The design of a hierarchical photocatalyst inspired by natural forest and its usage on hydrogen generation

A novel photocatalyst was designed from the inspiration of natural forest's high efficient on light harvesting and energy conversion. This novel "forest-like" photocatalyst was successfully synthesized by a facile continuously-conducted three steps methods: electrospinning TiO₂ nanofiber acts as the trunks, hydrothermal growth ZnO nanorods on the surface of TiO₂ nanofiber acts as the branches, while photodeposition of Cu nanoparticles on the surface of TiO₂ nanofiber and ZnO nanorods act as the leaves. This novel photocatalyst demonstrated higher photocatalytic hydrogen generation rate than most of semiconductor catalysts and many newly developed catalysts such as Pt/TiO₂ catalyst and artificial leaves Pt/N-TiO₂ catalyst in a water/methanol sacrificial reagent system under the light irradiation as a result of its enhanced light absorption ability, enlarged specific surface area promoting mass transfer and providing more reaction sites and its potential on anti-recombination of electrons and holes. Meanwhile, it is interesting to note that the photocatalytic hydrogen generation activity has a liner relationship with the hierarchy of materials, which means higher hierarchy materials display higher photocatalytic hydrogen generation activity. It is reasonable to believe that this natural mimic photocatalyst without noble metals will benefit the energy generation and novel materials development.