Correlation between catalytic activity and surface ligands of monolayer protected gold nanoparticles

► Different ligand-capped Au NPs' thin films and Au NPs' suspensions are synthesized. ► Capping-ligand effect on the catalytic activities of Au NPs' thin films are studied. ► Capping-ligand effect on the catalytic activities of Au NPs' suspension are studied. ► Reduction of nitrophenol and ferricyanide-thiosulfate redox reaction are studied. ► Some ligands completely destroy the catalytic activity of Au NPs.