纳米氧化物上担载金属催化剂加氢脱卤性能研究

【作者】 沈常美；

【导师】 菅盘铭；

【作者基本信息】 扬州大学 ， 物理化学， 2005， 硕士

【摘要】 一、催化剂的制备及表征 采用溶胶凝胶法制备得Zr（OH）₄凝胶。凝胶采用乙醇进行醇化处理,然后进行烘干、焙烧得ZrO₂纳米载体,载体颗粒粒径均匀,大小为20nm。该方法很好的解决了从Zr（OH）₄凝胶到ZrO₂的热变化过程中聚集引起的比表面积的损失问题。以ZrO₂为载体采用浸渍法分别负载不同含量的金属Ni,并以低含量的Pd、Pt等贵金属对此催化剂进行改性,制得Pd-Ni/ZrO₂、Pt-Ni/ZrO₂催化剂。通过IR、BET、XRD、TEM、SEM等手段对催化剂进行了表征。并以氯苯、二氯苯等物质的脱氯反应考察了催化剂的活性。实验发现,贵金属Pd对催化剂的改性效果远比贵金属Pt优越,且催化剂中金属Ni的含量对催化剂活性有比较明显的影响。所制得的催化剂在空气中能稳定存放,不易失活,并且在催化剂使用过程中仍保持结构完整。Pd-Ni/ZrO₂与Pd/C纤维、Raney-Ni、Pt-Sn/Al₂O₃工业中常用催化剂相比具有更好的脱氯加氢效果。 二、氯苯加氢脱卤性能研究 采用负载法制备了一系列纳米ZrO₂担载金属Ni、Pd催化剂,通过XRD、TEM、SEM等技术对催化剂进行了表征,并以氯苯的加氢脱氯为探针反应,考察了催化剂的加氢脱氯性能。同时考察了反应温度、反应体系碱的类型、碱的用量、催化剂中镍含量等因素对催化反应活性的影响。实验表明,80℃、NaOH和氯苯的摩尔比为1∶1的反应条件下,在Ni质量分数为10%的Pd-Ni/ZrO₂催化剂的作用下9h后氯苯的转化率可达到100%。 三、二氯苯加氢脱卤性能研究更多还原

【Abstract】 1. Preparation and characterization of catalystsZr（OH）₄ gel was prepared by sol-gel method and the gel was alcoholized by ethanol.. Then Zr（OH）₄ gel was dried and calcined to get Z1O₂ nanometer scale particles which sizes were about 20nm. This method solved the reduction of the catalysts surface area during the heating process from Zr（OH）4 to ZrO₂. A series of different amount nickel metal catalysts supported on zirconia were prepared. And a little amount metal Pd or Pt were used to optimize the activity of the catalysts. The samples were characterized using IR, BET, XRD, TEM, SEM method. The activities of catalysts were studied by the reaction of chlorobenzene hydrodechlorination and dichlorobenzene hydrodechlorination. The experimental results showed that the catalysts improved by metal Pd had the higher activity than the catalysts improved by metal Pt. The catalysts we made had high stability in the air and maintained the configuration of catalysts during the reaction process. Pd-Ni/ZrO₂ catalysts had better activity than other catalysts such as Pd/C, Raney-Ni and Pt-Sn/Al₂O₃, to the reaction of the hydrodechlorination.2. Study the activity of the catalysts by the reaction of chlorobenzene hydrodechlorinationA series of palladium-nickel catalysts supported on zirconia were prepared. The catalysts samples were characterized by XRD, BET, TEM, SEM methods. The activity of catalysts was studied by the hydrodechlorination of chlorobenzene. The influence of reaction temperature, style of alkali and amounts of alkali and nickel percent in catalysts on activity of catalysts were studied in the article. It was suggested that the conversion of chlorobenzene could be 100% after nine hours at the conditions of 80℃,Pd-Ni/ZrO₂ （Ni 10 wt %） and equal mole of sodium hydroxide and chlorobenzene.3. Study the activity of the catalysts by the reaction of dichlorobenzene hydrodechlorinationBased on the hydrodechlorination of chlorobenzene, one electronegative ion Cl was imported into the benzene loop , the activity of catalysts was studied by the hydrodechlorination of dichlorobenzene. The influence of reaction temperature and amounts of alkali and nickel percent in catalysts on activity of catalysts were studied. On the same conditions, infection of the system pressure was observed. It was suggested that the conversion of chlorobenzene could be 100% after five hours at the conditions of 80℃, Pd-Ni/ZrO₂ （Ni 8 wt %） and equal mole of sodium hydroxide and chlorobenzene. And the reaction velocity in the pressure kettle was faster than the reaction under the normal pressure.更多还原