氧化剂
铁电性
极化(电化学)
催化作用
电场
化学物理
光催化
极化密度
密度泛函理论
材料科学
外延
化学
凝聚态物理
纳米技术
物理化学
计算化学
光电子学
电介质
磁场
有机化学
物理
图层(电子)
量子力学
磁化
作者
Nathalie Vonrüti,Ulrich Aschauer
摘要
Surface properties of ferroelectrics are promising for catalysis due to the spontaneous electric polarization that can be reversed by an applied electric field. While several theoretical studies show different catalytic activities for differently polarized ferroelectric surfaces at zero electric potential, little work was devoted to catalysis on ferroelectric surfaces at higher electric potentials. Under these conditions that are relevant for photocatalytic experiments and applications, surfaces are usually oxidized. Using density functional theory calculations, we show for LaTiO2N and BaTiO3 that this oxidation heavily impacts and even determines the electronic properties of the catalyst surface and therefore leads to similar reaction free energies for the catalytic steps of the oxygen evolution reaction, irrespective of the bulk polarization. This is opposed to experimental studies, which found different activities for differently polarized catalyst surface domains under oxidizing conditions. We therefore conclude that the experimentally observed activity difference does not originate from the surface polarization following the bulk polarization, but rather from different bulk polarization directions leading to different adsorbate coverages or even surface reconstructions.
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