Carbon Dots for Super-resolution Imaging of Nanoporous Catalysts

Abstract

Mass transport within the pore structure of a catalyst particle is a crucial factor in its catalytic efficiency. Therefore, studying the pore network of a catalyst is vital for rational catalyst design. One promising method for this is super-resolution fluorescence microscopy, which has the potential to localize fluorescent probes within pore spaces with an accuracy below the diffraction limit. In this work, we show that carbon dots based on citric acid and urea have great potential for pore space mapping with confocal laser scanning microscopy and single particle tracking using super- resolution fluorescence microscopy. Furthermore, it is possible to embed a molecular fluorophore, resorufin, inside the CDs for brighter luminescence than pure CDs and therefore enhanced particle localization/tracking. We synthesized and characterized two carbon dot samples using HRTEM, photoluminescence, UV-vis, infrared, and Raman spectroscopy techniques. With these results, we demonstrate that it is possible to use these carbon dots in super-resolution microscopy studies, paving the way for a future application of carbon dots in pore space exploration.