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
采用氨气还原法制备了 Na Y分子筛负载的 Mo Co/ Y、Mo Ni/ Y双组分氮化物催化剂 ,用 XRD和 EXAFS方法表征了样品的结构 ,并测定了其在 CH4+CO2 重整反应中的活性 .在氧化态时 ,Mo Co/ Y样品中主要存在Co Mo O4和 Co3O4两种物相 ,Mo的...采用氨气还原法制备了 Na Y分子筛负载的 Mo Co/ Y、Mo Ni/ Y双组分氮化物催化剂 ,用 XRD和 EXAFS方法表征了样品的结构 ,并测定了其在 CH4+CO2 重整反应中的活性 .在氧化态时 ,Mo Co/ Y样品中主要存在Co Mo O4和 Co3O4两种物相 ,Mo的配位状态接近于 Co Mo O4,而 Co的配位状态更接近于 Co3O4.Mo Ni/ Y样品中主要有 Ni Mo O4和 Ni O两种物相 ,Mo的配位状态接近于 Ni Mo O4,而 Ni的配位状态可能是 Ni Mo O4和 Ni O两种化合物中 Ni配位状态的平均效果 .Ni- Mo之间的相互作用似乎比 Co- Mo相对较强 .在氮化态时 ,两种样品中Mo的配位状态较为相似 ,但既不同于 Mo O3,也不同于单组分 γ- Mo2 N.Co和 Ni的配位状态都不同于各自在氧化态下的状态 ,且都在相同的位置出现一个新强峰 .这似乎表明 Mo Co和 Mo Ni生成了结构相似的氮化物 .在CH4+CO2 重整反应中 ,氮化态 Mo Co/ Y和 Mo Ni/ Y的活性大大超过非负载单组分 γ- Mo2 N催化剂 .其中 Mo Ni/Y的活性相对更好一些 ,且活性随展开更多
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.
文摘采用氨气还原法制备了 Na Y分子筛负载的 Mo Co/ Y、Mo Ni/ Y双组分氮化物催化剂 ,用 XRD和 EXAFS方法表征了样品的结构 ,并测定了其在 CH4+CO2 重整反应中的活性 .在氧化态时 ,Mo Co/ Y样品中主要存在Co Mo O4和 Co3O4两种物相 ,Mo的配位状态接近于 Co Mo O4,而 Co的配位状态更接近于 Co3O4.Mo Ni/ Y样品中主要有 Ni Mo O4和 Ni O两种物相 ,Mo的配位状态接近于 Ni Mo O4,而 Ni的配位状态可能是 Ni Mo O4和 Ni O两种化合物中 Ni配位状态的平均效果 .Ni- Mo之间的相互作用似乎比 Co- Mo相对较强 .在氮化态时 ,两种样品中Mo的配位状态较为相似 ,但既不同于 Mo O3,也不同于单组分 γ- Mo2 N.Co和 Ni的配位状态都不同于各自在氧化态下的状态 ,且都在相同的位置出现一个新强峰 .这似乎表明 Mo Co和 Mo Ni生成了结构相似的氮化物 .在CH4+CO2 重整反应中 ,氮化态 Mo Co/ Y和 Mo Ni/ Y的活性大大超过非负载单组分 γ- Mo2 N催化剂 .其中 Mo Ni/Y的活性相对更好一些 ,且活性随
