In this work, we have shown that aluminium acetylacetonate (Al(acac)₃) can be used as the catalyst to synthesize Ti³⁺ self-doped TiO₂ (Ti³⁺-TiO₂) by sol–gel method in air. Ti³⁺-TiO₂ can be obtained directly and Al(acac)₃ is removed during the annealing process. Ti³⁺ concentrates in the surface layer of powders, making a homojunction between Ti³⁺-TiO₂ in the surface layer and TiO₂ in the bulk. Based on the scheme of Zielger-Natta catalysts and the characterization of the sols and gels of samples, the synthesis mechanism of Ti³⁺ is proposed as the combination of steric hindrance effect, Lewis acid-base reaction and crystal field effect and Al(acac)₃ acts as the catalyst in the reaction. Charge generation, charge transport and interface reactions, all of the three crucial strategies of photocatalytic are improved through the self-doped Ti³⁺, resulting in enhanced photocatalytic and photoelectrochemical activities. Compared with the reported methods, this work proposes a simple and novel route for the preparation of Ti³⁺-TiO₂, which would facilitate the preparation and application of TiO₂ photocatalyst.

在这项工作中，我们证明了乙酰丙酮铝（Al（acac）₃）可以用作在空气中通过溶胶-凝胶法合成Ti ³⁺自掺杂TiO ₂（Ti ³⁺ -TiO ₂）的催化剂。可以直接获得Ti ³⁺ -TiO _2，并在退火过程中去除Al（acac）₃。Ti ³⁺集中在粉末的表面层中，使表面层中的Ti ³⁺ -TiO ₂与块状体中的TiO ₂之间形成同质结。根据Zielger-Natta催化剂的方案和样品的溶胶和凝胶的表征，Ti的合成机理提出了³⁺作为空间位阻效应，路易斯酸碱反应和晶场效应的结合体，并且Al（acac）₃充当了该反应的催化剂。通过自掺杂Ti ³⁺可以改善电荷产生，电荷传输和界面反应，这三个关键的光催化策略都得到了改善，从而增强了光催化和光电化学活性。与已报道的方法相比，这项工作提出了一种简单而新颖的制备Ti ³⁺ -TiO _2的途径，这将有助于TiO ₂光催化剂的制备和应用。