Insight into highly efficient simultaneous photocatalytic removal of Cr(VI) and 2,4-diclorophenol under visible light irradiation by phosphorus doped porous ultrathin g-C3N4 nanosheets from aqueous media: Performance and reaction mechanism
Insight into highly efficient simultaneous photocatalytic removal of Cr(VI) and 2,4-diclorophenol under visible light irradiation by phosphorus doped porous ultrathin g-C3N4 nanosheets from aqueous media: Performance and reaction mechanism
复制标题
深入了解磷掺杂多孔超薄 g-C3N4 纳米片在可见光照射下从水介质中高效同时光催化去除 Cr(VI) 和 2,4-二氯苯酚：性能和反应机制
DOI：
10.1016/j.apcatb.2016.10.046
复制
发表时间：
2017-04-01
影响因子：
22.1
通讯作者：
Wang, Jingjing
中科院分区：
文献类型：
--
作者：
Deng, Yaocheng;Tang, Lin;Wang, Jingjing
氮化碳(g-C3N4)因其在析氢和光催化降解中的广泛应用而备受关注。本研究采用元素掺杂和热剥离的方法，成功地制备了磷掺杂超薄氮化碳多孔片(PCN-S)。用X射线衍射仪、扫描电子显微镜、透射电子显微镜、N-2-吸附-脱附法、FT-IR、XPS、UV-Vis漫反射光谱、光致发光(PL)、光电流响应(I-t)和电子能谱(ELS)对制备的PCN-S进行了表征。结果表明，PCN-S具有规则的g-C3N4晶体结构、较大的比表面积和纳米片状结构，表面有大量的面孔，化学稳定性好，对整个可见光区域有较宽的光响应，这归因于磷元素的掺杂。在可见光照射下，不同样品对六价铬的光催化还原表明，磷掺杂和多孔纳米片层结构对PCN-S的性能提高起着重要的作用。这是因为P元素的掺杂可以拓宽可见光响应区，并且多孔纳米片状结构的大比表面积可以为光催化反应提供大量的活性中心。然后对PCN-S同时光催化还原铬(VI)和氧化2，4-二氯苯酚(2，4-DCP)进行了详细的研究。实验结果表明，较低的pH值和足够的溶解氧有利于铬(VI)的还原和2，4-DCP的氧化。提出了详细的光催化机理。本研究所采用的策略可以为设计具有高光催化活性的g-C3N4基材料提供新的思路，并为处理废水中的Cr(Vl)/2，4-DCP或其他混合污染物提供潜在的可能性。(C)2016爱思唯尔B.V.保留所有权利。
Carbon nitride (g-C3N4) has attracted great attention for its wide applications in hydrogen evolution and photocatalytic degradation. In this study, phosphorus doped porous ultrathin carbon nitride nanosheets (PCN-S) were prepared successfully via the element doping and thermal exfoliation method. The prepared PCN-S was characterized by XRD, SEM, TEM, N-2-adsorption -desorption measurement, FT-IR, XPS, UV-vis diffuse reflectance spectra, photoluminescence (PL), photocurrent response (I-t) and ElS. The results show that PCN-S owns regular crystal structure of g-C3N4, large specific surface areas and nanosheet structure with lots of in-plane pores on its surface, excellent chemical stability, and broad light response to the whole visible light region, which was attributed to the doping of phosphorus element. Under visible light irradiation, the photocatalytic reduction of Cr(VI) over different samples indicated that the P doping and porous nanosheet structure play an important role for the enhanced performance of PCN-S. The reason was that P element doping can broaden the visible light response region, and large specific surface areas from the porous nanosheet structure can provide quantities of active sites for the photocatalytic reaction. Then the detailed study on the PCN-S for simultaneous photocatalytic reduction of Cr(VI) and oxidation of 2,4-diclorophenol (2,4-DCP) was conducted. The experiments results show that low pH value and enough dissolved oxygen were found to promote Cr(VI) reduction and 2,4-DCP oxidation. The detailed photocatalytic mechanism was proposed. The strategies used in this study could provide new insight into the design of g-C3N4 based materials with high photocatalytic activity, and present potential for the treatment of Cr(Vl)/2,4-DCP or other mixed pollutants in wastewater. (C) 2016 Elsevier B.V. All rights reserved.