Ir promotion of TiO2 supported Au catalysts for selective hydrogenation of cinnamaldehyde

•Surface Au-Ir alloy were first synthesized on TiO2 supported catalysts•Surface Au-Ir alloy improved H2 activation capacity and consequent enhanced catalytic activity•Electron transfer from Ir to Au resulted in higher selectivity in cinnamaldehyde hydrogenation.

We synthesized Ir-on-Au (Au–Ir) nanoparticles (NPs) using 8–9 nm Au NPs, which had a partial coverage of Ir. Both the studied systems allowed the obtainment of cinnamyl alcohol with high selectivities (> 83%). However, Au–Ir/TiO2 delivered a hydrogenation rate 5 times higher than that of Au/TiO2. The deposition of Ir onto the surface of Au and the presence of surface Au–Ir alloy were confirmed by UV–vis and HRTEM respectively. Moreover. Moreover, the strongly shifted XPS binding energy implyed the electron transfer from Ir to Au, which was believed to be responsible for the enhanced H2 activation capacity of Au.

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