Insights into flower-like Al2O3 spheres with rich unsaturated pentacoordinate Al3+ sites stabilizing Ru-CeOx for propane total oxidation

Herein, a series of nano-flower sheet-like alumina spheres (NF-Al2O3) with rich unsaturated pentacoordinate Al3+ sites stabilizing Ru-CeOx catalysts were designed and synthesized for catalytic total oxidation of one typical light alkanes (propane, C3H8). The 90 % conversion temperature (T90) and the apparent activation energy (Ea) of Ru-Ce7/NF-Al2O3 modified by 7 wt.% of CeO2 were as low as 207 °C and 56.7 kJ mol−1, respectively. In addition, it also exhibited superior water, sulfur and carbon dioxide resistance and recycling performance. The excellent catalytic performance of propane total oxidation over Ru-CeOx/NF-Al2O3 is mainly attributed to NF-Al2O3 has rich unsaturated pentacoordinate Al3+ sites can anchor the Ru-CeOx active species. The anchoring effect of Al3+penta on the metal active unit can effectively promote the dispersion of Ru-CeOx active species and stabilize the electronic valence state of Ru0. The degradation of C3H8 over Ru-CeOx/NF-Al2O3 conformed to the Mars-van-Krevelen mechanism through two different pathways as revealed by the in situ DRIFTS.