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通过化学氧化块状石墨型氮化碳(g-C_3N_4),获得在水中分散性好的片状g-C_3N_4。XRD,FTIR和XPS表明,所得片状g-C_3N_4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-C_3N_4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-C_3N_4的质量变化而发生变化。基于g-C_3N_4对Co~(2+)的明显的拉曼强度响应,Ag NPS/gC3N4纳米复合物作为表面增强拉曼散射(SERS)传感器检测Co~(2+)。通过拉曼强度的对照,发现随着Co~(2+)浓度的增加,拉曼信号增加;而含有73%银纳米颗粒的Ag NPS/g-C_3N_4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Cd~(2+),Cu~(2+)和Zn~(2+)的金属离子没有明显的拉曼增强信号。分析了复合材料对Co~(2+)的增强机制。由于Co~(2+)与g-C_3N_4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-C_3N_4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。
By chemical oxidation of massive graphite carbon nitride (g-C_3N_4), good dispersibility in the water sheet g-C_3N_4. XRD, FTIR and XPS indicated that the resulting flaky g-C_3N_4 contained oxygen functional groups. This not only can be used as an anchor point to load Ag NPs, but also Ag NPS / g-C_3N_4 nanocomposites with uniform dispersion of Ag NPs can be obtained. The weight percentage of silver nanoparticles in the prepared composite also varies with the mass of silver nitrate and flake g-C_3N_4. Based on the apparent Raman intensity response of g-C_3N_4 to Co 2+, Ag NPS / gC3N4 nanocomposites were used as surface-enhanced Raman scattering (SERS) sensors to detect Co 2+. Raman signal increased with the increase of Co 2+ concentration by comparison of Raman intensity, while Ag NPS / g-C 3 N 4 nanocomposite containing 73% silver nanoparticles showed high sensitivity and detection limit The results showed that the composites showed high selectivity at the same concentration of 10 ~ (-9) mol·L -1. The composites showed good selectivity for other Cd 2+, Cu 2+ and Zn 2+, The metal ions did not show any significant Raman enhancement signal. The mechanism of the enhancement of Co ~ (2+) by the composites was analyzed. Due to the coupling between Co 2+ and N - / - NH- groups in g-C 3 N 4, the Ag NPs in the composites are aggregated and a local electromagnetic field is generated, resulting in the surface enhancement effect. It is predicted that the Ag NPS / g-C_3N_4 nanocomposite will be a new ideal material for the fabrication of SERS sensors.