TY - JOUR

T1 - CHF3 as a probe for surface basicity

AU - Tsyganenko , AA

AU - Zakharov , NV

AU - Murzin , PD

PY - 2014

Y1 - 2014

N2 - FTIR spectra of adsorbed fluoroform as a test for surface basicity have been studied on a number of oxides and zeolites. CHF3 does not dissociate even on strongest basic sites, and forms H-bond with considerable stretching CH frequency lowering. With weaker basic oxygen atoms it demonstrates the blue-shifting H-bond accompanied by CH band intensity decrease and a high frequency shift of bending vibrations. Dependence of the frequency and integrated absorption coefficient of CH stretching vibration on the strength of H-bond is discussed. The problem of basicity testing can be solved by using two different probe molecules for sites of various strength. While fluoroform is good for stronger sites, weak sites can be tested by pyrrole, acetylene or its derivatives that are more sensitive, but dissociate on the most basic oxygen centers.

AB - FTIR spectra of adsorbed fluoroform as a test for surface basicity have been studied on a number of oxides and zeolites. CHF3 does not dissociate even on strongest basic sites, and forms H-bond with considerable stretching CH frequency lowering. With weaker basic oxygen atoms it demonstrates the blue-shifting H-bond accompanied by CH band intensity decrease and a high frequency shift of bending vibrations. Dependence of the frequency and integrated absorption coefficient of CH stretching vibration on the strength of H-bond is discussed. The problem of basicity testing can be solved by using two different probe molecules for sites of various strength. While fluoroform is good for stronger sites, weak sites can be tested by pyrrole, acetylene or its derivatives that are more sensitive, but dissociate on the most basic oxygen centers.

U2 - 10.1016/j.cattod.2013.11.049

DO - 10.1016/j.cattod.2013.11.049

M3 - Article

VL - 226

SP - 73

EP - 80

JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

ER -