Promoting visible-light-induced photocatalytic degradation of tetracycline by an efficient and stable beta-Bi2O3@g-C3N4 core/shell nanocomposite

The elimination of recalcitrant pollutants from wastewater using core/shell structure photocatalysts has received much attention in the area of environmental science. In this study, novel beta-Bi2O3@g-C3N4 core/shell nanocomposites were firstly fabricated via a feasible self-assembly methodology, in which beta-Bi2O3 nanoparticles were chosen as the host material for g-C3N4 loading. The photocatalytic activity of the samples were evaluated by the degradation of antibiotic tetracycline (TC) under visible-light illumination (lambda > 420 nm). Compared to the pristine beta-Bi2O3 and g-C3N4, the prepared core/shell nanocomposites showed remarkably enhanced photocatalytic performance towards TC degradation in aqueous solution. Eventually, the 5 wt% g-C3N4 loaded core/shell sample (5% CN@BO) exhibited the optimum photocatalytic efficiency, and its rate constant (k = 0.0311 min(-1)) for TC degradation is much higher than lots of the previously reported photocatalysts. In addition, the as-synthesized 5% CN@BO also displayed excellent photostability for degradation of TC even after 5 times recycling tests. The highly visible-light-induced photoreactivity is ascribed to the formation of a core/shell Z-scheme heterojunction, which could significantly accelerate the separation of photoinduced electron-hole pairs and prolong the lifetime of charge carriers. This work provides an efficient core/shell nanomaterial for removal of antibiotic pollutants and will be useful for design of other core/shell photocatalysts.