Monolayer H_1.07Ti_1.73O₄·H₂O nanosheets with the thickness about 0.67 nm were prepared and developed as an efficient photocatalyst for hydrogen evolution. The prepared sample exhibits greatly improved photocatalytic activity with more 10.5 times higher than its layered counterpart. The morphologies, microstructures, superficial properties and electronic structures of the sample were characterized by XRD, TEM, AFM, BET, and UV–vis DRS in detail. Moreover, EXAFS, FTIR, XPS and in-suit FTIR of D₂O absorption results suggested that Ti vacancies result in the formation of abundant active O species around vacancies sites, which can be exposed fully in the monolayer nanosheets and bind with water molecules in the formation of surface coordination via hydrogen bonds. An efficient electron transition from nanosheets to surficial coordinated H₂O molecules takes place. Finally, a synergistic effect between titanium vacancies and ultrathin 2D structure was proposed to elucidate that the enhanced photocatalytic performance over metal defects may be attributed to efficient exposure of active species and transition of photo-electrons from surface to H₂O molecules.

中文翻译：

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单层H _1.07 Ti _1.73 O ₄ ·H ₂ O纳米片上的光催化氢逸出：金属缺陷的作用和性能大大提高

制备了厚度约为0.67 nm的单层H _1.07 Ti _1.73 O ₄ ·H ₂ O纳米片，并将其开发为一种高效的氢析出光催化剂。所制备的样品显示出大大改善的光催化活性，比其层状对应物高10.5倍。通过XRD，TEM，AFM，BET和UV-vis DRS对样品的形貌，微观结构，表面性质和电子结构进行了详细表征。此外，D _2的EXAFS，FTIR，XPS和内置FTIRO的吸收结果表明，Ti空位导致空位附近形成了丰富的活性O，可以在单层纳米片中充分暴露并与水分子结合，通过氢键形成表面配位。发生了从纳米片到表面配位的H ₂ O分子的有效电子跃迁。最后，提出了钛空位和超薄2D结构之间的协同效应，以阐明对金属缺陷的增强光催化性能可能归因于有效物种的有效暴露以及光电子从表面到H ₂ O分子的转变。