Boosted photoelectrochemical activity of anodic titanium dioxide nanotubes by electrophoretically decorated nickel-aluminum layered double hydroxide

Abstract

The splitting of water using photoelectrochemical (PEC) processes is a promising method for generating renewable hydrogen. However, the practical efficiency of converting solar energy to fuel in PEC systems remains limited by inadequate light absorption and the swift recombination of photogenerated charge carriers within the photoelectrode material. In our research, we present a photoanode that addresses these challenges. In this work, we report on the electrophoretic deposition of nickel-aluminum layered double hydroxide (NiAl-LDH) under different voltages onto anodic TiO2 nanotube arrays (TNTAs) as a convenient and economically viable fabrication route of versatile and durable photoanodes. PEC and optical spectroscopy examinations, including linear sweep voltammetry, electrochemical impedance spectroscopy, Mott-Schottky plots, and diffuse reflectance spectroscopy, reveal that NiAl-LDH/TNTAs composites exhibit a superior enhancement of visible light absorption and consequently water splitting photocurrent. We interpret the improvement of PEC water splitting performance of the NiAl-LDH/TNTAs with the band structure speculated by the binding energy and the flat-band potential and band-gap measurements which features this nanocomposite as a novel photocatalyst for future hydrogen energy applications.