Water Adsorption and Its Effect on the Stability of Low Index Stoichiometric and Reduced Surfaces of Ceria
Water Adsorption and Its Effect on the Stability of Low Index Stoichiometric and Reduced Surfaces of Ceria
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DOI：
10.1021/jp300576b
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发表时间：
2012-03
影响因子：
3.7
通讯作者：
M. Molinari;Stephen C. Parker;D. Sayle;M. S. Islam
中科院分区：
文献类型：
--
作者：
M. Molinari;Stephen C. Parker;D. Sayle;M. S. Islam
水对二氧化铈氧化还原性质的影响是其广泛开发的关键，跨越各种应用。基于DFT-GGA+U的从头计算模拟技术被用来研究水-二氧化铈体系，包括水的缔合（H2O）和解离（−OH）吸附/脱附以及在水蒸气存在下在不同水覆盖率的二氧化铈的化学计量和还原低指数表面上形成氧空位。我们的计算解决了有关CeO 2 {111}上的水吸附的争议，并报道了CeO 2 {110}和{100}表面的新结果。模拟结果显示，化学计量表面上的解离（−OH）吸附水具有很强的水覆盖度依赖性，在高覆盖度时逐渐不稳定，而缔合（H2O）吸附由于吸附分子之间的相互作用较弱而对覆盖度依赖性较弱。吸附几何构型分析表明，表面铈原子的吸附是由于表面铈原子的吸附而引起的。
The influence of water on the redox properties of ceria is pivotal to its widespread exploitation spanning a variety of applications. Ab initio simulation techniques based on DFT-GGA+U are used to investigate the water–ceria system including associative (H2O) and dissociative (−OH) adsorption/desorption of water and the formation of oxygen vacancies in the presence of water vapor on the stoichiometric and reduced low index surfaces of ceria at different water coverages. Our calculations address the controversy concerning the adsorption of water on the CeO2{111}, and new results are reported for the CeO2{110} and {100} surfaces. The simulations reveal strong water coverage dependence for dissociatively (−OH) adsorbed water on stoichiometric surfaces which becomes progressively destabilized at high coverage, while associative (H2O) adsorption depends weakly on the coverage due to weaker interactions between the adsorbed molecules. Analysis of the adsorption geometries suggests that the surface cerium atom c...