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The effect of group IIIA metal ion dopants on the photocatalytic activities of nanocrystalline Sr0.25H1.5Ta2O6·H2O†
* Corresponding authors
a State Key Laboratory Breeding Base of Photocatalysis, Research Institute of Photocatalysis, Fuzhou University, Fuzhou, trung quốc E-mail: wuling
Xem thêm: Tra Từ: Tình Thú Nghĩa Là Gì ??? Nghĩa Của Từ Tình Thư Trong Tiếng Việt
b State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, đài loan trung quốc
A series of group IIIA metal ion electron acceptors doped into Sr0.25H1.5Ta2O6·H2O (HST) samples have been prepared by an impregnation và calcination method for the first time. The samples are characterized by XRD, TEM, DRS và XPS. The variations in the electronic structure & photoelectric response after metal ion doping are investigated by theoretical calculations & photocurrent experiments, respectively. Results show that the metal ions can be efficiently incorporated into the HST crystal structure, which is reflected in the lattice contraction. Meanwhile, the photoabsorption edges of the metal-doped HST samples are red shifted to a longer wavelength. Taking into tài khoản the ionic radii và electronegativities of the dopants, as well as the XRD và XPS results, it is concluded that Ta5+ ions may be partially substituted by the Al3+ and Ga3+ ions in the framework, while In3+ ions are the favourable substitutes for Sr2+ sites in the cavity. The first-principles DFT calculations confirm that the variation of the band structure is sensitive lớn the type of group IIIA metal ion. Introducing the dopant only at the Ta site induces an obvious variation in the band structure & the band gap becomes narrow. Meanwhile, an ‘‘extra step’’ appeared in the band gap, which can trap photogenerated electrons from the valance band (VB) và could enhance the charge mobility & the photocurrent. For the photocatalytic degradation of methyl orange in an aqueous solution & in benzene in the gas phase, the doped samples show superior photocatalytic activities compared with both undoped samples và TiO2. The enhanced photocatalytic activities can be well explained by their electronic structure, photoabsorption performance, photoelectric response, and the concentration of the active species. Due khổng lồ the fact that Ga ion doping can create an acceptor impurity level and change the electronic band, efficiently narrowing the band gap, the Ga-doped sample shows the highest photocatalytic activity.