Internships Magnetic Resonance Research Center
Overhauser DNP in supercritical CO2 (master)
Contact: Prof.dr. Arno Kentgens
NMR is a powerful technique, but it is limited by its low sensitivity. One way to improve the sensitivity of NMR is by using Dynamic Nuclear Polarization (DNP). In DNP the large magnetization of electron spins is transferred to nuclear spins by microwaves. In our lab we have a gyrotron available to generate microwaves, which can be used with the 600 MHz NMR magnet. We have developed a probe with which DNP experiments can be performed in supercritical CO2. The supercritical CO2 is generated by a Supercritical Fluid Chromatograph (SFC). This system would allow NMR experiments with high sensitivity, which is particularly relevant for the study of complex mixtures. In this project experiments with this novel setup will be developed and performed.
Rapid-melt DNP (master)
Contact: Prof.dr. Arno Kentgens
In our lab we use stripline NMR detectors, with which samples in capillaries can investigated with good sensitivity. An advantage of such a small samples is that due to their low volume, they will change phase (i.e. melt) very rapidly when subjected to a temperature change. We have developed a rapid-melt DNP probe in which a capillary can be moved by a motor between three positions in the probe. In the bottom position the sample is frozen by a flow of liquid nitrogen. While the sample is frozen it is irradiated with microwaves, which will increase the polarization of the nuclear spins by a DNP effect. The sample is then moved to the middle position, which is heated. Since the sample is melted rapidly, the enhanced polarization is not lost due to relaxation. Finally the sample is moved to the top position where a stripline detector is used to record the NMR signal where the large polarization results in a high sensitivity. If you are interested in developing new experiments with this system please contact us.
micoMAS of tissue samples (master)
Contact: Prof.dr. Arno Kentgens
In our lab a micro Magic Angle Spinning (microMAS [1]) probe has been developed. With this probe we can can study samples of down to the nanoliter volumes. An interesting application of this technique is to study tissue samples with High Resolution MAS (HRMAS). This could, for example, be applied to microscopic samples obtained from a biopsy. In this project a microMAS for tissue samples will be developed. As this internship is more involved it is suitable for master intenships.
[1] Phys. Chem. Chem. Phys., 2016, 18, 4902-4910
Large-scale energy storage
Contact: Dr. Evan Wenbo Zhao
Large-scale energy storage is becoming increasingly critical to balance the intermittency between renewable energy production and consumption. Redox Flow Batteries (RFBs), based on inexpensive and sustainable redox-active materials, are promising storage technologies. A RFB consists of two tanks of redox-active electrolytes, one catholyte and one anolyte, and its capacity can be scaled up just by increasing the volume of the tanks. The electrolytes flow through an electrochemical cell where redox reactions happen. Due to this design, one of the distinct features of RFBs is the decoupling of their energy storage and power generation, which provides unique opportunities for in situ monitoring.
We have developed in situ NMR metrologies to probe the electrolyte in the flow path or in the battery cell (Nature 2020, 579, 224). A wide range of redox processes can be readily studied. For example, using the bulk magnetization changes (observed via the proton NMR shift of the water resonance) of the anthraquinone resonances, we measured the concentration of paramagnetic species and thus demonstrated a new method to measure the state of charge of the battery (UK patent application 2102339.5).
Internship projects are available on various aspects of the operando NMR studies of flow batteries and electrocatalytic nitrogen/carbon dioxide reduction. For example, the student can be involved in the development of the second-generation operando NMR methods that incorporates the microfluidic NMR technology. The student will develop a skill set in NMR spectroscopy and electrochemistry, both are fundamentally fun and practically useful.
Internship type
B Chemistry B Science M Molecular Chemistry M Physical Chemistry M Physics of Molecules and Materials
Area
materials chemistry, materials science, physical chemistry, chemical physics, NMR, spectroscopy, analytical chemistry, flow chemistry
Topic
NMR, batteries, renewables, green economy, electrochemistry, catalysis
Impact on
Sustainability, environment, green energy, green IT, renewable energy
Techniques
NMR, solid state NMR, EPR, Voltammetry, Microfluidics