Interfacial co-existence of oxygen and titanium vacancies in nanostructured TiO₂ for enhancement of carrier transport

Abstract

The interfacial co-existence of O- and Ti-vacancies in crystalline TiO2 assisted by rGO sheets is fabricated, improving carrier transport with a unique electron pathway from O- to Ti-vacancies, and minimizing energy loss with a nano-fusion interface between TiO2 and rGO.

Photoinduced Terminal Fluorine and Ti 3+ in TiOF 2 /TiO 2 Heterostructure for Enhanced Charge Transfer

“…[31][32][33] Additionally, a small peak was observed at g = 2.001 after light irradiation, which could be attributed to oxygen vacancies. 25,28 Together with the 19 F NMR results, we inferred that the terminal Ti 1 -F sites and Ti 3+ defects were induced under the UV-vis light irradiation, and the content increased with irradiation time. X-ray photoelectron spectroscopy (XPS) investigations of TiOF 2 /TiO 2 , TiOF 2 , and TiO 2 before and after irradiation yielded information about the chemical state of the surface.…”

“…24 Note that this very thick nanofusion domain could interconnect with the ordered lattice fringes of TiOF 2 and TiO 2 , which also enabled the quantized ballistic transport of electrons, and thus, beneficial for the enhancement of charge mobility and the minimization of energy loss. [25][26][27][28] To clarify the structure of the F-doped interface in TiOF 2 /TiO 2 , 19 F solid-state NMR spectroscopy was performed. As shown in Figure 2a, the NMR signal at ∼15 ppm with multiple spin sidebands assigned to the Ti 2 -F from the TiOF 2 lattice was identified in both TiOF 2 and TiOF 2 / TiO 2 .…”

Insight into the Real Efficacy of Graphene for Enhancing Photocatalytic Efficiency: A Case Study on CVD Graphene-TiO2 Composites

“…34 The O 1s XPS patterns (Figure 5b) display two peaks at 529.9 and 531.3 eV, which are ascribed to lattice O (Ti−O) and hydroxyl O (−OH), respectively. 35,36 The binding energies of Ti 2p and O 1s for CVDG-TiO 2 are similar to that of the RGO-TiO 2 composite, suggesting the same electronic interactions between TiO 2 and graphene (CVDG and RGO). In addition, it is notable that no typical peak between the binding energy of 454.9 and 460.9 eV is observed, which is generally assigned to the metal−carbon (T−C) bond.…”

Role of Vacancies in Photocatalysis: A Review of Recent Progress

“…Then, they recently developed a new co-existence titanium and oxygen vacancies at the interface between TiO 2 and rGO via the two-step calcination. [70] The formation mechanism is shown in Figure 13e, the C atoms of rGO could extract interfacial lattice O atom of rGO forming O-vacancies under calcination at 500°C in Ar atmosphere, then O-rich domains with distortions and concomitant Ti-vacancies appear after the calcination treatment at 350°C in air. As expected, the interfacial carrier transport from O-vacancies to Ti-vacancies and rGO sheets was facilitated as measured by EIS and transient photocurrent response, promoting the photocatalytic H 2 production and CO 2 reduction activity.…”

“…This work shines light on the novel charge separation strategy through precise defect design in homogenous materials. Then, they recently developed a new co‐existence titanium and oxygen vacancies at the interface between TiO 2 and rGO via the two‐step calcination [70] . The formation mechanism is shown in Figure 13e, the C atoms of rGO could extract interfacial lattice O atom of rGO forming O‐vacancies under calcination at 500 °C in Ar atmosphere, then O‐ rich domains with distortions and concomitant Ti‐vacancies appear after the calcination treatment at 350 °C in air.…”