Synthesis of anatase TiO2 with exposed (001) facets grown on N-doped reduced graphene oxide for enhanced hydrogen storage

Homogeneously distributed TiO2 nanoparticles with (001) reactive facets were grown over nitrogen-doped reduced graphene oxide sheets (N-rGO) under solvothermal conditions. Hydrogen storage capacity of the system was significantly improved to 0.91 wt% at room temperature and pressure of 0.8 MPa that is the highest hydrogen storage ever reported for graphene-based nanocomposites at room temperature and low pressures. Importantly, this nanocomposite exhibits ~91% capacity retention through 5 cycles with more than 88% release of the stored hydrogen at ambient conditions. Enhanced hydrogen uptake and capacity retention were attributed to the synergistic effect of i) reactive facets of TiO2, ii)high dispersion of nanoparticles with the average size of 6 nm, and iii) strong interaction between substrate and TiO2 nanoparticles through polarized CeN bonding of N-rGO sheets.