Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obt...Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.展开更多
Integrating the probability screen with the piano-wire screen, the authors developed the QGS2020 type piano-wire probability screen (PWPS), a new screen which has a large capacity, high efficiency, and no blinding. Th...Integrating the probability screen with the piano-wire screen, the authors developed the QGS2020 type piano-wire probability screen (PWPS), a new screen which has a large capacity, high efficiency, and no blinding. The results of the indus trial tests show that this screen is suitable for dry sCreening the fine particles from high-moisture raw coal. This paper describes the operation principles, the structure features and the mechanical model of the QGS2020 type PWPS, and also includes data from industrial tests.展开更多
基金supported by the National Key R&D Program of China(2016YFA0202900)the National Natural Science Foundation of China(21622606)+1 种基金Zhejiang Provincial Natural Science Foundation of China(LR18B060001)the Fundamental Research Funds for the Central Universities~~
文摘Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.
文摘Integrating the probability screen with the piano-wire screen, the authors developed the QGS2020 type piano-wire probability screen (PWPS), a new screen which has a large capacity, high efficiency, and no blinding. The results of the indus trial tests show that this screen is suitable for dry sCreening the fine particles from high-moisture raw coal. This paper describes the operation principles, the structure features and the mechanical model of the QGS2020 type PWPS, and also includes data from industrial tests.
