A facile hydrothermal etching process to in situ synthesize highly efficient TiO₂/Ag nanocube photocatalysts with high-energy facets exposed for enhanced photocatalytic performance

Abstract

A facile hydrothermal etching process was developed to synthesize TiO 2 /Ag nanocubes for enhanced photocatalytic application. The synthesis was carried out by chemically etching hollow @TiO 2 spheres in the presence of an AgF or AgF/NaF solution under hydrothermal conditions. Utilizing F − as a morphologydirecting agent and Ag + as an Ag source during the etching process, TiO 2 nanocubes can be easily formed with their active high-energy facets exposed and Ag nanoparticles can be in situ deposited simultaneously on the surface of the TiO 2 nanocubes to generate hybrid TiO 2 /Ag nanocubes. The resulting TiO 2 /Ag nanocubes were well controlled with Ag nanoparticles uniformly distributed on the surface of the TiO 2 nanocubes. The morphologies of TiO 2 /Ag can be altered from ellipsoidal to cubic shapes depending on the amounts of AgF or AgF/NaF used for chemical etching. Due to the exposure of the active high-energy facets of TiO 2 and the uniform deposition of Ag nanoparticles, the obtained TiO 2 /Ag nanocubes showed superior catalytic performance for the photocatalytic degradation of rhodamine B under visible-light radiation. It is proposed that the surface plasmon resonance effect arisen from Ag nanoparticles on TiO 2 nanocubes can effectively enhance the visible-light driven photocatalytic properties of TiO 2 /Ag photocatalysts. Meanwhile, due to the etching of F ions during the synthetic process, the morphology variation of TiO 2 from spherical to cubic shapes may be beneficial to the exposure of high energy {001} facets, which is liable to produce more electron-hole pairs in the photocatalytic process, and electron-hole pairs can combine with OH − to produce large amounts of hydroxyl radicals, eventually accelerating the decomposition of the organic dye.

Synthesis of Al-MCM-41@Ag/TiO2 Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene

“…e spectrum confirmed the presence of O, Si, Al, Ti, and Ag elements without any other impurities. Figure 7(b) is the high-resolution XPS spectrum e splitting energy between Ag 3d 5/2 and Ag 3d 3/2 is 6 eV, which further confirmed the existence of metallic Ag nanoparticles in the synthesized Al-MCM-41@0 1Ag/TiO 2 material [35,38]. It is also clearly observed that the presence of two different peaks for Ag 3d 5/2 binding energies at 368.1 eV and 367.6 eV were assigned to metallic silver (Ag 0 ) and silver ions in Ag 2 O (Ag + ), respectively [39].…”

Preparation of transparent nanostructured N-doped TiO2 thin films by combination of sonochemical and CVD methods with visible light photocatalytic activity

“…Moreover, in comparison with the thin films deposited on quartz substrate, the films on glass substrate have higher photocatalytic performance, because of the special nanocube morphology of the thin films deposited on glass substrate. As reported in previous works, because of the sharp corners and edges of photocatalysts with nanocube morphology and increased exposure of high-energy (001) facets in such structure, the photocatalysts with such morphology have higher photocatalytic activity [22][23][24][25][26]57].…”

“…In a similar work by Zhao et al [23], the anatase nanocuboid TiO 2 showed high photocatalytic activity owing to the increased exposure of active (100) and (001) facets. There are some other similar reports in the literature about the high photocatalytic performance of TiO 2 and N-doped TiO 2 nanocubes because of the increased exposure of active (100) and (001) facets on their surface [24][25][26].…”

Synthesis and photocatalytic properties of three dimensional laminated structure anatase TiO2/nano-Fe0 with exposed (001) facets

“…21,36,37 In the study of TiO 2 assisted modication, the addition of transition and/or noble metals is one of the promising methods to improve the photocatalytic activity and photoelectric effect of TiO 2 . [38][39][40][41] Due to the formation of doping energy and the rapid transfer of the photogenerated electrons from the semiconductors to the dopants, the doped metal such as Fe, Pt, Mo, Cr, Ag and Au can reduce the recombination rate of electrons and holes. 42 As a new environmental remediation engineering material, nano-zerovalent iron (nano-Fe 0 ) has been widely used in the eld of environmental remediation.…”