Jian Ma,Congjie Liang,Changjiang Yu,Huaming Li,Hui Xu,Yingjie Hua,Chongtai Wang
Photocatalytic reduction of hexavalent chromium (Cr(VI)) is an effective way to reduce its environmental risk. However, it remains a challenge to achieve a high removal rate in mild conditions. In order to efficiently remove Cr(VI) from water, a novel Z-scheme heterojunction composite photocatalyst rCB-20 (Cu 2 O/rGO/BiOBr, 20% Cu 2 O) was successfully prepared using a simple two-step strategy in this work. The characterizations of the catalyst show that the Z-scheme heterojunction formed between Cu 2 O and BiOBr is favorable for facilitating the separation of photogenerated carriers. The existence of rGO can reduce the resistance of electron transport. Therefore, the composite photocatalyst exhibits a very high photocatalytic activity in the photoreduction of Cr(VI). For example, using it to completely remove Cr(VI) with a concentration of 20 mg•L −1 in the pH = 4 solution only requires 40 min. Even the complete removal of the same concentration of Cr(VI) in neutral water at pH 7 does not take more than 90 min. Meanwhile, it possesses a high stability in catalytic activity and structure.
Chong Xu,Fan Yang,Bijian Deng,Sai Che,Wang Yang,Ge Zhang,Yankun Sun,Yongfeng Li
A novel photocatalyst of rGO-wrapped Ti 3 C 2 /TiO 2 nanowires ((Ti 3 C 2 /TiO 2 )@rGO) was successfully synthesized to remove hexavalent chromium (Cr(VI)) and Rhodamine B (RhB) from wastewater. Among the prepared photocatalysts, (Ti 3 C 2 /TiO 2 )@rGO-15 showed the highest photocatalytic activity in both single and mixed pollutant solutions. The excellent photocatalytic activity was ascribed to the enhanced separation efficiency of e - and h + resulted from the Schottky barrier established in (Ti 3 C 2 /TiO 2 )@rGO. Ti 3 C 2 gathered the stimulated electrons originated from TiO 2 and further transferred them to rGO , thus enhancing the separation efficiency of e - and h + . Furthermore, different scavengers were employed to determine the reactive species involved in the photocatalytic reaction system. This work may provide a promising way to promote the separation efficiency of e - and h + via appropriate incorporation of co-catalyst.
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