Ag NPS/g-C3N4纳米复合材料制备及其SERS纳米传感器

通过化学氧化块状石墨型氮化碳(g-C3N4),获得在水中分散性好的片状g-C3N4.XRD,FTIR和XPS表明,所得片状g-C3N4含有氧官能团.这不仅可以作为锚定点负载纳米银粒子(Ag NPs),而且可以获得Ag NPs均匀分散的Ag NPS/g-C3N4纳米复合物.制备的复合材料中银纳米颗粒的重量百分比也会随着硝酸银与片状g-C3N4的质量变化而发生变化.基于g-C3N4对Co2+的明显的拉曼强度响应,Ag NPS/g-C3N4纳米复合物作为表面增强拉曼散射(SERS)传感器检测Co2+.通过拉曼强度的对照,发现随着Co2+浓度的增加,拉曼信号增加;而含有73％银纳米颗粒的Ag NPS/g-C3N4纳米复合物有高的灵敏性,检测极限浓度达到10-9 mol·L-1;复合材料同时显示出高的选择性,对其他如Cd2+,Cu2+和Zn2+的金属离子没有明显的拉曼增强信号.分析了复合材料对Co2+的增强机制.由于Co2+与g-C3N4中的=N-/-NH-基团的耦合,引发复合材料中Ag NPs聚集,从而产生局部电磁场,进而产生表面增强效应.可以预知,Ag NPS/g-C3N4纳米复合物将作为一种用于制造SERS传感器的新的理想材料.

Ag NPS/g-C3N4 Nanosheets Nanocomposites Used for SERS Nanosensors

The graphite-like carbon nitride (g-C3N4) nanosheets with oxygen-containing functional groups,characterized by with XRD,FTIR and XPS,were obtained by applying chemical oxidation of bulk g-C3N4.The oxygen-containing functional groups not only can be used as anchoring sites for silver nanoparticles (Ag NPs),but also help the formation of high scatter for Ag NPs in Ag NPS/g-C3N4 nanosheets nanocompposites.The weight percentage of Ag NPS in the prepared nanocomposites can be controlled by adding silver nitrate.The Ag NPS/g-C3N4 nanosheets nanocompposites are developed as a superior sensor for the detection of Co2+ ions,which are based upon Raman intensity response of g-C3N4 nanosheets to Co2+ ions.With comparison,it was found that Raman signal increase as the increasing of the concentration in Co2+.Results from the weight percentage sensitivity investigations show that Ag NPS content of 73％ in nanocomposites have very low limits of detection (10-9 mol · L-1 for Co2+) in contrast with other Ag NPS content.The sensors also exhibit greater selectivity for Co2+ ions than the other metal ions (Cd2+,Cu2+ and Zn2+).The mechanism is proposed.The localized electromagnetic field is produced around the aggregated Ag NPs with the complexation between Co2+ and =N-/-NH-groups in g-C3N4 occurs,so the increase of SERS signal in the intensity can be observed.It is anticipated that Ag NPS/g-C3N4 nanosheets nanocomposites can be a new class of promising material for fabricating SERS sensors.