Electronic Metal‐Support Interaction Strengthened Pt/CoAl‐LDHs Catalyst for Selective Cinnamaldehyde Hydrogenation

Abstract

Abstract Cinnamaldehyde (CAL) is a typical sustainable biomass molecule which is classified as α, β‐unsaturated aldehydes. Selective hydrogenation of CAL to produce high‐value and fine chemical cinnamylalcohol (COL) is an attractive catalytic transformation process. However, the hydrogenation of C=O bond in CAL is more unfavorable than C=C bond in thermodynamics and kinetics, leading to great challenge on achieving high yield of unsaturated alcohol. In this work, a Pt/CoAl‐LDHs catalyst was prepared for hydrogenation of CAL to COL, showing outstanding intrinsic activity (TOF as high as 4.93 s −1 ) and finally achieving 93.6 % selectivity at 95.4 % conversion. In contrast, the yields of COL over Pt/Co(OH) 2 and Pt/Al(OH) 3 were only 73 % and 34 % respectively. Characterizations including Raman, O‐XAFS, XPS revealed that the Co 2+ −O 2− −Al 3+ structure in CoAl‐LDHs contributed to strengthened metal‐support interactions, and resulted in electron‐rich and geometric decoration Pt δ− sites. The electron‐rich Pt δ− provided preferable H 2 activation capability, and also exposed abundant unsaturated sites which optimized the adsorption mode of cinnamaldehyde favorable for C=O hydrogenation. However, in Pt/Co(OH) 2 and Pt/Al(OH) 3 catalysts, the Pt 0 without electron‐rich and unsaturated property cannot improve the H 2 activation capability as well as electronic repellency to C=C bond. In addition, a possible catalytic mechanism was proposed to illustrate the role of Pt δ− −Co 2+ −O 2− −Al 3+ interfacial structure on enhancing activity and selectivity.