Silvered TiO₂ for Facet-Dependent Photocatalytic Denitrification

Abstract

In this paper, the influence of exposed facets of silvered TiO2 photocatalysts for photodenitrification was fundamentally investigated. We found that photodeposition of silver on 001-faceted TiO2 was prone to form Ag/Ag2O/001-TiO2 triple junctions. Comparatively, oxygen vacancies in 101-faceted TiO2 alleviated the oxidation rate, which contributed to the formation of a junctioned interface between TiO2 and metallic Ag0. Benefiting from the Z-scheme charge transfer pathway mediated by adjacent Ag, the nitrate reduction rate and N2 selectivity for Ag2O/Ag/101-TiO2 reached 99.1 and 81.1%, respectively, which were much higher than those of silvered 001-TiO2 and P25. In this work, we prepared TiO2-based photocatalysts with specific exposed crystal facets and good crystallinity at the heterogeneous interface for denitrification applications.

Photocorrosion Inactivation of Ag2O/TiO2 Photocatalysts and the Inhibition Effect of Alkaline Conditions on the Inactivation

“…In Figure a, the binding energy of Ag 3d after the sixth cycle shows a 0.2 eV increase. According to the literature, the binding energy of Ag 0 is slightly higher than that of Ag + , thus the increased binding energy suggests the formation of metallic Ag . In Figure b, the binding energy of O 1s is increased after the six reactions.…”

“…According to the literature, the binding energy of Ag 0 is slightly higher than that of Ag + , thus the increased binding energy suggests the formation of metallic Ag. 27 In Figure 6b, the binding energy of O 1s is increased after the six reactions. Xu et al have reported that the binding energy of organic O, such as C−O, C�O, C−OH, O−C�O, is greater than that of inorganic O.…”

“…High-resolution transmission electron microscope (HRTEM) images of the nanoparticles are shown in Figure 2b, where the crystal plane spacing of 0.352 nm matches the plane {101} of anatase-TiO 2 , while the crystal plane spacing of 0.236 nm corresponds to the plane {200} of cubic-Ag 2 O. 26,27 These results demonstrate that the prepared Ag 2 O/TiO 2 composite comprises both cubic-Ag 2 O and anatase-TiO 2 with high crystallinity and a heterogeneous structure.…”

Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe3O4@TiO2 Ternary Nanocomposites for Dye Degradation and H2 Production under Light and Dark Conditions

“…35 Similarly, it was observed that the Ag 3d 5/2 peak could also be deconvoluted into two peaks at 367.5 and 368.2 eV, respectively, revealing the existence of Ag 2 O and Ag 0 metallic silver. 36,37 The presence of Ag 2 O could be possibly due to the surface oxidation of the Ag nanoparticles after deposition. However, the firm existence of the metallic nature of Ag can also be corroborated with its XRD pattern, as shown in Figure 1(a) and (b).…”

Raspberry-like TiO2 hollow spheres consisting of small nanocrystals towards efficient NO removal

“…Among various photocatalysts, TiO 2 has attracted much attention because of its high photocatalytic stability, low cost, and it being harmless to the human body. 17,18 However, TiO 2 nanocrystals inevitably agglomerate to affect the light utilization and reduce photocatalytic efficiency. 19,20 An effective method to improve the specific surface area of photocatalysts and reduce the agglomeration degree is by assembling TiO 2 nanocrystals into different morphologies.…”