Development of ternary Pt/BaTiO3/Bi2O3 heterostructured piezo-photocatalysts for antibiotic degradation

Abstract

The efficient separation of surface and bulk photocarriers is very crucial for improving the photocatalytic activity of semiconductors. To achieve this goal, herein we have developed ternary Pt/BaTiO3/Bi2O3 (Pt/BTO/BO) heterostructured piezo-photocatalysts with high capacity for antibiotic degradation. The ternary heterostructures were constructed by anchoring BTO and Pt nanoparticles on the surface of BO microrods. Their piezo-photocatalytic performance and mechanism was elucidated through the degradation of ciprofloxacin (CIP). It is revealed that the ternary heterostructures exhibit obviously enhanced photocatalysis under illumination of simulated sunlight; typically the photocatalytic activity of the 2 %Pt/9%BTO/BO sample is improved by 8.2 and 2.4 times over that of single BTO and BO, respectively. This phenomenon originates from the improved separation of photocarriers by the BTO/BO and Pt/BO interface fields. More interestingly, when simulated-sunlight illumination was accompanied with ultrasonic vibration, the piezo-photocatalysis of 2 %Pt/9%BTO/BO shows a further improvement in the CIP degradation. The coupled piezo-photocatalysis shows a synergistic enhancement factor SF = 2.64. Efficient separation of bulk photocarriers, which is caused by ultrasonic-induced piezoelectric polarization field, is the main reason for the elevated piezo-photocatalysis. Additionally, the decomposition process of CIP and potential toxicity of substances generated during the CIP degradation process were elucidated.