Solar Hydrogen Generation by Nanoscale p-n Junction of p-type Molybdenum Disulfide-type Nitrogen-Doped Reduced Graphene Oxide

摘要

Molybdenum disulfide (MoS_2) is a promising candidate for solar hydrogen generation but it alone has negligible photocatalytic activity. In this work, 5-20 nm sized p-type MoS_2 nanoplatelets are deposited on the n-type nitrogen-doped reduced graphene oxide (n-rGO) nanosheets to form multiple nanoscale p-n junctions in each rGO nanosheet. The p-MoS_2-rGO heterostructure shows significant photocatalytic activity toward the hydrogen evolution reaction (HER) in the wavelength range from the ultraviolet light through the near-infrared light. The photoelectrochemical measurement shows that the p-MoS_2-rGO junction greatly enhances the charge generation and suppresses the charge recombination, which is responsible for enhancement of solar hydrogen generation. The p-MoS_2-rGO is an earth-abundant and environmentally benign photocatalyst for solar hydrogen generation.