改性12CaO·7Al2O3表面羟基阴离子发射的机理特征。

Mechanistic features for hydroxyl anion emission from the modified 12CaO.7Al2O3 surface.

作者信息

Li Jiang, Huang Fan, Wang Lian, Wang Zhaoxiang, Yu Shuqin, Torimoto Youshifumi, Sadakata Masayoshi, Li Quanxin

机构信息

Department of Chemical Physics, Lab of Biomass Clean Energy, University of Science & Technology of China, Hefei, Anhui, 230026, P.R. China.

出版信息

J Phys Chem B. 2005 Aug 4;109(30):14599-603. doi: 10.1021/jp0517697.

DOI:10.1021/jp0517697

PMID:16852841

Abstract

OH(-), O(-), and H(-) emissions from the Ca(24)Al(28)O(64).4(OH(-)) (defined as C12A7-OH(-)) surface were investigated by time-of-flight (TOF) spectrometry. The emission intensities were sensitive to surface temperature and extraction field. The apparent activation energies of anions decreased with the increase of applied extraction field. At an extraction field of 800 V/cm, the emission ratio of OH(-) to total anions is 0.98-0.65 in the temperature range of 870-1075 K. The OH(-) emission from C12A7-OH(-) was described by the following kinetic processes: the OH(-) anions in the cages migrated onto the sample surface by field enhanced thermal diffusion, and then desorbed to form the gas-phase anions of OH(-). The O(-) emission originated from the dissociation of O(2-) and OH(-). Similarly, H(-) emission was also attributed to the dissociation of OH(-) on the C12A7-OH(-) surface.

摘要

通过飞行时间（TOF）光谱法研究了Ca(24)Al(28)O(64).4(OH(-))（定义为C12A7-OH(-)）表面的OH(-)、O(-)和H(-)发射。发射强度对表面温度和提取场敏感。阴离子的表观活化能随着施加提取场的增加而降低。在800 V/cm的提取场下，在870-1075 K的温度范围内，OH(-)与总阴离子的发射比为0.98-0.65。C12A7-OH(-)的OH(-)发射由以下动力学过程描述：笼中的OH(-)阴离子通过场增强热扩散迁移到样品表面，然后解吸形成气相的OH(-)阴离子。O(-)发射源于O(2-)和OH(-)的解离。同样，H(-)发射也归因于C12A7-OH(-)表面上OH(-)的解离。