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COMMON PART

Project Number23-72-01042

Project titleDevelopment of a spectral method for the qualitative and quantitative determination of surface groups of carbon nanoparticles

Project LeadVervald Alexey

AffiliationFederal State Budgetary Educational Institution of Higher Education Lomonosov Moscow State University,

Research area 02 - PHYSICS AND SPACE SCIENCES, 02-204 - Nano- and microstructures

Keywordscarbon nanoparticles, nanodiamonds, carbon dots, IR absorption spectroscopy, surface groups, quantum chemistry

PROJECT CONTENT

Annotation
The purpose of this Project is to develop a method for determining the type of functional groups and their amount on the surface of carbon nanoparticles - nanodiamonds and carbon dots - using IR absorption spectroscopy and quantum chemical calculations. Targeted synthesis of carbon nanoparticles with desired properties is significantly hampered by the complexity of determining the structure and composition of their cores and surfaces. IR absorption spectroscopy in combination with Raman spectroscopy is routinely used for such an analysis, however, the chaotic structure of the surfaces of the synthesized CNPs and their active interaction with solvent molecules prevents an unambiguous interpretation of the obtained spectra. This Project is aimed at complementing the method of analyzing the CNP structure with vibrational spectroscopy methods using numerical simulation and chemical methods. The relevance and scientific significance of the planned research is due to the wide prospects for the use of carbon nanoparticles in various fields of science, technology, and industry. At present, CNP-based additives to liquid media are being actively developed to improve the rheological properties of liquids, nanosensors of environmental parameters, heavy metal ions, and biomacromolecules. ND and CD are widely used in bionanomedicine as luminescent markers, drug carriers, theranostic objects, and also as a basis for bioconjugates. In most of these applications, the most important thing for optimizing the properties of CNPs is knowledge of the structure and composition of their cores and surfaces. Information about the qualitative composition of the surface groups of CNPs responsible for the interaction of CNPs with environmental molecules can be obtained by IR spectroscopy, X-ray spectroscopy, and titration methods. However, due to the high complexity of the CNP spectra and their great diversity, the possibilities of this method are far from being fully used. Until now, there is no method for quantitative determination of the composition of the CNP cover using IR absorption spectroscopy. The main difficulty in interpreting the IR absorption spectra is due to the fact that the position and shape of the vibrational bands of different groups depend significantly on the local environment (structural elements of the CNPs themselves and solvent/environment molecules). In the case of actively developed CNP surfaces, the bands often overlap. This situation leads to a large number of errors in the interpretation of spectra, and to improve the accuracy of interpretation, it is necessary to involve data from other methods: gravimetric analysis, X-ray spectroscopy, and NMR spectroscopy. This approach significantly complicates and increases the cost of ongoing research. In the case of successful implementation of this Project, the dependences of changes in the IR absorption bands of CNPs on changes in their local environment will be determined and a method for their more accurate interpretation based on the results of quantum chemical modeling without involving additional complex experimental methods will be developed. This method will provide rapid information on the structure and composition of the surface groups of CNPs, as well as improve the optimization of the properties of CNPs for their specific applications. The experience and groundwork of the head and executors of the Project in the field of vibrational spectroscopy of carbon nanoparticles and their suspensions, the experience of analyzing the results obtained using quantum chemical modeling (see p. 4.7.), as well as the available equipment, gives confidence in the successful solution of the tasks set in the Project tasks and the possibility of obtaining planned results.

Expected results
Upon completion of the Project, regularities in the formation of IR absorption spectra of CNP surface groups will be studied both from the experimental and theoretical side. The possibility of quantitative interpretation of the CNP IR absorption spectra using various implementations of the internal reference will be investigated. A method will be developed for the refined interpretation of the IR absorption spectra of CNP at a qualitative and quantitative level. The proposed method for qualitative and quantitative determination of the composition of surface functional groups will be express and does not require sample preparation. The successful implementation of this Project will improve our knowledge of the structure of CNP surfaces, and more accurately, quickly and cheaply obtain information about new carbon nanoparticles used in engineering, biomedicine, ecology, and agriculture The scale and complexity of the tasks set are due to the planned research in various fields of science - at the intersection of spectroscopy, materials science, chemistry, and mathematics. Successful implementation of the Project will make a significant contribution to solving the fundamental problems of modern physics of nanostructures and will ensure wide applications of carbon nanoparticles in biomedicine, sensors, electronic industry, etc.

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