Cobalt-Nickel Layered Double Hydroxides Modified on TiO2 Nanotube Arrays for Highly Efficient and Stable PEC Water Splitting.

TiO2 -based photoanodes have attracted extensive attention worldwide for photoelectrochemical (PEC) water splitting, but these materials still suffer from poor electron-hole separation and low photoconversion efficiency. Here, the high PEC water splitting activity and long-term stability against photocorrosion of well-aligned hierarchical TiO2 @CoNi-layered double hydroxides nanotube arrays (TiO2 @CoNi-LDHs NTAs) are reported. The typical TiO2 @CoNi-LDHs NTAs exhibits enhancing photocurrent density of 4.4 mA cm-2 at a potential of 1.23 V (vs reversible hydrogen electrode) under AM 1.5G simulated sunlight (100 mW cm-2 ), 3.3 times higher than that of the pristine TiO2 sample. Moreover, this hierarchical electrode displays excellent stability against photocorrosion with initial activity loss no more than 1.0% even after 10 h irradiation in Na2 SO4 electrolyte solution (pH 6.8), much competitive to those reported TiO2 -based photoelectrodes. This work may offer a combinatorial synthesis strategy for the preparation of hierarchical architectures with high PEC performances.