TiO2 nanotube arrays decorated with Au and Bi2S3 nanoparticles for efficient Fe3+ ions detection and dye photocatalytic degradation

Due to increasingly serious environmental problems, many researchers are investigating green clean-energy to solve the world's energy supply issues. So the strategy that Au nanoparticles (Au NPs) and bismuth sulfide (Bi2S3) NPs are used to evenly decorate TiO2 nanotube arrays (TiO2 NTAs) was carried out. Composite materials demonstrated enhanced solar light absorption ability and excellent photoelectrochemical performance. This was attributed to the presence of Bi2S3 NPs with a narrow band gap and the decoration with noble metallic Au NPs which resulted in local surface plasmon resonance (LSPR) effects. The Au/Bi2S3@TiO2 NTAs composites exhibit improved photocatalytic activity for the degradation of methylene blue (MB) under irradiation of UV and visible light. Moreover, the Au/Bi2S3@TiO2 NTAs exhibits high fluorescence emission at 822 nm. Due to the better binding affinity between Bi2S3, TiO2 and Fe3+ ions, the synthesized nanocomposites exhibit high selectivity to Fe3+ ions. The number of binding sites for Au/Bi2S3@TiO2 NTAs was estimated to be 1.41 according to the double logarithmic regression method. The calculated value of “K” was 1862 M−1. Fluorescence emission intensity decreases with increasing concentration (30 μM–5000 μM). The detection limit of the synthesized sensor is 0.221 μM.