Redox behaviour of CaxLa1-xVO4-d

Mixed oxides of generic composition, CaxLa1-xVO4-δ (x = 0.0 - 1.0), were synthesised by solid state reaction route and characterization was carried out using powder XRD and IR techniques. Redox behaviour was evaluated by recording successive temperature programmed reduction (TPR) - oxidation (TPO) cycles. XRD results depict gradual substitution of La3+ by Ca2+, which transforms monoclinic LaVO4 structure to triclinic Ca2V2O7 symmetry. Though addition of calcium did not gave rise to any significant changes in temperature programmed reduction profile, Ca0.2La0.8VO4-δ sample showed better reproducibility for successive redox cycles. Thus one can obtain better stability and lowering of redox process temperatures, which indicate for its suitability as an oxidation catalyst. (author)