Light absorption and photocatalysis of flake-like titanate nanosheets chemically modified by organic ligands
Light absorption and photocatalysis of flake-like titanate nanosheets chemically modified by organic ligands
复制标题
有机配体化学修饰片状钛酸酯纳米片的光吸收与光催化
DOI：
10.2109/jcersj2.20051
复制
发表时间：
2020
影响因子：
1.1
通讯作者：
Y. Ohya
中科院分区：
文献类型：
--
作者：
T. Ban;Hiroki Yamada;Kota Imaeda;Tomohiro Inoue;C. Takai;Y. Ohya
考察了有机配体化学修饰的钛酸盐纳米fi在光催化剂中的应用。由于量子尺寸eff等原因，钛酸盐纳米片具有很宽的带隙。钛酸盐纳米片光催化需要波长很短的紫外光。为了解决这一问题，我们用有机配体对钛酸酯纳米片进行了fi改性，并利用有机配体向钛酸酯纳米片的电荷转移进行光催化。采用自下而上的方法在水溶液中合成了钛酸盐纳米片。以邻苯二酚、过氧化氢和2，5-二羟基对苯二甲酸为有机配体。在钛酸盐纳米片状溶胶中加入有机配体后，配体优先吸附在纳米片状溶胶的边缘。配体的吸附使其能够吸收长波长的光。在邻苯二酚和双氧水存在的情况下，通过光照射，发生了从配体的最高占据分子轨道(HOMO)能级到纳米片导带的电荷转移。另一方面，吸附的DHTP引起了光敏化，即从HOMO通过配体的最低空位分子轨道转移到纳米片的导带。此外，通过将[Ag(NH3)2]+还原为金属银纳米颗粒，研究了H2 O2或fi修饰的钛酸盐纳米片的光催化性能。用H2 O2修饰的钛酸盐纳米片fi没有光催化反应，而用DHTP修饰的钛酸酯纳米片通过光催化形成了银纳米颗粒。这种差异可能与光致发光形成的电子和空穴复合的速度有关，这可能与光致电荷转移的机制有关。
The application of titanate nanosheets chemically modi fi ed by organic ligands to a photocatalyst was examined. Titanate nanosheets have very wide band gap, because of quantum size e ff ect. Ultraviolet light with very short wavelength is required for photocatalysis of titanate nanosheets. In order to circumvent this problem, titanate nanosheets were modi fi ed by organic ligands, and the charge transfer from the organic ligands to titanate nanosheets was utilized for photocatalysis. Titanate nanosheets were synthesized by bottom-up process in aqueous solution. Catechol, hydrogen peroxide (H 2 O 2 ), and 2,5-dihydroxyterephthalic acid (DHTP) were used as an organic ligand. Upon adding organic ligands to titanate nanosheet sols, the ligands were adsorbed preferentially on the edge of nanosheets. The adsorption of ligands enabled the absorption of light with a long wavelength. In the case using catechol and H 2 O 2 , the charge transfer from the Highest Occupied Molecular Orbital (HOMO) level of ligands to the conduction band of nanosheets occurred by photo-irradiation. On the other hand, the adsorbed DHTP caused photo-sensitization, that is, the charge transfer from HOMO through Lowest Unoccupied Molecular Orbital of ligands to the conduction band of nanosheets. Furthermore, the photocatalysis of the titanate nanosheets modi fi ed by H 2 O 2 or DHTP was investigated by utilizing the reduction of [Ag(NH 3 ) 2 ] + to metallic Ag nanoparticles. The titanate nanosheets modi fi ed by H 2 O 2 did not exhibit photocatalytic reactions, while in the case using DHTP, the formation of Ag nanoparticles by photocatalysis was observed. Probably, this di ff erence was attributed to the rate of the recombination of electrons and holes formed by photo-irradiation, which was likely dependent on the mechanism of the charge transfer caused by photo-irradiation.