Effect of RhOx/CeO2 Calcination on Metal-Support Interaction and Catalytic Activity for N2O Decomposition

Abstract

Abstract:The effect of the calcination conditions on the catalytic activity for N2O decomposition of 2.5% RhOx/CeO2 catalysts has been investigated. Ramp and flash calcinations have been studied (starting calcinations at 25 or 250/350 °C, respectively) both for cerium nitrate and ceria-impregnated rhodium nitrate decomposition. The cerium nitrate calcination ramp has neither an effect on the physico-chemical properties of ceria, observed by XRD, Raman spectroscopy and N2 adsorption, nor an effect on the catalysts performance for N2O decomposition. On the contrary, flash calcination of rhodium nitrate improved the catalytic activity for N2O decomposition. This is attributed to the smaller size of RhOx nanoparticles obtained (smaller than 1 nm) which allow a higher rhodium oxide-ceria interface, favoring the reducibility of the ceria surface and stabilizing the RhOx species under reaction conditions.

Dry reforming of glycerol over Rh-based ceria and zirconia catalysts: New insights on catalyst activity and stability

“…6a belongs to the fresh RhZr catalyst. The feature at 173 cm −1 can be attributed to RhO x species [60][61][62]. This observation is in line with the in-situ FTIR data given in Fig.…”

“…These defects can either originate from Rh incorporation into the ceria lattice due to strong metal support interaction between Rh particles and the reducible CeO 2 lattice [70][71][72][73][74] or from the reduction of ceria with hydrogen which was used during the routine activation protocol of the fresh catalysts after synthesis. Moreover, another weak feature appearing at 167 cm −1 for the Raman spectrum of the fresh RhCe catalyst can be due to the defects in the ceria lattice or possibly to Rh-O-Ce and/or RhO x species [60][61][62]72,73].…”

Effect of MO2 (M = Ce, Mo, Ti) layer on activity and stability of PtCo/C catalysts during an oxygen reduction reaction

“…Three types of commercial metal oxides, including TiO 2 (P25 Degussa, Sigma-Aldrich), MoO 2 (Sigma-Aldrich) and the asprepared CeO 2 , prepared by the calcination of Ce[NO 3 ] 3 Á6H 2 O (Sigma-Aldrich) at 600°C for 90 min [27] were used in this study. To incorporate commercial TiO 2 and CeO 2 on the catalyst layer at different loadings of 0.03, 0.06, 0.15, 0.30 and 0.45 mg/cm 2 , 0.4, 0.8, 1.5, 3.0 and 5.0 mg of either TiO 2 or CeO 2 were mixed with 6 mL of i-propanol and sonicated 15 min at ambient temperature.…”

Direct Observation of Rhodium Ex-Solution from a Ceria Nanodomain and Its Use for Hydrogen Production via Propane Steam Reforming

“…A shoulder at higher temperatures of ∼260 °C was ascribed to the reduction of Rh located at the lattice of CeO 2 in the solid solution. On the other hand, the surface oxide on the 4Rh/CeO 2 showed the reduction peak at the lower temperature of 75 °C, indicating that ex-solved Rh nanoparticles have more SMSI than Rh nanoparticles on the Rh/CeO 2 . − …”