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负载型贵金属纳米催化剂中的金属纳米粒子易发生团聚或流失,因此提高金属活性组分的分散性和稳定性很重要。我们报道了一种制备高分散钯纳米催化剂的方法,通过浸泡法将氯钯酸前驱体负载到苯并噁嗪聚合物上,再经过惰性气氛一步热解得到纳米炭球担载钯催化剂.催化剂性能通过温和条件下苯甲醇氧化反应进行评价.经过500℃热处理制备的催化剂,从TEM图可以看出Pd纳米粒子均匀分散在载体上,尺寸大小约为3 nm,这是由于载体和钯活性组分的配位作用有利于提高钯纳米粒子的分散性和稳定性.通过调控金属负载量及负载时间,尽可能地实现活性组分分布在载体外表面,制备的催化剂上最高TOF为690 h-1.此催化剂同时具有较好的循环稳定性,失活后的催化剂经过200℃焙烧即可实现再生.
It is very important to increase the dispersion and stability of the metal active component because the metal nanoparticles in the supported noble metal nano-catalyst tend to agglomerate or drain. We reported a method for preparing highly dispersed palladium nanocatalysts by loading a precursor of chloropalladate onto a benzoxazine polymer by an immersion method and then carrying out a one-step pyrolysis in an inert atmosphere to obtain a nanocarbon-supported palladium catalyst. The performance of the catalyst was evaluated by the oxidation of benzyl alcohol under mild conditions.After 500 ℃ heat treatment, the Pd nanoparticles were uniformly dispersed on the support and the size was about 3 nm, which was due to the carrier and palladium activity The coordinating action of the catalyst is conducive to improving the dispersibility and stability of the palladium nanoparticles.Metal loading and loading time can be controlled so that the active components are distributed on the outer surface of the carrier as much as possible.The maximum TOF of the prepared catalyst is 690 h- 1. This catalyst has good cycle stability at the same time. After deactivation, the catalyst can be regenerated by calcination at 200 ℃.