)perovskite catalyst with a La/Co molar ratio of0.9 exhibits excellent performance in lean methane combustion,with a light-off temperature of 382℃at a space velocity of 30000 mL/(g_(cat)·h),the light-off temperature of methane is 382℃,and the methane conversion rate is still maintained above 95%after 72 h of stable operation,indicating that the highly dispersed Co_(3)O_(4)nanoparticles were beneficial to the low-temperature activation of CH_(4),and the lanthanum-cobalt-perovskite bulk phase in the catalyst could provide a large amount of lattice oxygen,which promotes the catalytic combustion rate of CH_(4)and the hightemperature stability of the catalyst under high-temperature conditions.By modulating the lanthanum-cobalt ratio,the dispersion state of Co_(3)O_(4)nanoparticles in the catalyst can be effectively modulated,and then the effective unification of low-temperature activity and high-temperature stability of the catalyst can be achieved,which guides the future development of low-cost,high-activity and high-stability catalysts for methane catalytic

关 键 词：甲烷催化燃烧 LaCoO_(3) Co_(3)O_(4) 高分散 晶格氧 

分 类 号：X959[环境科学与工程—安全科学]