摘要
以碳纳米管（CNTs）为模板,采用液相沉积-水热法制备了管状纳米氧化铈（Ce O2-NT）.利用X射线衍射、透射电镜和N2等温吸附-脱附技术对其结构进行了表征,所得Ce O2-NT外径∽25 nm,长度大于300 nm,管壁由粒径4–9 nm的Ce O2晶粒组成,比表面积为108.8 m2/g.以其为载体制备了Pd-O/Ce O2-NT催化剂,程序升温还原结果发现,该催化剂表面氧在低温下即可被还原,具有较高的活性.将Pd-O/Ce O2-NT用于催化苯酚氧化羰基化反应,催化剂活性和碳酸二苯酯（DPC）选择性均高于零维CeO 2负载的Pd-O/Ce O2-P催化剂.在优化的条件下,苯酚转化率为67.7%,DPC选择性为93.3%.但该催化剂再次使用时活性下降明显,这是由于Pd-O/Ce O2-NT的管状结构在反应过程中被破坏,并且活性组分Pd流失所致.
CeO 2 nanotubes（CeO 2-NT） were synthesized using carbon nanotubes as template by a liquid phase deposition and hydrothermal method. X-ray diffraction, transmission electron microscopy, and N2adsorption-desorption were used to characterize the CeO 2-NT. The wall of CeO 2-NT was composed of small interconnected nanocrystallites ranging from 4 to 9 nm in size. The specific surface area of CeO 2-NT was 108.8 m2/g with an outer diameter of 25 nm and length 300 nm. Supported Pd catalyst, Pd-O/CeO 2-NT, was prepared using CeO 2-NT as the support. Temperature-programmed reduction analysis showed that the surface oxygen on Pd-O/CeO 2-NT could be reduced at low temperature, therefore it showed high activity in the reaction. Pd-O/CeO 2-NT was used as the catalyst for the oxidative carbonylation of phenol. It has better activity and DPC selectivity than Pd-O/CeO 2-P, which was prepared by supporting Pd on zero dimensional CeO 2 particles. Under the optimized conditions, phenol conversion was 67.7% with 93.3% DPC selectivity with Pd-O/CeO 2-NT. However, its catalytic activity decreased when the catalyst was used for the second time. This was attributed to the destruction of the tubular structure of Pd-O/CeO 2-NT and Pd leaching during the reaction.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第7期1142-1154,共13页
基金
supported by the National Natural Science Foundation of China(21236001
21176056
21106031)
the Programme for 100 Excellent Talents in University of Hebei Province(II)(BR2-208)
the Natural Science Foundation of Hebei Province(B2015202228)~~
关键词
碳酸二苯酯
氧化羰基化
氧化铈纳米管
钯催化剂
程序升温还原
表面氧
Diphenyl carbonate Oxidative carbonylation Ceria nanotube Palladium catalyst Temperature-programmed reduction Surface oxygen
