Developing an in situ EXAFS experiment of microwave-induced gelation

Internal gelation is an advanced route to produce small spheres of metal from a nitrate solution. In this work, microwave heating is used to trigger the gelation of the solution. X-ray absorption spectroscopy is a powerful tool to follow the gelation advancement and verify the completeness of a reaction, but in order to use it on falling nitrate droplets, the study is split into two experiments. First, a fluorescence measurement has been carried out on a trickle of small falling cerium nitrate droplets generated at high frequency to verify that capturing a discontinuous signal would not generate too much noise. Then, a measurement of silver nitrate undergoing gelation in a microwave cavity has been performed in transmission mode, which proved that a fast recording method is suitable for following the evolution of chemicals during such a reaction. The combination of both analyses confirms that it is possible to study microwave gelation of falling droplets using X-ray absorption spectroscopy at the SuperXAS beamline.