氮化碳负载钯催化剂催化苯酚加氢制环己酮

为了开发苯酚加氢制环己酮高效催化剂，将脲在550 ℃高温聚合，制备了片层状氮化碳催化剂载体g-CN；负载钯纳米粒子后，得到Pd/g-CN催化剂。采用红外光谱、X射线粉末衍射、透射电镜和X射线光电子能谱对催化剂进行表征。将Pd/g-CN催化剂用于催化苯酚水相加氢，考察了不同载体和反应温度对催化性能的影响，并对催化剂重复使用性能进行研究。结果表明，载体g-CN含有大量的含N基团，能有效稳定金属纳米粒子，从而获得粒径较小、分散较好的Pd纳米粒子；同时，g-CN具有较强碱性，有利于苯酚的吸附，可提高苯酚的反应速率和环己酮选择性。采用负载Pd质量分数2%的Pd/g-CN催化剂，在反应温度80 ℃、反应压力0.1 MPa、n(Pd)∶n(苯酚)=0.02、苯酚1 mmol、水3 mL和反应时间3 h条件下，苯酚可完全转化，环己酮选择性高达99%。Pd/g-CN催化剂制备工艺简单，原料价廉，催化性能优异。

Palladium supported carbon nitride catalyst for catalytic hydrogenation of phenol to cyclohexanone

In order to develop the catalyst for phenol hydrogenation to cyclohexanone, the carbon nitride catalyst carder g-CN with layer structure was prepared by high temperature polymerization of urea at 550℃ , and Pd/g-CN catalyst was obtained after loading of Pd nanoparticles. The catalyst was character- ized by infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy and X-ray photo- electron spectroscopy. Pd/g-CN catalyst was used for the catalytic hydrogenation of phenol. The effects of supports and reaction temperatures on catalytic performance and the reusability of the catalyst were inves- tigated. The results showed that g-CN carrier with a lot of nitrogen containing groups could not only stabi- lize Pd nanoparticles to obtained well dispersed Pd nanoparticles effectively, but also be beneficial to adsorption of phenol due to its strong alkalinity, so the reaction rate of phenol and the selectivity to cyclohex- anone could be enhanced. Under the condition of reaction temperature 80 ℃, reaction pressure 0. 1 MPa, n （Pd） ： n （phenol） = 0.02, phenol amount 1 mmol, solvent water dosage 3 mL, reaction time 3 h, and 2wt% Pd/g-CN as the catalyst, phenol could be converted completely and the selectivity to cyclohexanone reached 99%. Pd/g-CN catalyst had the advantages of simple preparation method, cheap raw materials and excellent catalytic performance.