Surface oxygen vacancy vs oxygen storage capacity in cubic ceria based nanocatalysts for low temperature catalytic combustion of fuels

A series of praseodymium (Pr) doped cubic ceria nanoparticles (CeO₂ NPs) with different ratio of cerium (Ce) and ‘Pr’ was synthesized by hydrothermal method. Manganese (‘Mn’) doped cubic CeO₂ NPs with 10:90 ratio of Mn:Ce and undoped cubic CeO₂ NPs have also been synthesized. The crystalline structure of the synthesized nanomaterials has been studied by powder X-Ray diffraction (XRD) and Rietveld analysis. In the Raman spectrum, the intensity of F_2g signal at 450–460 cm⁻¹ decreased while the intensity of extrinsic vacancy at 570–580 cm⁻¹ increased by doping with ‘Pr’ or ‘Mn’ in cubic CeO₂ nanocrystals. X-ray photoelectron spectroscopy (XPS) results showed that surface oxygen vacancy of cubic CeO₂ NPs increased by doping with 25 % of ‘Pr’. The ‘Pr’ doped CeO₂ NPs (Pr:Ce = 25:75) exhibited higher surface adsorption dynamic oxygen storage capacity (OSC_Dyn), while the ‘Mn’ doped cubic CeO₂ NPs (Mn:Ce = 10:90) showed increased bulk lattice OSC_Dyn. The ‘Pr’ doped cubic CeO₂ NPs (Pr:Ce = 25:75) exhibited better low temperature catalytic combustion activity, and their nanodispersion in mineral turpentine oil (MTO) added liquefied petroleum gas (LPG) exhibited better fuel efficiency with a flame temperature of 912 °C.