Particle size effect of TiO2 on the catalysis of MgH2

MgH 2 is a hydrogen storage material with high hydrogen absorption/release temperatures and poor kinetics. Although a large number of catalysts capable of optimizing the performance of MgH 2 have been developed in recent years, there are relatively few studies focus on its size effect. In this work, TiO 2 particles with the similar morphology but different sizes were synthesized. It shows that reducing particle size within a certain range (from 1.3 μm to 60 nm) can dramatically enhance the catalytic effect of TiO 2 on MgH 2 . However, when the catalyst size reduces from 60 to 25 nm, due to the severe agglomeration of nanoparticles, there is a little improvement in the dehydrogenation temperature, but an obvious improvement in dynamics. It can be seen in solid-state catalytic systems, merely considering particle size while ignoring the problem of agglomeration and dispersion form of the catalyst in the matrix cannot achieve the best catalytic effect. • TiO 2 with different particle size of 25 nm, 60 nm and 1.3 μm was synthesized. • The 25 nm TiO 2 demonstrated the most notable improvement in performance. • Multivalent titanium ions reduced the E a of de-/hydrogenation reaction of MgH 2 .