| As photocatalysts,inorganic semiconductors have shown their unique advantages,among which TiO2 has become a research focus for its strong oxidizing property,well-maintained chemical stability,environment friendly and non-toxic nature and low cost.However,bare TiO2 photocatalyst is facing some bottlenecks in photocatalysis.For example,the wide band gap of 3.2 eV limits the light absorption to an ultraviolet range,which only accounts for 5%full solar spectrum.On the other hand,the lack of highly active reaction sites on surface causes the low efficiency of consuming the photogenerated carriers by reaction species,while the carriers suffer from severe charge recombination.These limitations largely hinder the practical application of TiO2 in photocatalytic hydrogen production.In order to improve the photocatalytic efficiency of TiO2,we decide to load metal nanostructures on the TiO2 semiconductor.The metal and semiconductor can build a Schottky junction as that electrons are more likely to flow from metal to semiconductor,spatially improving charge separation.Meanwhile,we employ metal nanostructures with a plasmonic effect in the design,whose morphologies can be tailored to allow the absorption of visible and near-infrared light.The utilization of visible and near-infrared light has always been the pursuit of photocatalysis research.In our work,an approach is developed to integrate dual plasmonic nanostructures with TiO2 semiconductor nanosheets for photocatalytic hydrogen production in visible and near-infrared spectral regions.Specifically,the usage of Au nanocubes and nanocages in this work can harvest visible and near-infrared light,respectively,and generate and inject hot electrons into TiO2.Moreover,we employ Pd nanocubes as a co-catalyst that can trap the energetic electrons from TiO2 and efficiently participate in the hydrogen evolution reaction toward improved catalytic activity.Enabled by this unique integration design,the hydrogen production rate of Au cube/cage-TiO2-Pd cube is dramatically higher than those of its counterpart structures-Au cube/cage-TiO2,Au cube-TiO2,Au cage-TiO2 and TiO2.This work represents a step toward the rational design of semiconductor-metal hybrid structures for broadband photocatalysis. |
