Charge generation and separation are two key processes for semiconductor photocatalysis. Here, we use Pt as a single atom catalyst to systematically examine the facet-dependent electronic band structure and light absorption of the layered perovskite-type wide-gap semiconductor, lanthanum titanium oxide (La₂Ti₂O₇, LTO) by means of density functional theory simulations. It is found that single Pt atom doping of different LTO surfaces (here, (100), (101) and (001)) can not only create states in the bandgap that would promote the formation of recombination centers, but also shift the optical absorption edge to the visible region. Interestingly, the Pt doping forms a heterojunction, with the valence band maximum consisting of Pt states and the conduction band minimum consisting of LTO states, respectively. To study the facet dependent surface activity, acetic acid (CH₃COOH) was used as a model molecule to investigate the adsorption and charge transfer on the (101), (100) and (001) Pt-LTO surface facets. The results show that that the (101) facet could enable stronger adsorption of CH₃COOH by promoting more electron transfer during the interfacial interaction. Our theoretical findings aim to promote the design and optimization of the single atom catalysts (SACs) for photocatalytic applications and other broad catalysis systems.

电荷产生和分离是半导体光催化的两个关键过程。在这里，我们使用 Pt 作为单原子催化剂来系统地检查层状钙钛矿型宽隙半导体镧钛氧化物 (La ₂ Ti ₂ O ₇, LTO) 通过密度泛函理论模拟。发现不同 LTO 表面（此处为（100）、（101）和（001））的单个 Pt 原子掺杂不仅可以在带隙中产生促进复合中心形成的状态，还可以改变光吸收边缘到可见区域。有趣的是，Pt 掺杂形成异质结，价带最大值分别由 Pt 态组成，导带最小值分别由 LTO 态组成。为了研究面相关的表面活性，使用乙酸 (CH ₃ COOH) 作为模型分子来研究 (101)、(100) 和 (001) Pt-LTO 表面上的吸附和电荷转移。结果表明，(101)面可以使CH _{3 的}吸附能力更强COOH 通过在界面相互作用过程中促进更多的电子转移。我们的理论发现旨在促进用于光催化应用和其他广泛催化系统的单原子催化剂 (SAC) 的设计和优化。