Enhanced selective adsorption and photocatalytic of Ag/Bi2O3 heterostructures modified up-conversion nanoparticles

Abstract

The degradation of organic pollutant by photocatalytic technology is an emerging and effective approach to purify water resources. Herein, we reported a heterostructure with selective adsorption and photocatalysis for the efficient removal of organic pollutant. The photocatalyst was comprised of up-converting nanoparticle (UCNP) coated with Ag/Bi2O3. The specific crystallinity of Bi2O3 facilitated the selective adsorption of organic molecules with negative polarity, Ag nanoparticles loaded on Bi2O3 promoted the visible light absorption, and the up-conversion property of UCNP turned near-infrared light into ultraviolet and visible light improving further light-harvesting efficiency in the whole solar spectrum. The adsorption process for organic pollutants over Ag/UCNP@Bi2O3 obeyed the pseudo-second-order and the Langmuir isotherm models, and the maximum Langmuir adsorption capacity for tetracycline reached to 717.4 mg/g at pH 7. Meanwhile, the photocatalytic degradation rate of Ag/UCNP@Bi2O3 for tetracycline (100 mg/L) achieved to 0.0037 min−1 under Xenon lamp irradiation after the adsorption equilibrium. This study provided a feasible strategy to develop photocatalysts with efficient adsorption and photocatalytic ability for organic pollutant from water.