The active role of CO2 at low temperature in oxidation processes: the case of the oxidative dehydrogenation of propane on NiMoO4 catalysts

Oxidative dehydrogenation of -butane over nanostructured silica-supported NiMoO catalysts with low content of active phase

“…This result agrees with the recent findings of Dury et al [39]. In fact these authors stated that CO 2 in reaction mixture can have a beneficial effect on the catalytic behaviour since it can be dissociatively adsorbed on the catalysts surface acting as a powerful oxidant.…”

High throughput experimentation applied to the combustion of methane and a comparison with conventional micro-reactor measurements

“…After reaction in the presence of CO 2 , enrichment in low BE O 1s species was observed suggesting that, on Pd/Ce-Zr-O samples, some oxygen species might be formed in the presence of CO 2 [10]. These oxygen species would come from the dissociative adsorption of CO 2 on the surface, as it has been previously largely discussed [11]. It is suggested that this oxygen species could help to keep catalysts in a more oxidized state, improving the catalytic activity [6].…”

CO2 as an Oxidant for High-Temperature Reactions

“…Thus in these works, CO 2 acted as a modulator of the oxidative properties of oxygen (Dury et al, 2003a;Park and Ansari, 2013). Among the advantages of CO 2 introduction in the system are lower tendency for hydrocarbons combustion (whilst minimizing hot spot formation) and decrease in coking effect (Dury et al, 2003b).…”

“…For example, in a Mo 2 C/SiO 2 system, by co-feeding CO 2 for the ODH reaction, the benefits of CO 2 in oxidizing the Mo 2 C forming Mo-oxycarbide at higher temperatures could be observed (Solymosi and Nemeth, 1999;Solymosi et al, 2001). In fact, Dury et al, 2003a) reported that dissociation of CO 2 on the catalyst surface could take place due to introduction of 3% CO 2 for the ODH reaction of propane over NiMoO 4 hence inducing the oxidation of molybdenum suboxide at temperatures around 673-723 K. The presence of both molybdates and molybdenum oxides can enhance the catalytic properties of NiMoO 4 in hydrocarbon oxidation (Lezla et al, 1997;Dury et al, 2003a). CO 2 dissociation results in formation of oxygen species that have higher selectivity compared to molecular oxygen and radical formation can be avoided.…”