Niobia and silica–niobia catalysts from sol–gel synthesis: an X-ray photoelectron spectroscopic characterization

Effect of Nb content on hydrothermal stability of a novel ethylene-bridged silsesquioxane molecular sieving membrane for H2/CO2 separation

“…While a reverse tendency was apparent for the peak at 532.2 eV. It can be concluded [55,73,74] that the proportion of Nb-O bridge amounts increased, while O-Si siloxane bridge amounts decreased with the niobium loading based on the calculated area under the corresponding peak and increased FWHM (Full width at half maximum) of O 1s peak, as also evidenced by the XPS results shown in Table 1. To make sure that more Nb-O-Si and/or Nb-O-Nb bridges are formed as Nb incorporated into BTESE powders, solid state 29 Si MAS NMR spectrum was used to qualitatively determine the silanol groups presented in BTESE and NS-2 powders, which on one hand could determine the degree of polymerization by using BTESE and NPB as precursors.…”

“…Also shown the inset of Fig. 6(a) are the Nb(3d) XPS spectra of NS-2 and NS-4 powders, which suggested that both samples produced a single symmetric 3d 5/2 component which, on the basis of its binding energy (207.870.2 eV), can be assigned to Nb(V) [73,69]. Table 1 shows the elemental composition analysis of NS-2 and NS-4 powders by XPS characterization.…”

The Fabrication of Ga2O3/ZSM-5 Hollow Fibers for Efficient Catalytic Conversion of n-Butane into Light Olefins and Aromatics

“…According to the Ga 2p 3/2 XPS spectra (Figure 2), the Ga 2p 3/2 binding energy value (BEs) for the as-prepared Ga/ZSM-5 (1118.3 eV) is consistent with that for Ga 2 O 3 , indicating that the gallium exists on the surface of ZSM-5 in the form of Ga 2 O 3 . In comparison with that of the single bulk Ga 2 O 3 , the broadening of the half peak width of Ga 2p 3/2 of the as-prepared Ga 2 O 3 /ZSM-5 occurs, which is connected with the increase of the Ga dispersion [32]. Figure 3A shows the SEM image of the synthesized Nano-ZSM-5 with the average particle size of 137 nm.…”

Oxidation of geraniol using niobia modified with hydrogen peroxide

“…Figures 3a and 3b illustrate the deconvolution curves of O 1s and Nb 3d core levels. The Nb 3d spectra (Figure 3a) were deconvoluted using triplet lines attributed to N b +5 phases [19,20]. The binding energy of Nb 3d 5/2 and Nb 3d 3/2 lines was equal to 206.6 and 209.2 eV, respectively, with accuracy of ± 0.1 eV.…”

“…It is indicated that the peroxo group formation could be observed analyzing the region between 500 -540 eV in the XPS spectrum [4,15,20]. They found that the peak around 532 eV was not observed for the commercial or synthetized N b 2 O 5 sample [4,19]. There are two views about XPS of niobium oxides data in the literature.…”