Accurate Amorphous Silica Surface Models from First-Principles Thermodynamics of Surface Dehydroxylation
Accurate Amorphous Silica Surface Models from First-Principles Thermodynamics of Surface Dehydroxylation
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DOI：
10.1021/la500422p
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发表时间：
2014-05-13
期刊：
影响因子：
3.9
通讯作者：
Johnson, J. Karl
中科院分区：
文献类型：
--
作者：
Ewing, Christopher S.;Bhavsar, Saurabh;Johnson, J. Karl
由于实验数据和计算方法的限制，精确的非晶态材料的原子细节模型一直难以捉摸。我们提出了一种方法来构建在许多工业应用（如催化支撑材料）中遇到的无定形二氧化硅表面的原子模型。我们结合了经典分子建模和密度泛函理论计算来开发具有预测能力的模型。我们的方法提供了精确的表面模型的温度范围内测量的表面去羟基化的热力学。我们发现一个非常小的非晶二氧化硅表面模型可以准确地代表真实表面的物理和化学性质，这一点通过使用硅醇数和类型作为温度函数的宏观测量的直接实验验证得到了证明。除了准确预测实验观察到的硅醇数量和类型的趋势外，该模型还允许对非晶硅表面的去羟基化有新的见解。我们的形式是可转移的，并提供了一种方法来生成其他非晶材料的精确模型。
Accurate atomically detailed models of amorphous materials have been elusive to-date due to limitations in both experimental data and computational methods. We present an approach for constructing atomistic models of amorphous silica surfaces encountered in many industrial applications (such as catalytic support materials). We have used a combination of classical molecular modeling and density functional theory calculations to develop models having predictive capabilities. Our approach provides accurate surface models for a range of temperatures as measured by the thermodynamics of surface dehydroxylation. We find that a surprisingly small model of an amorphous silica surface can accurately represent the physics and chemistry of real surfaces as demonstrated by direct experimental validation using macroscopic measurements of the silanol number and type as a function of temperature. Beyond accurately predicting the experimentally observed trends in silanol numbers and types, the model also allows new insights into the dehydroxylation of amorphous silica surfaces. Our formalism is transferrable and provides an approach to generating accurate models of other amorphous materials.