Preparation of nanocrystalline Na_2ZrO_3 for high-temperature CO_2 acceptors:chemistry and mechanism  

作　　者：Tiejun Zhao Magnus Rφnning De Chen 

机构地区：[1]Department of Chemical Engineering,Norwegian University of Science and Technology,N-7491 Trondheim,Norway [2]Low-Carbon Energy Conversion Center,Shanghai Advanced Research Institute,Chinese Academy of Sciences

出　　处：《Journal of Energy Chemistry》2013年第3期387-393,共7页能源化学（英文版）

基　　金：supported by the Research Council of Norway

摘　　要：Nanocrystalline Na2ZrO3 was demonstrated as a promising acceptor for CO2 capture at elevated temperatures. The mechanism of nanocrystalline Na2ZrO3 formation from the soft-chemistry route is elucidated by varying precursors, preparation methods, and calciantion temperatures, combining detailed characterizations by X-ray diffraction （XRD） and scanning electron microscope （SEM） at different steps in the process. The results revealed that the drying method such as spraying drying and simple evaporation-drying did not influence the final product prop- erties. However both Na and Zr precursors had remarkable influences on the Na2ZrO3 formation. The solid reaction of Na intermediate and nanocrystalline ZrO2 in the calcination was identified as the key step for the Na2ZrO3 formation, where the formation of molten phase Na intermediate was found to be crucial to facilitate the solid reaction. We provided principles for rational design of the chemistry for the Na2ZrO3 formation where the formation of Na intermediate with low melting points is essential. Pure nanocrystalline Na2ZrO3 can be synthesized from a mixture containing sodium nitrate and zirconoxy citrate via the formation of NaNO3 with low melting point. However, it is not possible to form pure nanocrystalline Na2ZrO3 at relatively low temperatures from the mixtures of NaAc/ZrO（NO3）2 or NaCA/ZrOC12 due to the formation of Na2CO3 and NaC1 with high melting points.Nanocrystalline Na2ZrO3 was demonstrated as a promising acceptor for CO2 capture at elevated temperatures. The mechanism of nanocrystalline Na2ZrO3 formation from the soft-chemistry route is elucidated by varying precursors, preparation methods, and calciantion temperatures, combining detailed characterizations by X-ray diffraction （XRD） and scanning electron microscope （SEM） at different steps in the process. The results revealed that the drying method such as spraying drying and simple evaporation-drying did not influence the final product prop- erties. However both Na and Zr precursors had remarkable influences on the Na2ZrO3 formation. The solid reaction of Na intermediate and nanocrystalline ZrO2 in the calcination was identified as the key step for the Na2ZrO3 formation, where the formation of molten phase Na intermediate was found to be crucial to facilitate the solid reaction. We provided principles for rational design of the chemistry for the Na2ZrO3 formation where the formation of Na intermediate with low melting points is essential. Pure nanocrystalline Na2ZrO3 can be synthesized from a mixture containing sodium nitrate and zirconoxy citrate via the formation of NaNO3 with low melting point. However, it is not possible to form pure nanocrystalline Na2ZrO3 at relatively low temperatures from the mixtures of NaAc/ZrO（NO3）2 or NaCA/ZrOC12 due to the formation of Na2CO3 and NaC1 with high melting points.

关 键 词：Na2ZrO3 CO2 capture spray drying CALCINATIONS nanocrystal 

分 类 号：TB383.1[一般工业技术—材料科学与工程]