Photocatalytically reductive defluorination of perfluorooctanoic acid (PFOA) using Pt/La2Ti2O7 nanoplates: Experimental and DFT assessment

To enable efficient degradation of perfluorooctanoic acid (PFOA), we prepared and investigated a nanosheet photocatalyst (Pt/La2Ti2O7). Doping platinum nanoparticles on La2Ti2O7 varied the band structure and improved the photocatalytic activity due to the enhanced charge separation. Methanol as the electron donor and sacrificial reagent significantly promoted the photocatalytically reductive degradation of PFOA that reduced by 40% within 180 min under UV254 irradiation (1 mW∙cm2). The density functional theory calculations were used to analyze the effects of Pt doping and band structures on interfacial electron transfer and degradation pathways. As opposed to photocatalytic oxidation, this UV/Pt/La2Ti2O7/CH3OH photocatalysis could abstract electrons from methanol and convert to free reactive radicals and photo-generated electrons to reductively defluorinate PFOA and potentially other polyhalogenated or perhalogenated organic compounds.