Investigation of plasmonic Cu with controlled diameter over TiO2 photoelectrode for solar-to-hydrogen conversion

Abstract

Plasmonic metal nanoparticles (NPs) have been used to improve the solar-to-hydrogen conversion efficiency. Relative to Au and Ag, Cu is cheaper and more abundant. In the present work, Cu NPs with the controlled diameter were deposited on TiO2 nanotube arrays (TNTAs) by using a pulse electrochemical deposition method. When the deposition was cycled 3600 times, the size of Cu NPs can be tuned to approximately 30 nm with the most uniform distribution, resulting in the remarkable characteristic peak of surface plasmon resonance and higher photocurrent density. The hydrogen production rates remained unchanged during irradiation (AM 1.5, 100 mW/cm2) of 2 h, indicating a good stability of the resultant Cu/TNTAs electrode. The photoelectrochemical performances of as-prepared Cu/TNTAs can also be comparable to those of Ag/TNTAs electrode fabricated by the same method.