Advanced quasi-2D amorphous TiOx-Au photocatalyst: Harnessing defects and carriers transport to boost visible-light organic pollutants degradation

Abstract

Amorphous materials have recently garnered significant interest due to their low-cost fabrication methods, extensive surface area and plentiful surface defects, which offer numerous active sites for catalytic reactions. However, carriers self-trapping and recombination caused by bulk defects limit the employment of amorphous materials as photocatalysts. As such, it is essential to adjust the structure and defects to improve carriers utilization for creating high-performance amorphous photocatalysts. In this study, we developed a novel and facile strategy to fabricate a quasi-2D amorphous crepe-like TiOx-Au (cTiOx-Au) photocatalyst, in which the cTiOx was synthesized simply through one-step hydrolysis method at room temperature by constructing discrete reaction system with mass-confinement of the precursor to guide the morphology of the cTiOx. The removal efficiencies of the cTiOx-Au to antibiotic tetracycline (TC) and gaseous pollutant formaldehyde (HCHO) under visible light were 84.43 % and 95.92 %, respectively, which greatly surpassed those of its counterparts, normal amorphous TiOx (amTiOx)-Au (54.32 % and 73.67 %) and crystalline catalyst TiO2-P25-Au (49.29 % and 54.03 %). The remarkable visible-light photocatalytic capacity of cTiOx-Au can be attributed to the unique quasi-2D morphology of cTiOx. The ultrathin nanostructure not only maximizes surface defects and minimizes bulk defects, but also effectively shortens the carriers transport time and reduces recombination probability, on the other hand, it provides ample adsorption sites and accessible binding sites for plasmonic Au nanoparticles to amplify the effect of surface plasmon resonance enhancement. The excellent photocatalytic performances of cTiOx-Au for removing both aqueous and atmospheric pollutants endow it great potential in real environmental remediation applications.