Atmosphere induced amorphous and permeable carbon layer encapsulating PtGa catalyst for selective cinnamaldehyde hydrogenation

In this work, an alloy catalyst with C@PtGa interface structure was synthesized under H-2/CO2 atmosphere by using PtCl62/MgAlGa-LDHs as precursor. Cs-corrected STEM, EELS and CO chemisorption clearly confirmed the PtGa alloy particles were well covered by amorphous carbon thin layer with the characteristics of porous and permeable. In selective cinnamaldehyde hydrogenation, the C@PtGa catalyst showed a higher selectivity than both bare PtGa catalyst and Ga2O3@PtGa catalyst. The enhanced selectivity was attributed to the geometric decoration of carbon layer as well as the formation of electron-rich Pt sites at C@PtGa interface, which optimized the adsorption mode of cinnamaldehyde. More importantly, the permeable characteristic of carbon layer which maintained the accessibility of reactants to the Pt sites, contributed to the higher conversion compared to Ga2O3@PtGa catalysts with traditional oxide interface layer. Additionally, C@PtGa catalyst exhibited a good reusability with conversion of 88.3% and selectivity of 91.9% after 5 cycles. This work provides an alternative way to realize the boost of activity and selectivity in selective hydrogenation of C=O bonds by intelligently fabricating non-oxides@metal interface. (c) 2020 Elsevier Inc. All rights reserved.