Au Nanoparticles Anchored on Sulfonated Carbon Nanotubes for Benzyl Alcohol Oxidation

Abstract

Promotion of gold (Au)–support synergy provides considerable opportunities to enhance the thermal stability of nanoscale gold catalysts. In this work, we developed an anchorage strategy for Au on sulfonated carbon nanotubes (CNTs), inspired by the mysterious Au–S synergy. S species existed mainly as sulfonyl groups with a tiny quantity of S atoms inserted in the carbon skeleton. The geometric and electronic structures of gold particles were modified, rendering them efficient for the selective oxidation of benzyl alcohol. Using integrated experimental and theoretical approaches, we explicitly show that Au particles of around 2.6 nm were highly dispersed at a S/C ratio of 1.4 at. %. Electrons were delivered from Au to the support with a maximized Au–C interfacial perimeter and promoted adsorption ability with the reactant. However, high S/C atomic ratios (≥3.9%) resulted in increased surface acidity and self-rearrangement of particles with abundant high-coordinated Au3+ sites at the expense of conversion loss. Under appropriate sulfonation, Au/S1CNT exhibited a TOF value of 2294 h–1 at only 50 °C. This work disentangled the structure manipulation of Au catalyst with a suitable action mode between Au and S species to afford a better Au catalyst with resistance to coarsening.