Pd-Pt/HZSM-5催化剂的制备及催化低浓度甲烷燃烧性能  

Preparation of Pd-Pt/HZSM-5 catalysts and their catalytic performance for low-concentration methane combustion

作　　者：高倩文 王晓波 邓存宝 张新琦 王雪峰 王荀 GAO Qianwen;WANG Xiaobo;DENG Cunbao;ZHANG Xinqi;WANG Xuefeng;WANG Xun(College of Safety and Emergency Management Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,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

出　　处：《精细化工》2024年第8期1788-1794,1803,共8页Fine Chemicals

基　　金：国家青年科学基金项目(52004177)。

摘　　要：以Pt(NH_(3))_(4)Cl_(2)和Pd(NO_(3))2·2H_(2)O为Pt和Pd前驱体盐,HZSM-5分子筛为载体,采用浸渍法制备了Pd-Pt/HZSM-5催化剂,将不同硅铝比[n(SiO_(2))∶n(Al_(2)O_(3))=38∶1、200∶1、800∶1]的Pd-Pt/HZSM-5催化剂分别命名为Pd-Pt/HZSM-5(38)、Pd-Pt/HZSM-5(200)、Pd-Pt/HZSM-5(800)。采用XRD、SEM、TEM、Raman、XPS、CO_(2)-TPD和NH3-TPD对催化剂进行了表征,并通过固定床反应器测试了其催化低浓度(体积分数为0.5%)甲烷燃烧反应的活性。结果表明,Pd-Pt/HZSM-5(38)具有较小的Pd/Pt颗粒尺寸(6.3 nm),最多的Pd O结晶、活性Pd/Pt物种和酸性位点,最高的n(Pd^(0))∶n(Pd^(2+))及最高的Pt质量分数(0.19%),其表现出最好的催化性能。与Pd-Pt/HZSM-5(800)和Pd-Pt/HZSM-5(200)相比,Pd-Pt/HZSM-5(38)催化低浓度甲烷燃烧的起燃温度(T_(10))分别降低了27.54和30.92℃,完全转化温度(T_(90))分别降低了3.38和17.51℃。Pd-Pt/HZSM-5(38)在360℃下可稳定运行150 h内,甲烷转化率在99.6%以上,活性无明显下降。Pd-Pt/HZSM-5 catalysts were prepared by impregnation method using Pt(NH_(3))_(4)Cl_(2) and Pd(NO_(3))2·2H_(2)O as precursor salts of Pt as well as Pd,and HZSM-5 molecular sieves as carriers.The Pd-Pt/HZSM-5 catalysts with different Si/Al ratios[n(SiO_(2))∶n(Al_(2)O_(3))=38∶1,200∶1,800∶1],named as Pd-Pt/HZSM-5(38),Pd-Pt/HZSM-5(200)and Pd-Pt/HZSM-5(800),respectively,were characterized by XRD,SEM,TEM,Raman,XPS,CO_(2)-TPD and NH3-TPD,and evaluated on their catalytic activity for low-concentration(0.5%volume fraction)methane combustion by a fixed bed reactor.The results showed that Pd-Pt/HZSM-5(38)exhibited the best catalytic performance with smaller Pd/Pt particle size(6.3 nm),the largest number of PdO crystals,active Pd/Pt species and acidic sites,the highest n(Pd^(0))∶n(Pd^(2+))and the highest Pt mass fraction(0.19%).Compared with those of Pd-Pt/HZSM-5(800)and Pd-Pt/HZSM-5(200),the ignition temperature(T_(10))of low-concentration methane combustion catalyzed by Pd-Pt/HZSM-5(38)decreased by 27.54 and 30.92℃,respectively,while the total conversion temperature(T_(90))was reduced by 3.38 and 17.51℃,respectively.Moreover,Pd-Pt/HZSM-5(38)could run stably at 360℃for 150 h with no significant decrease in the activity,and the methane conversion rate was maintained above 99.6%.

关 键 词：低浓度甲烷 催化剂 HZSM-5 催化燃烧 双金属 

分 类 号：TQ426[化学工程]