利用水热老化试验装置开展了催化剂小样的水热老化试验,分析了催化剂在水热老化前后起燃性能的变化规律,利用 X 射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、X 射线衍射(X-ray diffraction,XRD)、N2 吸脱附与透射电子显微镜(transmission electron microscopy,TEM)等测试方法研究了老化温度和老化气氛(水含量)对催化剂活性、表面化学状态及微观结构的影响.试验结果表明,老化温度对催化剂理化特性的影响较大,随着老化温度的提高,催化剂的氧空位含量减少,储氧能力下降,助剂的粒径变大,比表面积变小,孔径变大,催化剂活性降低;老化气氛中水含量的变化对催化剂理化特性的影响较小,当水含量为10%时,催化剂的活性最高,此时催化剂的储氧能力较高,比表面积最大,表明适宜的水热老化有利于催化剂性能提升.
Experimental Study on Effects of Hydrothermal Aging on the Performance of Three-Way Catalytic Converter for a Natural Gas Engine
Hydrothermal aging test of catalyst samples was carried out with hydrothermal aging test device,and the variational laws in the ignition performance of the catalysts before and after hydrothermal aging were analyzed.The effects of aging temperatures and atmospheres(water content)on catalyst activities,surface chemical states and microstructures were studied by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),N2 physical adsorption and transmission electron microscopy(TEM).The results show that the aging temperature has a great influence on the physicochemical properties of the catalyst.With the increase of aging temperature,the oxygen vacancy content of the catalyst decreases,the oxygen storage capacity decreases,the particle size of the auxiliary agent increases,the specific surface area decreases,the pore size increases,and the activity of the catalyst decreases.The change of water content in the aging atmosphere has little influence on the physicochemical properties of the catalyst.When the water content is 10%,the activity of the catalyst is the highest,the oxygen storage capacity of the catalyst is relatively high,and the specific surface area is the largest,which indicates that the appropriate hydrothermal aging is conducive to the improvement of catalyst performance.
three-way catalyst(TWC)aging temperaturewater vapor contentphysical and chemical propertiesmicrostructure
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维普
