Corn-silk-templated synthesis of TiO2 nanotube arrays with Ag3PO4 nanoparticles for efficient oxidation of organic pollutants and pathogenic bacteria under solar light

A novel highly ordered TiO2 nanotube arrays (TiO2 NTAs) have been successfully prepared via a simple, costeffective and environmentally friendly corn-silk-templated strategy, and Ag3PO4 nanoparticles were deposited onto the TiO2 surface by a facile in-situ growth method. The crystal structure, morphology and optical properties of the as-prepared samples were characterized via a series of characterized techniques. Systematic studies demonstrated that Ag3PO4/TiO2 heterojunction photocatalyst displayed enhanced photocatalytic activity for rhodamine B (RhB) and ciprofloxacin (CIP) degradation compared to pristine TiO2 NTAs and Ag3PO4. In addition, Ag3PO4/TiO2 heterojunction exhibited significantly superior antibacterial activity than single component. By UV-vis diffuse reflectance (DRS) and photoluminescence (PL) spectra, the Ag3PO4/TiO2 heterojunction showed enhanced adsorption of visible light and reduced recombination of photo-generated electrons (e-) and holes (h(+)). The photocurrent and electrochemical impedance spectroscopy (EIS) demonstrated that Ag3PO4/TiO2 heterojunction possessed a faster photocurrent, lower charge migration resistance compared to pristine TiO2 NTAs and Ag3PO4. The possible enhanced photocatalytic degradation and disinfection mechanism were studied by employing the active species trapping and electron spin resonance (ESR) experiments, indicating that h(+) and superoxide radicals (center dot O-2(-)) played significant roles during the photocatalytic process. This work provided an attractive avenue to design highly ordered TiO2 nanotube arrays based composite photocatalysts from corn silks for pathogenic bacteria and organic pollutants wastewater purification and will be useful for design of other highly ordered nanotube arrays photocatalysts.