In situ fabrication of I-doped Bi2O2CO3/g-C3N4 heterojunctions for enhanced photodegradation activity under visible light.

ABSTRACT

Iodine-doped Bi2O2CO3/g-C3N4 heterojunctions consisting of graphitic carbon nitride (g-C3N4) and iodine-doped bismutite (Bi2O2CO3) components were successfully in situ synthesized by a one-pot hydrothermal method. Characterizations such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) demonstrated iodine was favorably doped into the Bi2O2CO3 component, of which the {001} facets grew in situ from {002} facets of g-C3N4 for the heterostructure construction of I-doped Bi2O2CO3/g-C3N4 (IB/CN). The photocatalytic activity of catalysts was evaluated by the degradation efficiency of 1,5-dihydroxynaphthalene under visible light. 1.5-IB/CN with a reasonable iodine doping amount (Bi I molar ratio = 1.0 1.5) exhibited the superior photodegradation performance compared to Bi2O2CO3, achieving an 85.5% removal ratio after 100 min illumination. The enhanced activity of 1.5-IB/CN was attributed to both of the heterostructure that promoted the separation of photoinduced carriers and iodine doping that tuned the bandgap for sufficient visible-light harvesting. The degradation intermediates of 1,5-dihydroxynaphthalene in the system were determined and its possible photodegradation pathway was proposed in detail. This study provides a rational approach for enhancing the visible-light catalytic activity of wide-bandgap Bi2O2CO3, and reveals a new perspective on the removal mechanism of organic pollutants.