Synergistic Effect of Au–Cu Alloy Nanoparticles on TiO₂ for Efficient Aerobic Catalytic Oxidative Desulfurization

Noble-metal nanoparticles (NPs) have been regarded to be highly active species for the activation of oxygen for numerous catalytic processes but are seriously restricted by their high costs, limited coordination-unsaturated sites for catalysis, etc. In this work, Au-Cu alloy NPs were engineered with TiO2 as the support (AuCu/TiO2). The formation of alloyed structure not only is beneficial to the reduction of noble metal consumption amount but also can promote catalytic performance. Detailed characterizations confirmed that the boosted catalytic activity originates from the synergistic effect between Au and Cu, that is, the electronic structure of Au can be tuned by alloying with Cu, which is in favor of adsorption and activation of oxygen during the catalysis process. The AuCu/TiO2 catalyst induces 98.1% of sulfur removal in catalytic oxidative desulfurization of liquid fuels with oxygen as the oxidant, much higher than that with Au/TiO2 as the catalyst. Moreover, even with the existence of interferents such as aromatic hydrocarbons or olefins, the desulfurization activity shows no obvious decrease. Especially, sulfone is found to be the only product of the desulfurization process with oxygen as the oxidant.