Photoluminescence of propylene adsorbed on γ-Ga 2O 3-Al 2O 3 solid solutions in relation to their catalysis for CH 4-SCR of NO

Abstract

When a solvothermally prepared γ-Ga 2O 3-Al 2O 3 (Ga 30 mol%) catalyst was treated with C 3H 6 followed by heating at 523 K, it colored yellow [J. Catal. 259 (2008) 36]. The photoluminescence (PL) spectra of the colored species showed two bands at near ultraviolet (383 nm) and blue-green (487 nm) regions under excitation at 343 nm, and a blue-green band (491 nm) under excitation at 436 nm. The former emissions were attributed to the carbenium ions on the tetrahedral Ga 3+ sites in γ-Ga 2O 3-Al 2O 3, and the latter, to those on the octahedral Ga 3+ sites. The band intensity at 383 nm increased by heating the C 3H 6-loaded catalyst upto 523 K and further increase in temperature decreased the band intensity. The intensity of the emission band at 383 nm linearly correlated with the catalytic activity of γ-Ga 2O 3-Al 2O 3 for selective catalytic reduction of NO with CH 4.