Hydrogen generation enhanced by nano-forest structures

Abstract

In the ongoing attempts to alleviate current energy constraints, hydrogen gas, H₂, is drawing much attention as an alternative energy storage medium to address the issues of limited energy resources as well as air pollution associated with conventional energy technologies. Here we report H₂ generation by thermochemical water-splitting employing a hierarchical CeO₂ nanostructure which allows for maximizing the reaction surface area and enhanced H₂ generation at relatively low temperatures (800 °C or below). More importantly the nanostructure retains the surface area during H₂ generation. The large surface area of the nanostructure was achieved by growing one-dimensional CeO₂/SnO₂ core–shell nanowires on a three-dimensional porous disk. Namely the three-dimensional core–shell “nanowire-forest” has increased H₂ generation by 45.5% at 800 °C, in comparison to conventional CeO₂ thin-film-coated disks used as a reference. Furthermore the total amount of H₂ generated by the nanowire forest over one thermal cycle is greater than that of the previously reported values. We believe that such hierarchical CeO₂ nanostructures offers a highly effective means for producing H₂ gas as well as for other catalytic reactions.