过电位
密度泛函理论
光催化
氧化还原
化学计量学
从头算
半导体
化学
化学物理
分解水
铜
物理化学
电子能带结构
曲面(拓扑)
光催化分解水
热力学
计算化学
材料科学
催化作用
无机化学
凝聚态物理
电化学
物理
几何学
生物化学
光电子学
有机化学
电极
数学
作者
Leah Isseroff Bendavid,Emily A. Carter
摘要
For a photocatalytic reaction to be thermodynamically allowed, a semiconductor's band edges need to be placed appropriately relative to the reaction redox potentials. We apply a recently developed scheme for calculating band edges with density functional theory (DFT)-based methods to Cu2O, evaluating its available thermodynamic overpotential for redox reactions such as water splitting and conversion of CO2 to methanol. Because these calculations are surface dependent, we first study the low-index surfaces of Cu2O using periodic DFT+U theory to characterize and identify the most stable surface, which will be the most catalytically relevant. We employ various techniques to calculate the surface energy, including the method of "ab initio atomistic thermodynamics". The Cu2O(111) surface with (1 × 1) periodicity and surface copper vacancies is identified as the most stable at all oxygen partial pressures, although the ideal stoichiometric Cu2O(111) surface is relatively close in energy under oxygen-poor conditions. These surfaces are then used to calculate the band edges. Comparison of the band edges to redox potentials reveals that Cu2O is thermodynamically capable of photocatalytic reduction of CO2 to methanol and the reduction and oxidation of water.
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