N-doped TiO₂/C nanocomposites and N-doped TiO₂ synthesised at different thermal treatment temperatures with the same hydrothermal precursor

Abstract

A hydrothermal precursor was first obtained by isopropyl titanate reacting with tetramethylammonium hydroxide (TMAOH), which acts as a source of nitrogen and carbon. A facile post-thermal treatment was employed to enhance the crystallinity and visible light photocatalytic activity of the as-prepared precursor. The resulting products of post-thermal treatment between 200 °C and 700 °C display different colours from brown to white. Black N-doped TiO2 nanoparticles modified with carbon (denoted as N-TiO2/C) were obtained at 300 °C, while yellow N-doped TiO2 nanoparticles (denoted as N-TiO2) were obtained at 500 °C. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were applied to characterize N-TiO2/C, N-TiO2 and the evolution process during thermal treatment. The results show that for both N-TiO2/C and N-TiO2, nitrogen was doped into the lattice, thus narrowing the band gap and increasing the absorption in the visible light region. Moreover, for N-TiO2/C, the carbon species modified on the surface and between the nanocrystals enhanced the visible light harvesting and increased the adsorption of the dye in the photodegradation measurement. The photocatalytic performance under visible light irradiation is N-TiO2/C > N-TiO2 > undoped TiO2.

Synthesis, characterisation and photocatalytic activity of N-doped TiO2–Nb2O5 mixed oxides

“…According to Herrmann [43], a correct improvement in catalysis requires a benefit by at least a factor of two, or even better by one order of magnitude. This fact provides a further confirmation of what should be expected based on literature results [44].…”

Hybridizing TiO2 with Nitrogen‐Doped Carbon: A New Route to A Highly Visible Light‐Active Photocatalyst

“…No peak shift of Ti 2p 3/2 and Ti 2P 1/3 is observed, comparing N‐doped C/TiO 2 with Meso‐TiO 2 . The peak at 281.0 eV assigned to Ti−C bond and the binding energy of Ti−N at 397 eV are not observed, which indicates that there is no lattice incorporation of nitrogen or carbon to form Ti−N or Ti−C in our study . Besides, a curve fitting analysis of O 1 s XPS spectra (Figure b) shows that two peaks at 529.8 and 532.1 eV are ascribed to the O 1 s in the Ti−O linkages of TiO 2 and that in Ti‐O−N, respectively .…”

Promoting Effect of Bismuth Oxide on Palladium for Low‐Temperature Carbon Monoxide Oxidation

“…[34] In addition, the XPS peaks at BE = 156.8 and 162.1 eV are assigned to metallicB i4f 7/2 and 4f 5/2 (18 %) and the peaks at BE = 158.7 and 164.0 eV are assigned to Bi 4f 7/2 and 4f 5/2 of Bi 2 O 3 (82 %; Figure 4B). [35][36][37] In the Ti 2p XPS spectra shown in [19,39,40] Notably,t he Pd 3p 3/2 peak (BE % 532.8 eV) overlaps with the O1sp eaks. An additional peak at BE = 532.4 eV is ChemCatChem 2017, 9,499 -504 www.chemcatchem.org observedf or Pd&Bi(1.4)/TiO 2 -N, which may be caused by the surfaceo xygen speciesr elatedt oP da nd Bi interfaces.…”

“…These changes could be caused mainly by metal–metal oxide interactions. The O 1s spectra of TiO 2 ‐N, Pd/TiO 2 ‐N, and Pd&Bi(1.4)/TiO 2 ‐N are shown in Figure D. The peaks at BE=529.6 eV can be ascribed to the lattice O atom of TiO 2 , whereas the peak at BE=531.4 eV can be assigned to the OH group on the TiO 2 surface . Notably, the Pd 3p 3/2 peak (BE≈532.8 eV) overlaps with the O 1s peaks.…”