The new Morin – based three-dimensional carbon nanostructures with metal oxides deposits. From synthesis to electro- and photocatalytic applications

Morin is a natural polyphenolic compound best known for its bioactive properties. Due to its flavonoid structure, Morin may also be considered as a potential precursor of diverse functional materials. Sadly, its poor solubility in water altered its application in this field till now. In this work, by applying simple but effective sol-gel reactions, organic and carbon nanostructures were synthesized and described for the first time. We succeeded in porous materials (BET: 50–600 m2/g) with an original 3D morphology, e.g., hollow hexagonal nanopipes, nanobars, or nanofoams. All received carbons contained metal oxides traces (Co, Zn, Mg, Al), originated from corresponding Lewis acids used as catalysts, and formed after the pyrolysis. The CM-Co samples, having around 7 wt. % of cobalt deposits, were chosen to investigate their suitability for electrochemical conversion of CO2 and photochemical oxidation of benzyl alcohol (BnOH). The CM-Co successfully converted CO2 to CH4 with faradic efficiency (FE) of 12 %, wherein the yield of the reaction was correlated with the applied potential of electrolysis. Furthermore, the CO2 reduction was carried out in ambient conditions. The photochemical oxidation of benzyl alcohol to benzaldehyde yielded 14 % efficiency, while the BnOH oxidation process was realized with a sunlight (UV+VIS) simulator.