Preparation of concentrated multilayer graphene dispersions and TiO2-graphene composites for enhanced hydrogen production

摘要

Photocatalytic hydrogen (H-2) production is an attractive hydrogen production technology. It is initiated by charge-separation in titanium (IV) dioxide (TiO2) upon photoexcitation. Electrons reduce water to generate H-2 while holes oxidize hydroxide to generate hydroxyl radicals. TiO2 is widely used because it is inexpensive, chemically stable, nontoxic, and environmentally friendly. The activity of TiO2 is limited, but adding a supporting noble metal nanoparticle such as platinum greatly enhances it. Due to resource risks and cost issues, we consider using graphene as an alternative to noble metal nanoparticles. Herein we report a new method to prepare a concentrated multilayer graphene solution and hydrogen production from an aqueous methanol solution. When we used graphene with different sheet sizes or improved the aggregation of TiO2 (770-9), the H-2 evolution rate is 1.6 times higher than that of pristine TIO-9. The contact state and the dispersed state of graphene and TiO2 play important roles in improving the activity.