Bimetallic Ru-Re/γ-Al2O3 catalysts for the catalytic combustion of propane: Effect of the Re addition

• Bimetallic Ru-Re/γ-Al2O3 catalysts have been tested in the propane combustion.
• The addition of rhenium up to 3 wt.% improved the catalytic activity of the Ru phase.
• Rhenium significantly suppressed Ru particle sintering in the Ru-Re catalysts.

The combustion of propane over bimetallic Ru-Re/γ-Al2O3 catalysts with the Ru/Re atomic ratio of 90/10, 75/25 and 50/50 has been investigated. The catalysts were synthesized by co-impregnation method using Ru(NO)(NO3)3 and NH4ReO4 as metal precursors. Techniques such as H2-TPR, XRD, SEM, TEM, XPS and O2 adsorption were used to characterize the catalysts. All the bimetallic catalysts contained highly dispersed RuRe alloy nanoparticles (<3 nm) and at Ru/Re = 50/50 also Re particles (∼8 nm). The catalysts with the Ru/Re atomic ratio 90/10 and 75/25 (Re loading ≤ 3 wt.%) exhibited higher activity in the propane combustion than the Ru catalyst. The improvement of the activity was related to better reducibility of the metal oxide species and higher dispersion of an active RuOx phase. The catalyst with the Ru/Re atomic ratio of 50/50 (Re loading of 9.2 wt.%) exhibited lower activity because the ruthenium phase was partly blocked by inactive ReOx species. The addition of Re significantly suppressed Ru particle sintering in the Ru-Re/γ-Al2O3 catalysts. This causes that deactivation of the bimetallic Ru-Re catalysts under O2-rich reaction conditions was significantly lower than that of the monometallic Ru/γ-Al2O3 catalyst.

Combustion of propane over Ru/γ-Al2O3 and bimetallic Ru-Re/γ-Al2O3 catalysts.Figure optionsDownload high-quality image (129 K)Download as PowerPoint slide