Evaluation of catalytic activity of Ga 2O 3–Al 2O 3 solid solutions for CH 4-SCR by UV–vis spectra after adsorption of C 3H 6 as a probe

Abstract

When γ-Ga 2O 3–Al 2O 3 solid solutions were treated with C 3H 6 followed by heating at 300 °C, they were colored yellow giving two bands at 340 nm ( α band) and 430 nm ( β band) in their UV–vis spectra. The α and β bands were closely related with surface tetrahedral ( T d )-Ga 3+ and octahedral ( O h )-Ga 3+ sites, respectively. The intensities of the two bands changed by γ-Ga 2O 3–Al 2O 3 solid solutions prepared by various methods, although they had almost the same proportions of T d -Ga 3+ sites in the bulk structure. The intensities of the two bands can be used to diagnose the catalytic activity of γ-Ga 2O 3–Al 2O 3 catalysts for CH 4-SCR of NO.