## 1 Introduction  
Cerium dioxide powders have potential applications in polishing powders, coatings for high-temperature optical and ceramic materials, gas sensors, catalysts for environmental processes like Three Way Catalyst (TWC), wet catalytic oxidation of organic pollutants (removal of organics from wastewaters), water gas shift (WGS) reaction, CO oxidation, combustion processes or in solid oxide fuel cell technology [1,2]. The interest of ceria-based materials is related to their structural and chemical properties, low temperature reducibility, oxygen storage capacity, and oxygen release properties among others.  
In catalytic applications, ceria is used either as metal support or as catalyst itself [1,3]. The use of ceria as noble metal support has attracted intense interest due to their vast applications in heterogeneous catalysis. Many factors, including the size and distribution of the noble metal particles, the surface morphology and defects on the oxides, affect the performance of noble metal/ceria catalysts. Indeed, effectively controlling the size of noble metal particles is crucial for maintaining high catalytic activity. The behavior of the metal-oxide interface, which can be quite dynamic, as exemplified by the well-known strong metal-support interaction (SMSI), is of critical importance in this regard [1, 2, 3, 4, 5].  
The promoting effect of CeO\({}_{2}\)-based materials in the catalytic activity of rhodium, and other platinum group metals (PGM), is very well known for several chemical reactions [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], like in three-way catalysts (TWC) where NOx, hydrocarbons and CO are simultaneously depleted [16].  
N\({}_{2}\)O decomposition on ceria-supported noble metal catalysts was investigated in a previous work, where noble metals (Rh, Pd and Pt) were supported on \(\gamma\)-Al\({}_{2}\)O\({}_{3}\), pure CeO\({}_{2}\) and La- and Pr-doped CeO\({}_{2}\)[17]. Rh was the best noble metal, and the support strongly affected the activity, ceria-based supports being better as rhodium support than alumina. In a further study [18], the Rh/Ce\({}_{0.9}\)Pr\({}_{0.1}\)O\({}_{2}\) active phase was supported on a cordiertic monolith, and one of the conclusions reported was that the calcination procedure affects the Rh-Ce-Pr interactions and the homogeneous distribution of the active phases on the substrate. It was observed that catalysts prepared by flash calcinations, consisting of introducing the monolith impregnated with metal precursor salts in a previously heated furnace, are more active for N\({}_{2}\)O decomposition than the counterpart catalysts calcined by a conventional ramp heating. Flash calcination improved the homogeneous distribution of the active phase on the substrate and smaller rhodium particles were obtained by this procedure, improving the reduction of surface Rh-Ce-Pr entities at low temperature. However, it was not possible to analyze the effect of the calcination rate on the active phase properties due to the low mass of active phase with regard to the mass of cordiertic support. The improved activity of RhOx/Ceria catalysts prepared by flash calcination was also demonstrated for the CO oxidation reaction [19]. Nevertheless, a detailed study of the effect of the calcination rate both of the ceria support and of the rhodium nitrate, starting calcination at different temperatures, has never been reported for N\({}_{2}\)O decomposition RhOx/ceria catalysts.  
The goal of this study is to get further insights into the effect of the calcination conditions on the metal-support interaction and catalytic activity for N\({}_{2}\)O decomposition of RhOx/CeO\({}_{2}\) catalysts. For this purpose, powder catalysts have been prepared following different ramp and flash calcination conditions, analyzing the effect on the physico-chemical properties and catalytic activity for N\({}_{2}\)O decomposition of the resulting model RhOx/CeO\({}_{2}\) catalysts.