Effects of support materials and silver loading on catalytic ammonia combustion properties
Effects of support materials and silver loading on catalytic ammonia combustion properties
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DOI：
10.1016/j.cattod.2017.08.010
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发表时间：
2018-04-01
期刊：
影响因子：
5.3
通讯作者：
Machida, Masato
中科院分区：
文献类型：
--
作者：
Hinokuma, Satoshi;Shimanoe, Hiroki;Machida, Masato
在这项研究中，研究了载体材料和银（Ag）负载量对氨催化燃烧性能的影响。在负载于各种金属氧化物材料上的银中，Ag/Al₂O₃表现出高的氨催化燃烧活性和高的N₂（低N₂O·NO）选择性。燃烧活性与通过O₂ - H₂滴定技术估算的银分散度密切相关。因此，载体上高度分散的银纳米粒子在氨的低温起燃中起着关键作用，这意味着载体材料对银的分散度有显著影响。尽管负载量更高的Ag/Al₂O₃往往表现出更高的燃烧活性，但发现最佳的银负载量约为10 wt.%。在最佳银负载浓度下，Ag/Al₂O₃在氨催化燃烧反应中表现良好。通过透射电子显微镜、X射线吸收精细结构和气体吸附技术研究了催化剂的局部结构。在900℃的氨燃烧反应后，由于金属银纳米粒子的烧结和表面积的减小，Ag/Al₂O₃略有失活。
In this research, the effects of support materials and silver (Ag) loading on catalytic NH3 combustion properties were studied. Among the Ag supported on various metal-oxide materials, Ag/Al2O3 exhibited high catalytic NH3 combustion activity and high N-2 (low N2O center dot NO) selectivity. The combustion activity is closely associated with the Ag dispersion which is estimated using the O-2-H-2 titration technique. Thus, highly dispersed Ag nanoparticles on supports play a crucial role in the low-temperature light-off of NH3, implying that the support materials significantly affect the Ag dispersion. Although Ag/Al2O3 with higher amounts of Ag loading tended to exhibit higher combustion activity, the optimum Ag loading was found to be approximately 10 wt.%. At the optimum Ag loading concentration, Ag/Al2O3 performed well during the catalytic NH3 combustion reaction. The local structures of the catalysts were investigated via transmission electron microscopy, X-ray absorption fine structure and gas adsorption techniques. After an NH3 combustion reaction at a temperature of 900 degrees C, Ag/Al2O3 slightly deactivated because of the sintering of metallic Ag nanoparticles and the decreased surface area.