Minor Impact of Ligand Shell Steric Profile on Colloidal Nanocarbon Catalysis

Abstract

The catalytic activity of a colloidal nanoparticle is typically inhibited by the very capping agents that are required to maintain colloidal stability and catalyst dispersion. However, the relative importance of steric contributions to the observed attenuation in catalytic activity is poorly understood. Herein, we prepare colloidal graphitic carbon nanoparticles featuring covalent amide linkages to aliphatic surface capping agents of varying length. Using aerobic benzylamine oxidation as a test reaction, we find that the steric profile of the ligand shell plays a negligible role in suppressing catalytic activity relative to chemisorption interactions that alter the surface chemistry of the catalyst. The work suggests that heterostructured nanoparticles that provide distinct surface sites for ligand binding and substrate activation should allow for high colloidal stability and robust catalytic activity