Revealing the activity origin of oxygen-doped amorphous carbon material for SO2 catalytic oxidation: A descriptor considering dynamic electron transfer during O2 activation

Carbon-based catalytic oxidation widely exists in contamination control, energy conversion and chemical production, in which amorphous carbon containing heteroatom is commonly used carbocatalyst. Compared with crystalline carbon, small-sized aromatic carbon clusters in amorphous carbon exhibit edge and size effect for catalytic oxidation; however, the activity origin, especially accurate activity descriptor remains to be explored. Herein, using SO2 catalytic oxidation as the probe reaction, a combined computational and experimental investigation was conducted to reveal the activity origin of oxygen-doped amorphous carbon. By density functional theory calculations on various oxygen-doped carbon clusters, a site-specific descriptor considering dynamic electron transfer effect was proposed via combining Fukui function and Mulliken electronegativity, based on which the catalytic activity is found to be determined by both oxygen groups and edges. The configuration with cyclic ether embedded into K-region edge is predicted to own the highest activity with O-2 activation and SO(2 )oxidation barrier as low as 35.4 and 89.3 kJ mol(-1). SO2 catalytic oxidation dynamic experiments using model amorphous carbocatalysts further validate the favorable role of ether group and edges. This work demonstrates quantitative descriptor for O-2 activation and catalytic oxidation on amorphous carbocatalyst, providing guidance for designing high-performance carbocatalyst considering size and edge effect.

Automated summary

This study reveals the activity origin of oxygen-doped amorphous carbon catalysts through a combined computational and experimental approach. A site-specific descriptor considering dynamic electron transfer effect is proposed based on density functional theory calculations, which takes into account the influence of both oxygen groups and edges on catalytic activity. Experimental results confirm the favorable role of ether groups and edges in the catalytic oxidation of SO2. This work provides guidance for designing high-performance carbocatalysts considering size and edge effect.