Ag nanoparticles decorated ZnO nanopagodas for Photoelectrochemical application
Marwa Mohamed Abouelela, Go Kawamura, Wai Kian Tan, Muhd Amiruldin, Keiichiro Maegawa, Jin Nishida, Atsunori Matsuda
Abstract
Photoelectrochemical water splitting (PEC-WS) utilizing solar energy and photoelectrodes immersed in an electrolyte has sparked an increased interest in hydrogen production. The PEC-WS efficiency is enhanced by controlling the nanostructure of photoelectrodes and sensitizing them with plasmonic metals. This study shows how the transformation from ZnO nanorods to ZnO nanopagodas and the deposition of Ag nanoparticles improve the photocurrent and PEC conversion efficiency under sunlight. The deposition of an optimal amount of Ag nanoparticles over ZnO nanopagodas exhibited the highest photocurrent of 2.15 mA cm−2 at 1.23 V vs RHE, while pure ZnO nanorods and nanopagodas achieved 0.90 and 1.43 mA cm−2, respectively. This extraordinary improvement in photocurrent density was thoroughly analyzed using various PEC and optical measurements as well as electromagnetic simulation. As a result, two main reasons for the improvement were derived. Firstly, ZnO nanopagodas can reduce the charge recombination rate due to the reduced structural defects and improve the light-harvesting ability due to their distinct superstructure characteristics. Secondly, the deposition of plasmonic Ag nanoparticles can improve the interfacial charge transfer and increase the ability to capture visible light due to their localized surface plasmon resonance effects.