Enhanced catalytic effect of TiO2@rGO synthesized by one-pot ethylene glycol-assisted solvothermal method for MgH2

•Much smaller and uniform TiO2 nanoparticles are achieved during solvothermal process with ethylene glycol as solvent.•MgH2-70TiO2@rGO composite starts to release hydrogen at 240 °C.•Encapsulation structure and multivalent titanium compounds lead to the enhanced hydrogen storage properties. Schematic illustration for the preparation of catalysts. [Display omitted] In this paper, we synthesized graphene-supported TiO2 nanoparticles (TiO2@rGO) via solvothermal method with different solvents. The combined effect of ethylene glycol (EG) and graphene makes fine, uniform TiO2 nanoparticles during solvothermal process. The effects of milling time and TiO2 content on hydrogen storage performance of MgH2 were investigated systematically. The MgH2-70TiO2@rGO-EG composite milled for 10 h starts to release hydrogen at 240 °C. The composite can desorb 6.0 wt% hydrogen within 6 min at 300 °C, while it can absorb 5.9 wt% hydrogen within 2 min at 200 °C. XPS and TEM results indicate that Mg encapsulated with catalyst as well as Ti4+ partially reduced to Ti2+ can make more intimate contacts and promote the charge transfer, which are responsible for the good de-/hydrogenation kinetics performance of MgH2.