Synergistic Effects of Plasmonic Gold and Perovskite-Type SrTiO₃ for Enhanced Photocatalytic Performance of TiO₂ Nanotube Arrays

Abstract

Hydrogenated SrTiO3/TiO2 (H:(STO/TiO2)) with unique heterostructured arrays was prepared, followed by the immobilization of plasmonic Au nanoparticles to form robust composite photoelectrodes. The synergistic effects of heterocoupling of perovskite-type STO on TiO2 nanotube arrays and plasmonic Au-decoration substantially improved the photocatalytic performance with visible light. In contrast to pure TiO2, H:(STO/TiO2) facilitated an efficient transfer of electrons between STO and TiO2, and decreased the recombination ratios of photoexcited electron–hole pairs. Plasmonic Au also effectively boosted the photoresponse under irradiation with visible light. Photocurrent density of 2.3 mA cm–2 under visible light irradiation (λ > 400 nm) with IPCE peaking at 17% and a concomitant apparent quantum efficiency of 3.5% in the 580–680 nm region was achieved. Faradaic efficiency was estimated to be about 80% at the oxygen evolution rate of 18.5 μmol cm–2 h–1 under simulated sunlight irradiation (AM1.5G, 100 mW cm–2). With the aid of X-ray absorption spectra in situ and ultrafast transient absorption spectra, the detailed understanding of the underlying mechanism during photoinduced processes in Au/H:(STO/TiO2) is well elucidated.