Department of Physics, Chemistry and Biology, Linköping University, SE-58183, Linköping, Sweden.
Frantsevich Institute for Problems of Materials Science, NASU, 03680, Kyiv-142, Ukraine.
Sci Rep. 2017 Jun 21;7(1):3934. doi: 10.1038/s41598-017-04339-8.
The promise of graphene and its derivatives as next generation sensors for real-time detection of toxic heavy metals (HM) requires a clear understanding of behavior of these metals on the graphene surface and response of the graphene to adsorption events. Our calculations herein were focused on the investigation of the interaction between three HMs, namely Cd, Hg and Pb, with graphene quantum dots (GQDs). We determine binding energies and heights of both neutral and charged HM ions on these GQDs. The results show that the adsorption energy of donor-like physisorbed neutral Pb atoms is larger than that of either Cd or Hg. In contrast to the donor-like behavior of elemental HMs, the chemisorbed charged HM species act as typical acceptors. The energy barriers to migration of the neutral adatoms on GQDs are also estimated. In addition, we show how the substitution of a carbon atom by a HM adatom changes the geometric structure of GQDs and hence their electronic and vibrational properties. UV-visible absorption spectra of HM-adsorbed GQDs vary with the size and shape of the GQD. Based on our results, we suggest a route towards the development of a graphene-based sensing platform for the optical detection of toxic HMs.
石墨烯及其衍生物有望成为下一代用于实时检测有毒重金属 (HM) 的传感器，这需要清楚地了解这些金属在石墨烯表面上的行为以及石墨烯对吸附事件的响应。我们在此处的计算重点是研究三种 HM（即 Cd、Hg 和 Pb）与石墨烯量子点 (GQDs) 之间的相互作用。我们确定了中性和带电 HM 离子在这些 GQDs 上的结合能和高度。结果表明，供体型物理吸附中性 Pb 原子的吸附能大于 Cd 或 Hg。与元素 HM 的供体型行为相反，化学吸附的带电 HM 物种表现为典型的受体。中性吸附原子在 GQDs 上迁移的能垒也被估算出来。此外，我们展示了 HM 吸附原子取代碳原子如何改变 GQDs 的几何结构，从而改变它们的电子和振动特性。HM 吸附的 GQDs 的紫外-可见吸收光谱随 GQD 的尺寸和形状而变化。基于我们的结果，我们提出了一种开发基于石墨烯的传感平台的途径，用于光学检测有毒 HM。
