Effect of Copper Loading in Copper-Alumina Aerogels on Three-Way Catalytic Performance
Effect of Copper Loading in Copper-Alumina Aerogels on Three-Way Catalytic Performance
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DOI：
10.1007/s40825-020-00165-z
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发表时间：
2020-06
影响因子：
1.6
通讯作者：
A. Anderson;B. A. Bruno;F. Dilone;M. LaRosa;Thomas Andre;Chris Avanessian;Mary K. Carroll
中科院分区：
文献类型：
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作者：
A. Anderson;B. A. Bruno;F. Dilone;M. LaRosa;Thomas Andre;Chris Avanessian;Mary K. Carroll
气凝胶是一种在高温下稳定的高表面积、低密度、低热质量的纳米多孔材料。这种独特的物理特性组合使它们有望用于三元催化剂系统。它们的高表面积有可能产生更多的活性位点，并改善气固相互作用。它们的高温稳定性可以减少活性位点的扩散/烧结，并允许紧密耦合，这与低热惯性相结合，可能导致点火时间缩短。将各种金属，包括非贵重族金属，纳入气凝胶骨架是相对容易的。通过溶胶-凝胶合成和快速超临界萃取干燥，研制了一系列铜氧化铝（CuAl）气凝胶。将不同数量的铜加入到氧化铝凝胶中，得到的材料中铜的质量为20%到40%。扫描电镜成像显示含铜颗粒分布在材料中，粉末x射线衍射表明铜可能在热处理后处于铝酸铜尖晶石相。这些材料在联合催化气凝胶试验台（UCAT）中进行了测试，该试验台使用模拟废气混合物（含和不含空气），在200至700°C的温度范围内评估催化材料转化NO、hc和CO的性能。UCAT测试结果表明，在气凝胶中加入更多的铜可以将CO转化的起燃温度从350℃降低到225-250℃，hc转化的起燃温度从500℃降低到425 - 450℃（有空气），NO（无空气）的起燃温度从425℃降低到325℃。
Aerogels are high surface area, low density, low thermal mass, nanoporous materials that are stable at high temperatures. This unique combination of physical characteristics makes them promising for use in three-way catalyst systems. Their high surface area has the potential to result in more active sites and improved gas/solid interaction. Their high temperature stability may reduce active site diffusion/sintering and allow for close coupling, which combined with the low thermal inertia may lead to a reduced time to light-off. It is relatively easy to incorporate a variety of metals, including non-precious group metals, into an aerogel backbone. We have developed a series of copper-alumina (CuAl) aerogels via sol-gel synthesis and rapid supercritical extraction drying. Different amounts of copper were incorporated into the alumina gel, resulting in materials with 20% to 40% copper by mass. Scanning electron microscopy imaging shows copper-containing particles distributed in the material, and powder X-ray diffraction indicates that the copper may be in the copper aluminate spinel phase after heat treatment. The materials were tested in the Union Catalytic Aerogel Testbed (UCAT), which evaluates catalytic material performance for conversion of NO, HCs, and CO over a range of temperatures from 200 to 700 °C using a simulated exhaust gas mixture with and without air. UCAT test results indicate that adding more copper to the aerogel lowers the light-off temperature from 350 to 225–250 °C for the conversion of CO and from 500 to 425–450 °C for the conversion of HCs (in the presence of air) and from 425 to 325 °C for NO (without air).