Performance of γ-Ga2O3-Al2O3 solid solutions prepared by spray pyrolysis for CH4-SCR of NO

Precursor particles for γ-Ga2O3-Al2O3 solid solutions were prepared by spray pyrolysis of aqueous solutions of mixtures of Ga(NO3)3, Al(NO3)3, and HNO3, and the performance of the γ-Ga2O3-Al2O3 solid solutions obtained by calcination thereof at 800 °C was investigated for the selective catalytic reduction of NO with methane as a reducing agent. The precursor prepared with a temperature gradient from 200 to 700 °C and with a total residence time of 23 s in the ovens had a high performance. The concentration of HNO3 or of metal nitrates affected the performance. The precursor prepared from Al(NO3)3 or Al(acac)3 as an aluminum source exhibited high performance; however, the precursor prepared from pseudoboehmite resulted in a lower activity.

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► Precursor particles for γ-Ga2O3-Al2O3 solid solutions were prepared by spray pyrolysis.
► An adequate temperature in ovens and residence time for the mists in spray pyrolysis were required.
► The concentration of HNO3 or of metal nitrates in the starting solution affected the performance.