* Chemical transformation: organic chemical synthesis, methanation, hydrogenation (methanol), reforming: dry (CO\({}_{2}\)) or steam reforming (CO\({}_{2}\) + H\({}_{2}\)O);
* Biological transformation: microalgae, biocatalysis. However, the CO\({}_{2}\) valorization process requires a gas as pure as possible [2]. Oxyfuel-combustion is, therefore, a promising method to obtain a nearly pure CO\({}_{2}\) that enables a CO\({}_{2}\) rich stream (80%) to be obtained [3]. In the oxyfuel system, the combustion flow consists of pure O\({}_{2}\) obtained by air distillation. By excluding dinitrogen from the oxidizing flow, the production of NOx is limited as well as the amount of smoke generated. This NOx emission limitation is interesting as NOx are considered as one of the main pollutants of the atmosphere, since they are responsible for a lot of environmental problems like photochemical smog, acid rain, and ozone layer depletion [4]. This process emits also water vapor, unburned components (in function of the waste burned) such as carbon monoxide (generated by incomplete combustion) in addition to nitrogen monoxide [3]. CO is the cheapest and the most available compound from industrial sources and it could be used as a reductant of NO although it is known to be one of the worst reductants. [PERSON] ranked several reducers according the NO half-conversion temperatures achieved using noble metals. The sequence obtained is as follows: H\({}_{2}\) > NH\({}_{3}\) > CO > C\({}_{3}\)H\({}_{5}\)[5]. So it seems possible to purify the CO\({}_{2}\) issued from oxyfuel-combustion by the NO-CO reaction which consists of the main challenge that our work tried to address. In oxyfuel combustion systems, NO, CO, O\({}_{2}\) are simultaneously present and the following reactions may occur [6]:  
\[2\;\text{NO}+2\;\text{CO}\rightarrow\text{N}_{2}+2\;\text{CO}_{2}\]  
\[2\;\text{CO}+\text{O}_{2}\rightarrow\text{2\;CO}_{2}\]  
Therefore, as oxygen is present in excess, it competes with NO for oxidizing the reducing agent (CO) [7]. Due to this effect, many authors studied the competitions between CO-NO and CO-O\({}_{2}\) reactions. [PERSON] et al. demonstrated that the second reaction is predominant over a number of transition metal oxides and supported Pt [8]. Other authors proved that the NO addition to CO + O\({}_{2}\) mixture reduces drastically the rate of CO\({}_{2}\) formation on Rh catalyst [9] and Pt supported catalyst [10]. The NO-CO reaction has been widely applied and investigated over various catalysts. For example, three-way catalysts (TWC), composed of noble metals (Rh, Pd and Pt), convert CO, NO, and hydrocarbons simultaneously [11]. Rh is employed for NO removal because it combines a good activity and selectivity to form nitrogen [12]. On the other hand, Pt and Pd ensure the oxidation of CO and hydrocarbons [13]. [PERSON] and [PERSON] [14] studied NO reduction over supported Pt, Rh, Pd and Ru. They proved that, when CO is used as reducing agent, the reaction over the Ru catalyst is accelerated. The activity sequence of the catalysts was: Ru > Rh > Pt > Pd. Ir was also studied for this reaction in the presence of O\({}_{2}\)[7,15]. It has been demonstrated that Ir effectively promotes the NO-CO reaction in the presence of an excess of oxygen. To summarize, the objective is to reduce NO by CO in an oxidizing environment with a CO\({}_{2}\) rich stream in order to purify the latest without the use of a SCR (selective catalytic reduction) system that would switch to a reductive atmosphere by injecting additives (ammonia or urea) [11]. The important amount of CO\({}_{2}\) could be a problem for materials with basic properties due to carbonate species formation. Alumina was then chosen because of its strong Lewis acid centers which ensure the stabilization of species in active state and disperses them adequately, as well as its intrinsic catalytic activity in various reactions [13,16].