Direct Observation of Oxygen Vacancy Self‐Healing on TiO₂ Photocatalysts for Solar Water Splitting

Abstract

Oxygen vacancy (Vo) on transition metal oxides playsacrucial role in determining their chemical/physical properties.C onversely,t he capability to directly detect the changing process of oxygen vacancies (Vos) will be important to realize their full potentials in the related fields.Herein, with an ovel synchronous illumination X-rayp hotoelectron spectroscopy( SI-XPS) technique,w ef ound that the surface Vos (surf-Vos) exhibit astrong selectivity for binding with the water molecules,and sequentially capture an oxygen atom to achieve the anisotropic self-healing of surface lattice oxygen. After this self-healing process,t he survived subsurface Vos( sub-Vos) promote the charge excitation from Ti to Oa toms due to the enriched electron located on low-coordinated Ti sites.H owever,t he excessive sub-Vos would blockt he charge separation and transfer to TiO 2 surfaces resulted from the destroyed atomic structures.T hese findings open an ew pathwayt o explore the dynamic changes of Vosand their roles on catalytic properties,not only in metal oxides,but in crystalline materials more generally.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Water–Gas Shift Reaction on Titania-Supported Single-Metal-Atom Catalysts: The Role of Cation (Ti) and Oxygen Vacancy

“…The overall water spitting process of surface oxygen vacancy on TiO 2 includes water adsorption, dissociation, and hydrogen desorption. First, water is dissolved on the oxygen vacancy and then one of the H will preferentially adsorb on the adjacent unsaturated oxygen atom, thereby forming hydroxyls . The Δ G of step (4) for six transition metals are similar, which indicates that the influence of adjacent single atoms in this step is negligible.…”

Light-driven oxygen evolution from water oxidation: TiO2 engineering in the performance of the immobilised photocatalysts

“…Among the defects identi ed in TiO 2 , the presence of oxygen vacancies (O v ) can act as active adsorption sites, and strongly in uence the reactivity of the photocatalysts 22 . Additionally, the formation of O v commonly leads to the creation of unpaired electrons that can generate donor levels in the electronic structure of the TiO 2 24,25 . As observed in Fig.…”

Cu-doping SnO2-NiO p-n Heterostructure for Significant Raman Enhancement with EF > 1010: Toward Ultrasensitive VOCs Sensing

“…2j) 22 . From O 1s XPS spectrum of SnO2-NiOx/Cu, three peaks were clearly observed, in which O1s peak at 532.2 eV was ascribed to the lattice oxygen (O 2-), while the high binding energy (533.3 eV) was assigned to the absorbed oxygen ions (O 2and O -) on the surface 23 , which were consistent with those of SnO2-NiO. In addition, another peak at the lower energy (531.0 eV) was attibuted to the vacant oxygen (OV) 24 , indicating that Cu doping induced a large number of OV in SnO2-NiOx/Cu.…”