Visible-light photocatalytic activity of NH 4 NO 3 ion-exchanged nitrogen-doped titanate and TiO 2 nanotubes

Souza, Juliana S.; Pinheiro, M. V. B.; Ando, Rômulo Augusto; Guha, S.; Alves, Wendel A.

doi:10.1016/j.molcata.2014.06.036

Cited by 24 publications

(20 citation statements)

References 47 publications

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“…The Ti 3+ species from NTs are observable through the resonance signal with g values close to 2.0, as found elsewhere [ 42 , 43 ]. Moreover, the paramagnetic defects of the foreign species are embedded in the titanate nanotubes structure possessing a lower symmetry [ 44 ]. For, AgNT ( Figure 5 a), two isotropic bands doublet signals at around 2500 and 3200 G are ascribable to the isolated Ag + ions and Ag coordinated to oxygen on the NTs surface [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

et al. 2021

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Effects of the incorporation of Cr, Ni, Co, Ag, Al, Ni and Pt cations in titanate nanotubes (NTs) were examined on the NOx conversion. The structural and morphological characterizations evidenced that the ion-exchange reaction of Cr, Co, Ni and Al ions with the NTs produced catalysts with metals included in the interlayer regions of the trititanate NTs whereas an assembly of Ag and Pt nanoparticles were either on the nanotubes surface or inner diameters through an impregnation process. Understanding the role of the different metal cations intercalated or supported on the nanotubes, the optimal selective catalytic reduction of NOx by CO reaction (SCR) conditions was investigated by carrying out variations in the reaction temperature, SO2 and H2O poisoning and long-term stability runs. Pt nanoparticles on the NTs exhibited superior activity compared to the Cr, Co and Al intercalated in the nanotubes and even to the Ag and Ni counterparts. Resistance against SO2 poisoning was low on NiNT due to the trititanate phase transformation into TiO2 and also to sulfur deposits on Ni sites. However, the interaction between Pt2+ from PtOx and Ti4+ in the NTs favored the adsorption of both NOx and CO enhancing the catalytic performance.

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Section: Resultsmentioning

confidence: 99%

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

et al. 2021

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“…Titanate nanotubes were prepared using an alkaline hydrothermal process according to the literature with minor modifications 54,55 . ZnONR and ZnONR+gly films.…”

Section: Reactantsmentioning

confidence: 99%

Multihierarchical electrodes based on titanate nanotubes and zinc oxide nanorods for photoelectrochemical water splitting

et al. 2016

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a Studies involving water splitting to form hydrogen and oxygen have attracted attention because H2is considered the fuel of the future. Photoelectrocatalysts have been widely used for this application, and several metal oxides can be applied as catalysts. Among them, we highlight zinc oxide nanorods (ZnONRs) and titanate nanotubes (TiNTs); however, their individual nanostructures exhibit disadvantages. For example, ZnONR shows rapid recombination of the photogenerated charges, and TiNT gives rise to randomly orientated films; these disadvantages limit their application as photoanodes. In this study, for the first time, we present a new class of multihierarchical electrodes based on TiNT-decorated ZnONR films that exhibited superior results to the individual species. The TiNTs are homogenously dispersed over the surface of the rods without forming agglomerates, giving rise to a heterojunction that exhibits lower recombination rates. It was found that the results are better when the contents of TiNT in the electrode are higher; thus, glycine was successfully used as a bridge to link both of the structures, increasing the amount of TiNT decorating the rods. As a result, the photocurrent generated with these multihierarchical electrodes is higher than that obtained for pure ZnONR electrodes (0.9 mA and 0.45 mA, respectively), and the electrode potentials for O2 evolution is lower than that observed for pure TiNT electrodes (0 V and 0.8 V vs. ERHE, respectively). The IPCE values are also higher for the multihierarchical electrodes.

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“…In Fig. 3, bands characteristic for the niobium-oxygen bond can be seen, such as the band between 600-700 cm -1 , corresponding to angular vibrations of Nb-O-Nb, another at ∼880 cm -1 , corresponding to stretches of the Nb-O and the band located around ∼950 cm -1 that might be associated with surface Nb− −O stretches [43][44][45]. Although the data are not shown, the integrated area was calculated for the band between 600 and 700 cm -1 and the results showed an increasing tendency of Nb-O-Nb peak intensity as the pH of the system increased, indicating that the presence of large quantities of OHgroups in the system would strengthen the Nb-O-Nb bond.…”

Section: Characterization Of Dried Powdersmentioning

confidence: 97%

The effect of the synthesis conditions on structure and photocatalytic activity of Nb2O5 nanostructures

Daza-Gómez

Páez

2018

PAC

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In this work, niobium pentoxide (Nb 2 O 5) nanoparticles of varying sizes and morphology were synthesized using the controlled precipitation method. Ammonium niobate oxylate hydrate (NH 4)H 2 [NbO(C 2 O 4) 3 ] • 3 H 2 O was used as a niobium precursor and distilled water or acetic acid was used as solvent. The obtained solids were characterized using Fourier transform infrared and Raman spectroscopies, X-ray diffraction and transmission electron microscopy. The as-synthesized solid precipitate was amorphous, but after heat treatment between 500°C and 600°C, the T-Nb 2 O 5 phase was obtained. The size of the primary particles of the niobium pentoxide was nanometric (<100 nm), with agglomerate size of >500 nm, when water was used as a solvent for synthesis. Considering the nature of the process, a possible reaction mechanism of the precursor with the water and NH 4 OH was proposed, which explains the formation of the solid within an aqueous solution. Considering one potential use of Nb 2 O 5 synthesized in this work, the photo-degradation action of the particles on the organic molecule methylene blue was tested. The sample synthesized in acetic acid at pH ∼9.0 and heat treated at 600°C showed the highest photo-degradation capacity, with a degradation of ∼60% of the dye for 60 minutes.

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Visible-light photocatalytic activity of NH 4 NO 3 ion-exchanged nitrogen-doped titanate and TiO 2 nanotubes

Cited by 24 publications

References 47 publications

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

Multihierarchical electrodes based on titanate nanotubes and zinc oxide nanorods for photoelectrochemical water splitting

The effect of the synthesis conditions on structure and photocatalytic activity of Nb2O5 nanostructures

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