煅烧温度对{0 0 1}面暴露的锐钛矿型TiO 2纳米片的形貌和光催化活性的影响,Applied Catalysis B: Environment and Energy
探索具有优异的热稳定性和光催化活性的锐钛矿型TiO 2极为重要且具有挑战性。在本工作中，通过在200℃的氢氟酸溶液中对钛酸四丁酯进行水热处理24 h，制得了具有显着高反应性{0 0 1}面的主要表面氟化锐钛矿TiO 2纳米片。所制备的锐钛矿型TiO 2纳米片表现出显着的热稳定性，可抵抗高达1100°C的相变，这与表面氟化有关。煅烧处理加速了表面结合的氟从{0 0 1}面的解吸，这首先导致形成氧空位，然后导致相邻的TiO 2熔融沿[0 0 1]方向（c轴）排列的纳米片，以最小化表面能。高结晶度（低杂质）和氧空位是所制备的TiO 2纳米片材的高热稳定性的原因。另一方面，热处理由于质地，结晶度和表面化学状态的变化而影响光催化活性。出人意料的是，在高达1100°C的高温下，仍可保持较高的光催化活性，以便在紫外线照射下对空气中的丙酮进行光催化氧化分解。
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Effect of calcination temperature on morphology and photocatalytic activity of anatase TiO2 nanosheets with exposed {0 0 1} facets
Exploring anatase TiO2 with superior thermal stability and photocatalytic activity is of great importance and challenging. In the present work, surface-fluorinated anatase TiO2 nanosheets with dominant high reactive {0 0 1} facets were fabricated by hydrothermal treatment of tetrabutyl titanate in hydrofluoric acid solution at 200 °C for 24 h. The as-prepared anatase TiO2 nanosheets show a remarkable thermal stability against phase transition up to 1100 °C, which is associated with the surface fluorination. Calcination treatment accelerates the desorption of surface-bounded fluorine from the {0 0 1} facets, which results in the formation of oxygen vacancy first, and then the fusion of neighbor TiO2 nanosheets along the [0 0 1] direction (c-axis) to minimize the surface energy. High crystallization (low impurity) and oxygen vacancy are responsible for the high thermal stability of the as-prepared TiO2 nanosheets. On the other hand, heat treatment influences the photocatalytic activity as a result of the change of the textural characteristics, crystallinity degree and surface chemical states. Surprisingly, high photocatalytic activity is still remained up to 1100 °C for photocatalytic oxidation decomposition of acetone in air under UV light illumination.