A reverse slipping strategy for bulk-reduced TiO2−x preparation from Magnéli phase Ti4O7†,Inorganic Chemistry Frontiers

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A reverse slipping strategy for bulk-reduced TiO2−x preparation from Magnéli phase Ti4O7†
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2019-10-22 , DOI: 10.1039/c9qi01042d
Jiantao Huang _{1,

2,

3,

4,

5} , Xiangli Che _{1,

2,

3,

4,

5} , Jijian Xu _{1,

2,

3,

4,

5} , Wei Zhao _{1,

2,

3,

4,

5} , Fangfang Xu _{1,

2,

3,

4,

5} , Fuqiang Huang _{1,

2,

3,

4,

5}

Affiliation

Black TiO_2−x is an attractive material due to its adjustable band structure, useful in different applications, and has been heavily investigated and developed. The current reduction of TiO₂ involves a process from surface to center: thus, the issue of either insufficient or excessive reduction seems inevitable. To the best of our knowledge, it is rarely reported that a homogeneous defect distribution can be facilely achieved inside black TiO_2−x. In this study, a bulk-reduced rutile TiO_2−x was obtained via a circuitous two-step approach, with an intermediate Magnéli phase (Ti_nO_2n−1). With the decomposition of a solid atmosphere creator (e.g. KClO₄ grains) at a high temperature, the missing oxygen ions in Ti₄O₇ could be replenished quantitatively. The TEM and SAED results reveal that the oxidation process is not just a surface reaction, but it involves reverse displacement or structural rearrangement inside the crystal. In particular, the periodic variation of crystallographic sheer planes was the direct evidence of the above bulk reaction, i.e. unified long period for Ti₄O₇ and varied long period for critical ratio sample. The as-prepared samples showed different band gaps and colors, based on their oxygen content. KClO₄, with a critical mixing ratio of around 17.5 mol%, could almost oxidize Ti₄O₇ to black rutile TiO_2−x. Furthermore, the sample formed at the critical ratio showed a considerable photo-thermal response speed of 1.7 °C s⁻¹ and an equilibrium temperature of up to 70 °C under irradiation with light above 400 nm, which can be an evidence for the enhancement of non-intrinsic absorption. In short, this study provides a new route for the controllable preparation of black TiO_2−x, and a possibility for further development of other solid atmosphere creators.

中文翻译：

从Magnéli相Ti ₄ O ₇† 大量还原TiO _{2− x}制备的反向滑移策略

黑色TiO _{2- x}由于其可调节的能带结构而成为一种有吸引力的材料，可用于不同的应用，并且已经得到了广泛的研究和开发。当前的TiO ₂还原涉及从表面到中心的过程：因此，还原不足或过量的问题似乎是不可避免的。据我们所知，很少有报道可以在黑色TiO _{2- x}内部容易地实现均匀的缺陷分布。在这项研究中，通过a回两步法获得了块状还原的金红石型TiO ₂ - _x，中间为马格尼利相（Ti _n O ₂_n_-1）。通过在高温下分解固体气氛产生剂（例如KClO ₄晶粒），可以定量地补充Ti ₄ O _7中缺失的氧离子。TEM和SAED结果表明，氧化过程不仅是表面反应，而且还涉及晶体内部的反向位移或结构重排。特别地，晶体学剪切平面的周期性变化是上述本体反应的直接证据，即Ti ₄ O _7的统一长周期和临界比样品的长周期变化。所制备的样品根据其氧含量显示出不同的带隙和颜色。氯化钾₄临界混合比约为17.5 mol％时，几乎可以将Ti ₄ O ₇氧化成黑色金红石型TiO _{2- x}。此外，在高于400 nm的光照射下，以临界比形成的样品在1.7°C s ^-1的光热响应速度和高达70°C的平衡温度下显示出可观的光热响应速度，这可能是增强的证据。非本征吸收。简而言之，这项研究为可控制的黑色TiO _{2- x的}制备提供了一条新途径，并为进一步开发其他固体气氛产生剂提供了可能性。

更新日期：2019-12-18

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