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 Au 3+ sites at the expense of conversion loss. Under appropriate sulfonation, Au/S 1 CNT 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.

In this work, a series of colloidal gold nanoparticles with controllable sizes and CeO2 promotion were anchored on carbon nanotubes (CNT) for the aerobic oxidation of benzyl alcohol.

Tiny gold nanoparticles were successfully anchored on carbon nanotubes (CNT) with NiO decoration by a two-step synthesis. Characterizations suggested that Ni species in an oxidative state preferred to be highly dispersed on CNT. During the synthesis, in situ reduction by NaBH4 and thermal treatment in oxidation atmosphere were consequently carried out, causing the formation of Au-Ni-Ox interfaces and bimetal hybrid structure depending on the Ni/Au atomic ratios. With an appropriate Ni/Au atomic ratio of 8:1, Ni atoms migrated into the sub-layers of Au particles and induced the lattice contraction of Au particles, whilst a higher Ni/Au atomic ratio led to the accumulation of NiO fractions surrounding Au particles. Both contributed to the well-defined Au-Ni-Ox interface and accelerated reaction rates. Nickel species acted as structure promoters with essential Au-Ni-Ox hybrid structure as well as the active oxygen supplier, accounting for the enhanced activity for benzyl alcohol oxidation. However, the over-layer of unsaturated gold sites easily occured under a high Ni/Au ratio, resulting in a lower reaction rate. With an Au/Ni atomic ratio of 8:1, the specific rate of AuNi8/CNT reached 185 μmol/g/s at only 50 °C in O2 at ordinary pressure.