Tuning Oxygen Functionalities in Carbon for Enhanced Microwave-Assisted Catalysis

• Ryan Lange, Chemical Engineering, University of Delaware

• Dion Vlachos, DEI, University of Delaware

Microwaves (MWs), one of the alternative ways of electrification, can reduce energy consumption and enhance catalytic performance by selectively heating catalysts. Carbon’s ability to efficiently absorb electromagnetic energy, combined with its easily modifiable surface chemistry, makes it promising for MW-assisted catalysis. Recent studies have shown that introducing oxygen-containing functional groups (OCFGs) can enhance catalytic activity. In this work, multiple oxygen-introduced carbons were prepared with differing nitric acid treatment times and annealing temperatures to explore the relationship between structural changes and dielectric properties. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to assess the structure, microenvironment, and concentrations of OCFGs. Preliminary results suggest that increasing annealing temperature led to a higher ID/IG ratio (Raman), decreased C=O bonding (XPS), and increased loss tangent, likely due to the reduction of amorphous carbon. MW heating performance peaked in the 200–400 °C annealing range, but declined at higher temperatures, suggesting a tradeoff between structural order and functionalization. Nitric acid treatment showed a less linear trend: optimal performance was observed at 6 h, where sp² bonding and C=O content peaked, but declined at longer durations. This could possibly be due to overoxidation or destruction of small graphitic domains. This methodology demonstrates the potential of carbon materials as catalysts for future use in MW-assisted catalytic processes.