Interfacial effects of MnO_x-loaded TiO₂ with exposed {001} facets and its catalytic activity for the photoreduction of CO₂

Abstract

The percentage of the exposed facets affect the interface connection between the semiconductor and the cocatalysts, leading to different separation rates of carriers.

Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

“…It has been believed that DAPs exposing two {001} and eight {101} facets have a high level of photocatalytic activity because photoexcited electrons and positive holes migrate to the {101} and {001} facets, respectively, resulting in efficient charge separation [12][13][14][15][16][17][18][19][20][21][22][23]. However, since such "charge separation" cannot be observed directly as mentioned above, the reason seems to be just speculation or a hypothesis proposed on the basis of microscopic observations of metal-and metal oxide-deposited DAPs through photocatalytic reduction and oxidation from their precursors on {101} and {001} facets, respectively [12][13][14][15][16][17][18][19][20].…”

Photocatalytic Fixation of Nitrogen to Ammonia by Single Ru Atom Decorated TiO2 Nanosheets

“…In the Ru 3p 3/2 XPS spectra, the peak at about 531.6 eV likely originated from RuO x due to oxidation of Ru after exposure to air . An additional peak centering at 533 eV was also identified, possibly assigned to surface H 2 O (adsorbed oxygen) because of the strong hydrophilicity of oxygen vacancies . Moreover, density functional theory (DFT) calculations were performed to explain the stability of Ru atoms on the surface TiO 2 nanosheets.…”

“…39 An additional peak centering at 533 eV was also identified, possibly assigned to surface H 2 O (adsorbed oxygen) because of the strong hydrophilicity of oxygen vacancies. 40 Moreover, density functional theory (DFT) calculations were performed to explain the stability of Ru atoms on the surface TiO 2 nanosheets. All results are based on perfect and defective TiO 2 (001) surface structures.…”

“…In contrast, the top of the VB of TR-1.0 was shifted to 2.48 eV probably arising from the increase in the upward band bending as a result of interaction between TiO 2 and Ru. 40,43,44 UV−vis spectroscopy revealed that the Ru loaded TiO 2 nanosheet photocatalysts exhibited a wider absorption range than pure TiO 2 nanosheets (Figure 3D). The absorption edges of TiO 2 -NS, TR-0.1, TR-0.5, TR-1.0, and TR-2.0 were at 390, 399, 408, 433, and 446 nm, respectively.…”

Investigation of process parameters assessment via design of experiments for CO2 photoreduction in two photoreactors

“…For example, photocatalysts modification is one of the pursued strategies, where several semi-conductors have been investigated, including CdS [5][6][7], ZnO [8][9], ZrO2 [10], WO3 [11], SrTiO3 [12], although TiO2 remains the most investigated and promising material [13][14][15]. Another strategy to increase photoactivity is materials modification, aimed at suppressing electron-hole recombination, which can be pursued in several ways: use of co-catalyst [16][17][18][19], metal doping [20], graphene encapsulation [21]; but one of the most promising options is the introduction of surface plasmonic resonance particles [21][22][23][24]. Material engineering aside, reactor design and catalytic conditions for CO2 photoreduction still need to be further investigated and standardised to compare materials photoactivity significantly.…”