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 TiO_2−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 TiO_2−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.

中文翻译：

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火焰合成的蓝色 TiO2−x 具有从表面到晶界再到块体的可调氧空位

制备含有氧空位 (OV) 的非化学计量金属氧化物已成为调节其（光）催化或（光）电化学性能的有效策略，这些性能均受界面和体中电荷转移的影响。仍然需要付出相当大的努力来实现 OV 的可调性，以及它们的定量表征。在此，首次报道了一种一步式火焰合成方法，用于快速制备具有可控缺陷含量和位置的蓝色 TiO _{2- x}。首次应用程序升温氧化 (TPO) 分析，发现它是区分和量化表面、晶界 (GB) 和 TiO _{2- x}体积的 OV 的出色技术. 结果表明，中等水平的 OV 可以大大增强电荷转移。重要的是，由于合成过程中纳米粒子的热烧结，OV 锁定在 GB 上，可以促进 Pt 物种的锚定和还原。