摘要
从Pd纳米粒子出发制备具有核壳结构的Pd@SiO_(2)纳米粒子,并将其负载于不同形貌Al_(2)O_(3)载体上,制备出具有良好CO催化氧化活性的催化剂。以纳米球形Al_(2)O_(3)为载体时,Pd@SiO_(2)/Al_(2)O_(3)催化剂活性优于无核壳结构的Pd/Al_(2)O_(3)催化剂。将纳米Pd@SiO_(2)负载到球形和菱形Al_(2)O_(3)上,制备出Pd@SiO_(2)/Al_(2)O_(3)催化剂。结果表明:具有较大比表面积的Al_(2)O_(3)载体(球形)有利于Pd@SiO_(2)的分散,且SiO_(2)层可以抑制Pd粒子的团聚,能在一定程度上改善催化活性。而较小比表面积的载体(菱形)上出现了Pd@SiO_(2)的团聚,表现出较低的CO氧化活性,但在降低负载量后,CO氧化活性明显提高。该结果为推动新型热稳定、高效纳米三效催化剂的研发具有一定的启示意义。
Pd@SiO_(2) nanoparticles with core-shell structure were prepared from Pd nanoparticles and supported on Al_(2)O_(3) supports with different morphologies to prepare catalysts with good catalytic oxidation activity of CO.The activity of Pd@SiO_(2)/Al_(2)O_(3) catalyst is better than that of Pd/Al_(2)O_(3) catalyst without core and shell structure when nano-spherical Al_(2)O_(3) is used as support.The Pd@SiO_(2)/Al_(2)O_(3) catalysts were prepared by loading the Pd@SiO_(2) onto spherical and rhomboid Al_(2)O_(3) catalysts.The results show that the Al_(2)O_(3) support with large specific surface area(spherical)is conducive to the dispersion of Pd@SiO_(2),and the SiO_(2) layer can inhibit the agglomeration of Pd particles,and improve the catalytic activity to a certain extent.On the other hand,the carrier with smaller specific surface area(rhombus)showed the aggregation of Pd@SiO_(2),which showed a lower CO oxidation activity,but the CO oxidation activity was significantly improved after the load was reduced.The results have certain enlightenment significance for promoting the development of new thermal stable and high efficiency nano three-way catalyst.
作者
李双叶
宋丽云
鲍林生
石磊
马利军
訾学红
李坚
LI Shuangye;SONG Liyun;BAO Linsheng;SHI Lei;MA Lijun;ZI Xuehong;LI Jian(Faculty of Environment and Life, Beijing, 100020)
出处
《合成化学》
CAS
2022年第7期542-549,共8页
Chinese Journal of Synthetic Chemistry
基金
国家重点研发计划(2017YFC0210302)。
关键词
核壳结构
CO氧化
钯
二氧化硅
热稳定性
core-shell structure
oxidation of CO
Pd
SiO_(2)
thermal stability
