Flame Synthesized Blue TiO_2−x with Tunable Oxygen Vacancies from Surface to Grain Boundary to Bulk

Abstract

Fabrication of nonstoichiometric metal oxides containing oxygen vacancies (OVs) has been an effective strategy to modulate their (photo)catalytic or (photo)electrochemical performances which are all affected by charge transfer at the interface and in the bulk. Considerable efforts are still needed to achieve tunability of OVs, as well as their quantitative characterization. Herein, a one‐step flame synthesis method is reported for the first time for fast fabrication of blue TiO2−x with controllable defect content and location. Temperature‐programmed oxidation (TPO) analysis is applied for the first time and found to be an excellent technique in both differentiating and quantifying OVs at the surface, grain boundary (GB), and bulk of TiO2−x. The results indicate that a moderate level of OVs can greatly enhance the charge transfer. Importantly, the OVs locked at GBs due to the thermal sintering of nanoparticles during the synthesis can facilitate the anchoring and reduction of Pt species.

Super-resolution imaging of photogenerated charges on CdS/g-C3N4 heterojunctions and its correlation with photoactivity

“…S9b † XPS analysis was conducted to analyze the chemical valence of Pt and Pb after the photoreactions. Since metallic Pt 0 is regarded as the active site for photocatalytic H 2 generation, 45 its percentage in the Pt species will largely affect the photocatalytic activity. As shown in Fig.…”

Flame Synthesis of Carbon and Metal-Oxide Nanoparticles: Flame Types, Effects of Combustion Parameters on Properties and Measurement Methods

“…Furthermore, at values of φ larger than one, the intermediate species in the formation pathway of NPs are identified as oxygen deficient. Consequently, the particles at the end of the synthesis have a high concentration of oxygen vacancies (OVs), resulting in amorphous structures [ 55 ].…”

Defect engineering of electrode materials towards superior reaction kinetics for high-performance supercapacitors

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