Pt/POMs/TiO composite nanofibers with an enhanced visible-light photocatalytic performance for environmental remediation.

Herein, a novel series of PMo-TiO composites deposited with Pt nanoparticles (NPs), namely X%Pt/PMo/TiO (PMo = HPMoO; X stands for wt% of Pt to the PMo/TiO sample and X = 3, 5, 8, and 10), were prepared through a simple electrospinning/calcination method, followed by photoreduction. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that Pt NPs with an average size of 10 ± 5 nm are well dispersed on the PMo/TiO nanofibers. Photocatalytic tests revealed that the as-prepared Pt/PMo/TiO composite catalysts exhibited excellent and persistent photocatalytic activity for removing methyl orange, tetracycline, Bisphenol A and Cr(vi) under visible-light illumination (λ > 420 nm). Among the as-prepared composites, the 8%Pt/PMo/TiO sample displayed the best photocatalytic activity with the rate constants of 0.011 min (MO), 0.043 min (TC), 0.00615 min (Bisphenol A) and 0.053 min (Cr(vi)). The addition of POM PMo to the composites enhanced the visible-light adsorption and redox ability of TiO. Furthermore, Pt NPs exhibited localized surface plasmon resonance (LSPR) absorption, therefore improving the absorption of visible light by PMo/TiO. Additionally, intense local electromagnetic fields resulted from LSPR, which greatly facilitated the separation of photo-produced charge carriers in Pt/PMo/TiO. The results of free radical- and hole-trapping tests suggested that ˙OH and ˙O were responsible for the degradation of MO/TC. Finally, the corresponding photocatalytic mechanism was proposed.