The shape apart from the size of ceria nanoparticles also has been a major factor in its performance. A preferential growth along the {1 From the investigations done till now, a preferential crystallographic orientation in the {111} plane can be observed from the XRD studies with no other preferential directions like {100} or {110}. More interestingly, as H2O tends to get adsorbed on the preferential plane, the sharp band at 2300 cm -1 (Fig ) corresponds to an H2O adsorption energy of 27.6 kJ/mol which is even less than the reported value. So wan can infer that a nanorod shape of nanoparticles of ceria has grown. However, we have also evidenced the fact that the nanoparticles have undergone heterogeneous agglomeration which has led to a transformation of shape from nanorods to the truncated octahedron. A control on the shape of ceria nanoparticles and ways to avoid agglomeration is beneficial for its practical applications 4. CONCLUSIONS Ceria (CeO2) nanoparticles were synthesized and doped into ZnO. A preferential growth along the highest packing got initiated whose impact on the physical properties was however negated by heterogeneous agglomeration. Evidence of the formation of nanoparticles and defects like oxygen vacancies and excitons was obtained which caused a reduction in the band gap useful for photocatalysis and room-temperature ferromagnetism. UV region was found to be dominant in showing photocatalytic properties, however, a hint of a shift towards the visible region was found which needs further work,