Brlec Katarina, Savory Christopher N, Scanlon David O
Department of Chemistry and Thomas Young Centre, University College London London UK
J Mater Chem A Mater. 2023 Jul 20;11(31):16776-16787. doi: 10.1039/d3ta02801a. eCollection 2023 Aug 8.
Utilising photocatalytic water splitting to produce green hydrogen is the key to reducing the carbon footprint of this crucial chemical feedstock. In this study, density functional theory (DFT) is employed to gain insights into the photocatalytic performance of an up-and-coming photocatalyst YTiOS from first principles. Eleven non-polar clean surfaces are evaluated at the generalised gradient approximation level to obtain a plate-like Wulff shape that agrees well with the experimental data. The (001), (101) and (211) surfaces are considered further at hybrid-DFT level to determine their band alignments with respect to vacuum. The large band offset between the basal (001) and side (101) and (211) surfaces confirms experimentally observed spatial separation of hydrogen and oxygen evolution facets. Furthermore, relevant optoelectronic bulk properties were established using a combination of hybrid-DFT and many-body perturbation theory. The optical absorption of YTiOS weakly onsets due to dipole-forbidden transitions, and hybrid Wannier-Mott/Frenkel excitonic behaviour is predicted to occur due to the two-dimensional electronic structure, with an exciton binding energy of 0.4 eV.
利用光催化水分解来生产绿色氢气是降低这种关键化学原料碳足迹的关键。在本研究中，采用密度泛函理论（DFT）从第一性原理深入了解一种新兴光催化剂YTiOS的光催化性能。在广义梯度近似水平下评估了11个非极性清洁表面，以获得与实验数据吻合良好的板状Wulff形状。在杂化DFT水平上进一步考虑（001）、（101）和（211）表面，以确定它们相对于真空的能带排列。基面（001）与侧面（101）和（211）表面之间的大能带偏移证实了实验观察到的析氢和析氧面的空间分离。此外，结合杂化DFT和多体微扰理论确定了相关的光电体性质。YTiOS的光吸收由于偶极禁戒跃迁而微弱起始，并且由于二维电子结构预计会出现杂化Wannier-Mott/弗伦克尔激子行为，激子结合能为0.4 eV。
