Yong Xue, Nagaraja Thiba, Krishnamoorthy Rajavel, Guanes Ana, Das Suprem R, Martsinovich Natalia
Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom.
Department of Industrial and Manufacturing Systems Engineering, Kansas State University, Manhattan, Kansas 66506, United States.
ACS Appl Nano Mater. 2023 Dec 18;7(16):18386-18397. doi: 10.1021/acsanm.3c04147. eCollection 2024 Aug 23.
Fundamental understanding of the interactions of nanoscale materials with molecules of interest is essential for the development of electronic devices, such as sensors. In particular, structures and molecular interaction properties of engineered graphenes are still largely unexplored, despite these materials' great potential to be used as molecular sensors. As an example of end user application, the detection of phosphorus in the form of phosphate in a soil environment is important for soil fertility and plant growth. However, due to the lack of an affordable technology, it is currently hard to measure the amount of phosphate directly in the soil; therefore, suitable sensor technologies need to be developed for phosphate sensors. In this work, pristine graphene and several modified graphene materials (oxygenated graphene, graphene with vacancies, and curved graphene) were studied as candidates for phosphate sensor materials using density functional theory (DFT) calculations. Our calculations showed that both pristine graphene and functionalized graphene were able to adsorb phosphate species strongly. In addition, these graphene nanomaterials showed selectivity of adsorption of phosphate with respect to nitrate, with stronger adsorption energies for phosphate. Furthermore, our calculations showed significant changes in electrical conductivities of pristine graphene and functionalized graphenes after phosphate species adsorption, in particular, on graphene with oxygen (hydroxyl and epoxide) functional groups. Experimental measurements of electrical resistivity of graphene before and after adsorption of dihydrogen phosphate showed an increase in resistivity upon adsorption of phosphate, consistent with the theoretical predictions. Our results recommend graphene and functionalized graphene-based nanomaterials as good candidates for the development of phosphate sensors.
对于诸如传感器等电子设备的开发而言，深入了解纳米级材料与目标分子之间的相互作用至关重要。特别是，尽管工程石墨烯作为分子传感器具有巨大潜力，但其结构和分子相互作用特性仍在很大程度上未被探索。作为终端用户应用的一个例子，在土壤环境中检测磷酸盐形式的磷对于土壤肥力和植物生长很重要。然而，由于缺乏经济实惠的技术，目前很难直接测量土壤中磷酸盐的含量；因此，需要开发适用于磷酸盐传感器的合适传感技术。在这项工作中，使用密度泛函理论（DFT）计算研究了原始石墨烯和几种改性石墨烯材料（氧化石墨烯、有空位的石墨烯和弯曲石墨烯）作为磷酸盐传感材料的候选物。我们的计算表明，原始石墨烯和功能化石墨烯都能够强烈吸附磷酸盐物种。此外，这些石墨烯纳米材料对磷酸盐的吸附相对于硝酸盐具有选择性，对磷酸盐的吸附能更强。此外，我们的计算表明，在吸附磷酸盐物种后，原始石墨烯和功能化石墨烯的电导率发生了显著变化，特别是在具有氧（羟基和环氧基）官能团的石墨烯上。磷酸二氢吸附前后石墨烯电阻率的实验测量表明，吸附磷酸盐后电阻率增加，这与理论预测一致。我们的结果推荐石墨烯和功能化石墨烯基纳米材料作为开发磷酸盐传感器的良好候选材料。
