Weakened Interfacial Hydrogen Bond Connectivity Drives Selective Photocatalytic Water Oxidation toward H2O2 at Water/Brookite-TiO2 Interface

作者：Guanhua Ren, Min Zhou, Haifeng Wang · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.3c13402 · 被引用次数：94 · 研究领域：Advanced Photocatalysis Techniques、TiO2 Photocatalysis and Solar Cells、Electrochemical Analysis and Applications

The formation of H 2 O 2 through the two-electron photocatalytic water oxidation reaction (WOR) is significant but encounters the competition with the four-electron O 2 evolution reaction. Recent studies showed a crystal-phase dependence in H 2 O 2 selectivity, where high purity brookite TiO 2 (b-TiO 2 ) exhibits remarkable H 2 O 2 selectivity in contrast to the common rutile phase TiO 2 (r-TiO 2 ). However, the origin of such a structure-induced selectivity preference remains elusive, primarily due to the complexities associated with the solid–liquid interface system and excited-state chemistry. Herein, we conducted a comprehensive investigation into the selectivity mechanism of WOR at the water/b-TiO 2 (210) and water/r-TiO 2 (110) interfaces, employing first-principles molecular dynamics simulations and microkinetic analyses. Intriguingly, our results reveal that the intrinsic catalytic ability of the b-TiO 2 (210) itself does not enhance H 2 O 2 selectivity compared to r-TiO 2 (110). Instead, it is the weakened interfacial hydrogen bond connectivity, modulated by the herringbone-like local atomic structure of the b-TiO 2 (210) surface, that determines the selectivity. Specifically, this weakened H-bond connectivity (i.e., local low water density) at the interface, owing to the strong water adsorption and distinct adsorption orientation, can stabilize the OH • radical and inhibit its deprotonation, leading to an improved H 2 O 2 selectivity. By contrast, the relatively str...