Highly dispersed bismuth oxide quantum dots/graphite carbon nitride nanosheets heterojunctions for visible light photocatalytic redox degradation of environmental pollutants

A facile strategy involving wet impregnation and manual grinding was employed for synthesizing low loading (0.7 wt%) highly dispersed ultra-small quantum dots (QDs) of Bi2O3 anchored graphite carbon nitride (g-C3N4) nanosheets. Post-treatment of the as-prepared Bi2O3 QDs/g-C3N4 by facial photoinduction allowed remarkably boosted photocatalytic removal towards tetracycline (TC) and hexachromium (Cr (VI)) via either oxidation or reduction reactions, with efficiencies about 2.0 and 7.1 times higher than that of pure g-C3N4, respectively. The TC degradation pathways, toxicity reduction of intermediates and TOC elimination studies revealed significantly improved photocatalytic activity resulting from the abundant free radicals of O2−, OH, and h+ that were produced by enhanced interfacial contact and metallic Bi0 bridged charge carrier transfer between Bi2O3 QDs and g-C3N4 nanosheets. In addition, the novel photocatalyst showed long term structural and photocatalytic stabilities.