Effects of the molar ratio on the photo-generated charge separation behaviors and photocatalytic activities of (BiO)2CO3-BiOBr composites

• The photo-induced charge separation rate has been remarkably enhanced.
• No different electronic transfer property occurs.
• The composite with 3/4 M ratio of (BiO)2CO3/BiOBr has the best activity.

The molar ratio of two semiconductors will remarkably influence the photo-induced charge separation behaviors of the composites constructed, thus affecting the corresponding photocatalytic activity. Therefore, it is critical to reveal the relationship between the molar ratio of two semiconductors and the photo-induced charge separation; the information can shed light on the study of nature of surface catalysis. In this work, (BiO)2CO3-BiOBr composites were facilely fabricated in-situ through a pore impregnating approach using HBr aqueous solution. The samples were studied by BET, XRD, SEM, UV–Vis DRS and surface photovoltage spectroscopy (SPS). The photocatalytic activities of the samples were evaluated by the discoloration of methyl orange (MO) aqueous solution upon the simulated sunlight illumination. The results reveal that the (BiO)2CO3-BiOBr composite with 3/4 M ratio of (BiO)2CO3/BiOBr displays the highest photo-induced charge separation rate and photocatalytic activity, the results further manifest that no different electronic transfer property occurs after coupling (BiO)2CO3 with BiOBr.

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