Adsorption/photocatalytic activity and fundamental natures of BiOCl and BiOClxI1−x prepared in water and ethylene glycol environments, and Ag and Au-doping effects

• Published in: Applied catalysis. B, Environmental Vol. 147; pp. 711 - 725
• Main Authors: Kim, Won Joo, Pradhan, Debabrata, Min, Bong-Ki, Sohn, Youngku
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.04.2014
• Subjects: Adsorption; BiOCl; BiOClxI1−x; Doping; Photocatalytic degradation; Photocatalytic degradation; BiOCl; Adsorption; BiOClxI1−x; Doping
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.10.008

•BiOCl and BiOClxI1−x 3D flower and 2D plate nanostructures were synthesized.•Fundamental natures of BiOCl and BiOClxI1−x were fully examined.•Adsorption and photocatalytic dye degradation performance were tested for MO, RdB and MB.•Ag and Au-doping drastically negated the adsorption and photocatalytic performance.•A dye-sensitized mechanism and the roles of actives species were proposed. BiOCl and BiOClxI1−x were synthesized in two different solvents of ethylene glycol (EG) and water, and their natures were examined by scanning electron microscopy (SEM), electron transmission microscopy (TEM), X-ray diffraction, UV–vis absorption and Raman, Fourier-transform infrared, and photoluminescence spectroscopy. The Ag and Au-doping effects on the fundamental nature and photocatalytic activity of BiOCl and BiOClxI1−x were investigated in detail. SEM revealed that 3D flower-like and 2D plate-like microstructures were formed with EG and water solvents, respectively. The as-synthesized samples were tested for the adsorption and photocatalytic degradation of methyl orange and Rhodamine B, with the flower-like 3D-structure showing superior adsorption performance relative to the stacked 2D plate-like structures. Upon introducing iodine into BiOCl, we observed a dramatic increase in the adsorption ability and Brunauer–Emmett–Teller surface area, with an order of 2D BiOCl<3D BiOCl≪BiOClxI1−x (x=0.8, 0.6 and 0.4). The dye degradation performance was further markedly enhanced under irradiation by visible light. However, a small amount of Ag and Au-doping drastically negated the adsorption and photocatalytic performance. The photocatalytic mechanism was elucidated by an indirect chemical probe method using active species scavengers, and photoluminescence spectroscopy. On the basis of the results obtained, we propose a dye-sensitized photodegradation mechanism, and the active species play roles in the order of OH≪O2−≈h+ under visible light irradiation.