Achieving superior hydrogen sorption kinetics of MgH2 by addition of Ni-doped TiO2 catalysts

MgH ₂ is a high-density hydrogen storage material but requires an efficient catalyst to improve its poor kinetics and reduce high operating temperature. TiO ₂ is a widely used photocatalyst for water splitting and hydrogen production, and has also demonstrated catalytic ability in the gas-solid reaction of MgH ₂. In this study, we synthesize the Ni-doped TiO ₂ nanoparticles, which significantly reduce the hydrogen absorption temperature down to subzero temperatures. The milled composite of MgH ₂ with 10 wt% Ti(5Ni)O ₂ can absorb 5.25 wt% H ₂ within 30 s at 25 °C, 4.30 wt% H ₂ within 50 s at 0 °C, and 3.94 wt% H ₂ within 50 s even at a low temperature of −30 °C. This composite can release 6.04 wt% of hydrogen in 3 min at 250 °C, and the dehydrogenation activation energy is reduced to 74.57±1.36 kJ/mol, a notable reduction in comparison to that observed in pure MgH ₂. This study demonstrates the potential of the modified TiO ₂ as an important kind of catalyst for solid-state hydrogen storage materials.