School of Electrical, Electronics and Computer Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
Chemistry. 2018 May 23;24(29):7445-7455. doi: 10.1002/chem.201706175. Epub 2018 Apr 30.
Density functional theory calculations are used to study the molecular and dissociative adsorption of water on the (-201) β-Ga O surface. The effect of adsorption of different water-like species on the geometry, binding energies, vibrational spectra and the electronic structure of the surface are discussed. The study shows that although the hydrogen evolution reaction requires a small amount of energy to become energetically favourable, the over potential for activating the oxygen evolution reaction is quite high. The results of our calculations provide insight as to why a high voltage is required in experiments to activate the water-splitting reaction, whereas previous studies of gallium oxide predicted very low activation energies for other energetically more favourable facets. Application of this work to studies of GaN-based chemical sensors with gallium oxide surfaces shows that it is possible to select the gate bias so that the sensors are not influenced by water-splitting reactions. It was also found that in the region where water splitting does not occur, the surface can exist in two states, that is, water or hydroxyl terminated.
密度泛函理论计算被用于研究水在(-201)β-GaO 表面上的分子和离解吸附。讨论了不同水相似物种的吸附对表面几何形状、结合能、振动光谱和电子结构的影响。研究表明，尽管析氢反应需要少量的能量才能变得有利，但激活析氧反应的过电势相当高。我们的计算结果提供了一些见解，说明为什么在实验中需要高电压来激活水分解反应，而先前关于氧化镓的研究预测其他能量更有利的晶面的活化能非常低。将这项工作应用于具有氧化镓表面的 GaN 基化学传感器的研究表明，可以选择栅极偏压，使传感器不受水分解反应的影响。还发现，在水不分解的区域，表面可以存在两种状态，即水分子或羟基终止。
