Enhancing hot electron generation and injection with plasmonic nanostructures

Constructing plasmonic-semiconductor nanoarchitecture provides a photocatalytic platform for enhancing solar energy conversion. The excitation and extraction of energetic carriers are critical for improving energy efficiency, which can be affected by the geometric features of plasmonic structures. An extensive study on morphology dependent hot electron utilization is desirable but challenging. In this paper, we applied photocurrent response from the microscale reaction region on Au-TiO2 photoanode to evaluate the influence of plasmonic morphology in water splitting. We compared the photocurrent of two structures, gold nanospheres and nanorods, under visible illumination. We experimentally proved that the nanorods demonstrate better energy performance. The possible origins of this enhancement are ascribed to the sharp curvature at tips, where strong hot spots boost the generation and injection efficiency of hot electrons. These results may pave a way for a rational geometry design for plasmonic enhanced photocatalysis.