Spontaneous Exciton Dissociation in Sc-Doped Rutile TiO2 for Photocatalytic Overall Water Splitting with an Apparent
Fei Qin1,2, Yuyang Kang1,2, Xingyuan San3
1Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
Abstract:
Achieving high-efficiency photocatalytic overall water splitting with earth-abundant materials like TiO2 under ambient conditions is a compelling renewable energy solution. However, this remains challenging due to both the presence of rich deep-level defects and lack of strong driving force in particulate photocatalysts, limiting the separation of photogenerated charges. Here, we developed a scandium (Sc)-doped rutile TiO2 with fully passivated detrimental Ti3+ defects and very strong built-in electric field arising from engineered (101)/(110) facet junctions. The Sc3+ doping enables a much lower exciton binding energy of 8.2 meV (28.6 meV for undoping) than room-temperature thermal fluctuation energy, indicating spontaneous exciton dissociation. These features enable the photogenerated electrons and holes to selectively transfer to the (110) and (101) facets, respectively. The resulting Sc-doped TiO2 with cocatalyst delivers photocatalytic overall water splitting with an apparent quantum yield of 30.3% at 360 nm and a solar-to-hydrogen conversion efficiency of 0.34%, representing the highest values reported for TiO2-based photocatalysts under ambient conditions.
More Related Videos
Related Concept Videos
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
01:26Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
01:25Deactivation Processes: Jablonski Diagram
01:17Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...