基于石墨烯基底的光催化特性

Photocatalytic Properties Based on Graphene Substrate

金属纳米结构中传导电子的集体振荡所产生的表面等离子体不仅可以使电磁场在时间和空间上重新分布,还可以使被激发的载流子重新分布。采用机械剥离法制备了石墨烯材料,借助拉曼光谱扫描技术(Mapping)研究了石墨的层数在二维区域内的分布情况。研究了2-萘硫醇(2-NT)作为探针分子在石墨烯衬底上的SERS增强特性。结果表明2-NT分子的拉曼信号在石墨烯表面得到增强,且石墨烯的SERS增强效果随着层数的越少而增强。基于石墨烯催化基底,借助表面增强拉曼光谱(SERS)技术具有指纹谱的优势,实时监测以对硝基苯硫酚(4NBT)作为探针分子在局域表面等离子体的驱动下发生光催化反应生成4,4’-二巯基偶氮苯(DMAB)。随后,原位引入硼氢化钠在相同的实验条件下,可以将生成物DMAB在等离子体的驱动下再一次发生逆向化学反应生成对氨基硫酚分子(PATP)。在石墨烯催化基底表面上组装一层分布均匀的探针分子4NBT,用一束一定波长的聚焦激光进行照射使其发生光催化反应生成新的分子DMAB。通过这种手段就可以在微纳尺度上绘制出特定有DMAB分子分布的图形或者字母、汉字信息,实现微纳尺度的图形绘制和信息加密。随后,可以借助Mapping,以DMAB分子的特征峰强度进行二维成像就可以实现所绘制图形的显现和信息解密。此外,可以在加密基底上引入硼氢化钠同时在表面等离子体和激发光的作用下发生逆向光催化反应,从而实现微纳尺度图形和加密信息的擦除。

The surface plasma produced by the collective oscillation of conducting electrons in metal nanostructures can redistribute the electromagnetic field in time and space and redistribute the excited carriers.Graphene materials were prepared by the mechanical stripping method.The distribution of the layers in the two-dimensional region was studied by Raman spectroscopy.SERS enhancement of 2-naphthalene mercaptan(2-NT) as probe molecule on graphene substrate was studied.The results show that the Raman signal of the 2-NT molecule is enhanced on the graphene surface,and the SERS enhancement effect of graphene increases with the decrease of the number of layers.Based on graphene catalytic substrate,with the aid of SERS technology,the fingerprint is common.The photocatalytic reaction of 4,4’-dimercaptoazobenzene(DMAB) is generated by the real-time monitoring of p-Nitrobenzene thiophenol(4 NBT) as a probe molecule driven by local surface plasma.Then,under the same experimental conditions,the DMAB can be produced by reverse chemical reaction under the plasma drive to generate para aminothiophenol(PATP) in situ.A uniform probe molecule 4 NBT was assembled on the surface of a graphene catalytic substrate.The light Cui reaction was carried out by a certain wavelength focused laser to generate a new molecule DMAB.By this means,the specific DMAB molecular distribution or letters and Chinese characters information can be drawn on the micro nano-scale,and the micro nano-scale graphics drawing,and information encryption can be realized.Then,the graphics can be displayed and decrypted by mapping and two-dimensional imaging with the characteristic peak intensity of DMAB.In addition,the reverse photocatalytic reaction can be carried out by adding sodium borohydride on the encrypted substrate under the action of surface plasma and stimulated light to erase the micro nano scale graph and encrypted information.