碳纳米管负载Pd/SnO_2催化剂的制备及其催化邻氯硝基苯加氢性能

Synthesis of Carbon Nanotubes-Supported Pd/SnO_2 for the Hydrogenation of ortho-Chloronitrobenzene

采用化学还原法制备了不同Sn/Pd摩尔比的碳纳米管(CNTs)负载Pd/SnO2催化剂,并将该催化剂用于邻氯硝基苯(o-CNB)的选择加氢反应.采用透射电镜、X射线衍射和电感耦合等离子体技术对所制备的Pd/SnO2/CNTs催化剂进行了表征.结果表明,Sn/Pd摩尔比对该催化剂的邻氯硝基苯选择加氢反应性能影响显著.当Sn/Pd摩尔比为11时,催化剂的活性最高,在常压,60oC反应60min,o-CNB转化率为96%.该催化剂还具有高的邻氯苯胺(o-CAN)选择性,o-CNB转化率达到100%时,脱氯副产物苯胺选择性小于5%.在相同条件下,浸渍法制备的2.4%Pd/CNTs催化剂上脱氯副反应严重,当o-CNB完全转化时,o-CAN选择性只有22%,副产物苯胺选择性则高达78%.

Carbon nanotubes （CNTs）-supported Pd/Sn02 catalysts with different Sn/Pd molar ratios were prepared by the chemical reduction method, and their catalytic activity was tested using ortho-chloronitrobenzene （o-CNB） hydrogenation as a probe reaction. The as-made Pd/SnO2/CNTs catalysts were characterized by transmission electron microscopy, X-ray diffraction, and inductively coupled plasma techniques. The results show that the catalytic performance of Pd/SnO2/CNTs is greatly affected by the Sn/Pd molar ratio. When the Sn/Pd molar ratio is 11, the Pd/SnO2/CNTs catalyst exhibits the highest activity with 96% conversion of o-CNB at 0.1 MPa and 60℃ in 60 min. Moreover, the Pd/SnO2/CNTs catalysts show very good ortho-chloroaniline （o-CAN） selectivity, evidenced by the fact that the selectivity for by-product aniline is less than 5% when the conversion of o-CNB is 100%. For the 2.4% Pd/CNTs catalyst prepared by impregnation, under the identical conditions, the selectivity for o-CAN is only 22% when the o-CNB conversion is 100%.