Interaction of carbon dioxide with the surface of zirconia polymorphs
Interaction of carbon dioxide with the surface of zirconia polymorphs
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DOI：
10.1021/la970856q
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发表时间：
1998-06-13
期刊：
影响因子：
3.9
通讯作者：
Guerrero-Ruiz, A
中科院分区：
文献类型：
--
作者：
Bachiller-Baeza, B;Rodriguez-Ramos, I;Guerrero-Ruiz, A
一系列的氧化锆粉末样品具有不同的结晶相和表面积，无论是在实验室制备或商业获得，已研究了CO2与它们的表面的相互作用。三个互补的技术，如红外光谱，吸附微量热法，和程序升温脱附已被应用到研究的CO2吸附。已经发现，ZrO2的晶体结构决定了其表面上的CO2吸附位点的数量（或密度），从而决定了吸附物种的类型和稳定性。二氧化碳在单斜结构的氧化锆上吸附后，生成碳酸氢盐、单齿碳酸盐和双齿碳酸盐，而在四斜结构的氧化锆上则生成双齿碳酸盐和多齿碳酸盐。虽然在单斜和四斜氧化锆上观察到双齿碳酸盐，但它们出现在不同的频率下，并且它们具有不同的热稳定性，证实了两种氧化锆相的表面具有不同的几何形状。从三种技术应用的结果证实，单斜结构的氧化锆带来了更强的表面吸附网站关于CO2比四斜结构。此外，对于给定的晶体结构，样品的表面积和纹理也影响表面吸附位点的强度。
A series of zirconia powder samples with different crystallographic phases and surface areas, either prepared at the laboratory or obtained commercially, have been studied in relation to the interaction of CO2 with their surfaces. Three complementary techniques such as infrared spectroscopy, adsorption microcalorimetry, and temperature-programmed desorption have been applied to the study of the CO2 adsorption. It has been found that the crystallographic structure of ZrO2 determines the number (or density) of CO2 adsorption sites on its surface, and consequently the type and stability of adsorbed species. Upon carbon dioxide adsorption on zirconia with monoclinic structure, hydrogen carbonates and monodentate and bidentate carbonates are formed, while bidentate and polydentate carbonates are generated on tetragonal zirconia. Although the bidentate carbonates are observed on monoclinic and tetragonal zirconia, they appear at different frequencies and they have different thermal stability, confirming that the surfaces of the two zirconia phases have different geometries. The results from the three techniques applied confirm that the monoclinic structure of zirconia brings about stronger surface adsorption sites concerning CO2 than the tetragonal structure. Moreover, for a given crystallographic structure the surface area and texture of the sample also affect the strength of the surface adsorption sites.