화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.59, No.32, 14224-14233, 2020
Core-Shell TiO2@Au-25/TiO2 Nanowire Arrays Photoanode for Efficient Photoelectrochemical Full Water Splitting
The study of gold (Au) nanoclusters (NCs) as effective co-catalysts has attracted considerable research interests in photoelectrocatalysis. However, it is still a challenge to design an Au NC-hybridized photoelectrode, which exhibits both high performance, particularly in photoelectrocatalytic full water splitting, and long-term photostability. Herein, we present a simple and efficient synthesis strategy for boosting the photoelectrochemical performance and photostability of TiO2 nanowire arrays (NWAs) by loading L-cysteine-capped Au-25 NCs (Au-25(Cys)(18)) followed by coating a TiO2 thin layer via atomic layer deposition (ALD). We revealed that a ligand detaching process had occurred, i.e., the cysteine ligands on Au-25 NCs was in situ etched and Au25 NCs were covered by the protective TiO2 shell in the ALD process, which effectively restricted the loss and size growth of the NCs on the TiO2 surface. Consequently, the designed core-shell structural TiO2@Au-25/TiO2 showed a photocurrent density of 1.35 mA/cm(2) at 1.23 V versus RHE, almost 330% of that for the pristine TiO2 NWAs. Besides, it could produce H-2 and O-2 at a stoichiometric ratio with a favorable rate for PEC full water splitting under simulated solar light irradiation. The nanostructure and the photostability of the composite photoelectrode were well-retained during a long-term recycling test for generation of gases. The rationally designed core-shell structural photoanode provides a facile method for preparation of Au NC-based composite photocatalysts, which is facing the efficient photoelectrochemical water splitting for hydrogen energy production and other potential applications in solar energy conversion.