Improving TiO 2 Anatase Nanostability Via Interface Segregation: The Role of the Ionic Radius
Improving TiO 2 Anatase Nanostability Via Interface Segregation: The Role of the Ionic Radius
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通过界面偏析提高 TiO 2 锐钛矿纳米稳定性：离子半径的作用
DOI：
10.1021/acs.jpcc.2c04271
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Gouvêa, Douglas
中科院分区：
文献类型：
--
作者：
da Silva, Andre L.;Bettini, Jefferson;Bernardes, Andre A.;Castro, Ricardo H.;Gouvêa, Douglas
二氧化钛纳米粒子在光催化和人工光合作用研究中特别受关注。它们的性质取决于晶体多晶型（例如锐钛矿/金红石相）、比表面积以及吸附 CO2 和 H2O 气体分子的能力等参数。这些参数、表面热化学和应用性能之间存在因果关系。然而，缺乏系统的热力学数据阻碍了更全面的理解以实现控制。这项工作研究了碱土金属掺杂 TiO2 的表面热化学与相关的微米和纳米结构特征之间的关系。掺杂 Mg2+、Ca2+、Sr2+ 或 Ba2+ 的 TiO2 纳米粒子表现出掺杂剂自发偏析到纳米粒子界面，导致表面能逐渐降低（通过吸附微量热法直接测量）。该现象是离子半径的直接函数，导致纳米颗粒的热稳定性提高，防止粗化，稳定锐钛矿多晶型，并增加比表面积。
Titanium dioxide nanoparticles are of particular interest in photocatalysis and artificial photosynthesis studies. Their properties are dependent on parameters such as the crystal polymorph, for example, anatase/rutile phases, the specific surface area, and the capacity to adsorb CO2and H2O gas molecules. A cause-effect relationship exists between those parameters, the surface thermochemistry, and the performance in application. However, the lack of systematic thermodynamic data has hindered a more comprehensive understanding to enable control. This work investigates the relationship between the surface thermochemistry of alkaline earth metals doped TiO2and the associated micro and nanostructural features. TiO2nanoparticles doped with Mg2+, Ca2+, Sr2+, or Ba2+showed spontaneous segregation of dopants to the nanoparticles’ interfaces, leading to incremental surface energy reduction as directly measured by microcalorimetry of adsorption. The phenomenon was a direct function of ionic radius and led to the improved thermal stability of the nanoparticles against coarsening, stabilizing the anatase polymorph, and increasing the specific surface area.