Sinha V, Sun D, Meijer E J, Vlugt T J H, Bieberle-Hütter A
Electrochemical Materials and Interfaces, Dutch Institute for Fundamental Energy Research (DIFFER), de Zaale 20, Eindhoven, 5612 AJ, The Netherlands.
Amsterdam Center for Multiscale Modelling, van' t Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.
Faraday Discuss. 2021 May 1;229:89-107. doi: 10.1039/c9fd00140a. Epub 2021 Mar 18.
Photoelectrochemical (PEC) splitting of water to make hydrogen is a promising clean-energy technology. The oxygen evolution reaction (OER) largely determines the energy efficiency in PEC water-splitting. Hematite, which is a cheap and sustainable semiconductor material with excellent chemical properties, a favourable band gap (2.1 eV) and composed of earth abundant elements is a suitable model photoanode material for studying OER. To understand the design of energy efficient anodes, it is highly desirable to have mechanistic insight into OER at an atomistic level which can be directly connected to experimentally measured quantities. We present a multiscale computational model of OER which connects the thermodynamics and kinetics of elementary charge transfer reactions in OER to kinetics of OER at laboratory length and time scales. We couple density functional theory (DFT) and DFT based molecular dynamics (DFT-MD) simulations with solvent effects at an atomistic level with kinetic Monte Carlo (kMC) simulations at a coarse-grained level in our multiscale model. The time and applied bias potential dependent surface coverage, which are experimentally not known, and the O evolution rate during OER at the hematite-water interface are calculated by the multiscale model. Furthermore, the multiscale model demonstrates the effect of explicitly modelling the interaction of water with the electrode surface via direct adsorption.
光电化学（PEC）水分解制氢是一项很有前景的清洁能源技术。析氧反应（OER）在很大程度上决定了PEC水分解的能量效率。赤铁矿是一种廉价且可持续的半导体材料，具有优异的化学性质、合适的带隙（2.1电子伏特）且由地球上储量丰富的元素组成，是研究OER的合适的光阳极材料模型。为了理解高效阳极的设计，非常需要在原子水平上对OER有机理上的深入了解，这可以直接与实验测量的量联系起来。我们提出了一个OER的多尺度计算模型，该模型将OER中基本电荷转移反应的热力学和动力学与实验室长度和时间尺度上的OER动力学联系起来。在我们的多尺度模型中，我们将密度泛函理论（DFT）和基于DFT的分子动力学（DFT-MD）模拟与原子水平上的溶剂效应以及粗粒度水平上的动力学蒙特卡罗（kMC）模拟相结合。通过多尺度模型计算了实验上未知的与时间和外加偏置电势相关的表面覆盖率以及赤铁矿-水界面OER过程中的氧析出速率。此外，该多尺度模型还展示了通过直接吸附对水与电极表面相互作用进行显式建模的效果。
