制备高分散Pt纳米催化剂低温催化还原NO  

Preparation of Highly Dispersed Pt Nanoparticles and Catalytic Reduction Performance of NO at Low Temperature

作　　者：徐潇潇[1,2] 李加衡 许小伟 陈敬尧 严新焕[1] 

机构地区：[1]浙江工业大学绿色化学合成技术国家重点实验室培育基地,浙江杭州310014 [2]长兴县质量技术监督检测中心,浙江湖州313100

出　　处：《环境科学与技术》2015年第10期59-63,共5页Environmental Science & Technology

基　　金：国家高技术研究发展计划(863计划)(2013AA065005);浙江省科技创新团队(2011R50017)

摘　　要：文章采用新型的Pt基催化剂制备方法,将高分散的Pt纳米粒子直接吸附到SiO_2载体上即制得了组合型Pt/SiO_2催化剂。研究分析了O_2体积分数、NO/H_2体积比、Pt负载量、空速等操作条件对催化剂脱硝反应活性的影响,并通过XRD、TEM、BET、XPS等对载体及催化剂结构、金属电子价态及Pt纳米颗粒的分布进行了表征。结果表明组合型Pt/SiO_2催化剂在6%O_2体积分数、NO/H_2体积比为1∶4、空速为120000mL/(g·h)时具有较高的NO转化率,温度低至58℃时转化率达到80%,展现了较高的低温催化活性,且在50~200℃的范围内也保持了较高活性,体现了较宽的活性范围。Pt/SiO_2催化剂具有粒径小(4nm),分散性好、比表面积大等特点,且活性组分主要以Pt^0形式分布在载体表面。因此该催化剂具有较高的催化活性。A highly active Pt/SiO2 catalyst was synthesized using propylene carbonate（PC） as dispersant, in which uniformly dispersed Pt nanoparticles were directly loaded on SiO2 support. Catalytic activity tests of the investigated noble metal catalysts were performed under plug flow conditions with different O2 volume fraction,NO/H2 volume ratio,Pt loading and gas hourly space velocity. Pt/SiO2 proved to be the most active catalysts for H2-SCR in terms of NO conversion. The catalysts reached high NOx to N2 conversion（80% conversion） at 58 ℃. The properties of the synthesized catalysts were characterized using X-ray diffraction（XRD）,transmission electron microscopy（TEM）,N2 adsorption-desorption（BrunauerEmmett-Teller（BET） method） and X-ray photoelectron spectroscopy（XPS）. The results showed that Pt/SiO2 crystallites were small（4 nm）with fine dispersion and most of Pt-0 exposure on the support surface. This is the reason why it can reach a high NO conversion.

关 键 词：铂 二氧化硅 NO还原 H2-SCR 

分 类 号：X511[环境科学与工程—环境工程]