Table 1 Surface textural properties and acid sites content of the niobium oxides

From: Niobium pentoxide nanomaterials with distorted structures as efficient acid catalysts

Sample

SBET (m2 g−1)a

Vads (cm3 g−1)b

Vmesop (cm3 g−1)c

dp (nm)d

AST (mmol g−1)e

Brønsted (mmol g−1)f

Lewis (mmol  g−1)g

Nb2O5-NP

196

0.16

0.06 (53)

2.7

0.75 (3.83)

0.187

0.197

Nb2O5-NS

352

0.24

0.15 (48)

2.8

1.10 (3.12)

0.263

0.221

Nb2O5-hGO

256

0.28

–

3.1

0.90 (3.52)

–

–

Nb2O5·nH2O

285

0.15

0.14 (5)

2.6

0.55 (1.93)

0.155

0.144

  1. aBET specific surface area
  2. bVolume adsorbed at P/P0 = 0.98
  3. cVolume of mesopores determined by the t-plot (the external surface areas to the mesopores, in m2 g−1, are shown in parentheses)
  4. dMaximum of the pore size distribution
  5. eTotal amount of acid sites determined by liquid-phase titration (the amounts of acid sites per unit surface, in μmol m−2, are given in parentheses)
  6. f,gAmounts of Brønsted and Lewis acid sites determined by FT-IR of adsorbed pyridine, respectively
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