STUDIES ON TiO2 NANOPARTICLES AS CATALYST FOR ENHANCED DESORPTION CHARACTERISTICS OF NaAlH4

TiO 2 (np) has been found to be an effective catalyst over ZrO 2 (np) for improving the hydrogen storage characteristics of NaAlH 4 . TiO 2 catalyst reduces the activation energy of NaAlH 4 to a better extent than ZrO 2 . In the reversibly hydrogenated materials, a substantial reduction in the dehydrogenation temperature could be achieved using TiO 2 catalyst. Such effect was not observed through ZrO 2 . The activation energy of the reversibly hydrogenated NaAlH 4 catalyzed by TiO 2 nanoparticles obtained in the present study (60 kJ/mol H 2 ) is smaller than that of TiO 2 : NaAlH 4 starting material (101.9 kJ/mol H 2 ). The stability of the intermediate phase Na 3 AlH 6 in the presence of TiO 2 catalyst was studied through TPD and TPA analysis. XRD analysis confirms that only TiO 2 gets reduced during dehydrogenation; therefore, the observed effect is attributed to the consequence of reduction of TiO 2 .