Efficient C = O bond hydrogenation of cinnamaldehyde over PtCu alloy frame: Insight into the morphology and Pt species state

•The wheel-like PtCu NFs deliver more exposed active sites.•The d-band center of Pt was modulated by the addition of Cu.•PtCu NFs with large particle size exhibit flat surface.•PtCu NFs give excellent hydrogenation performance.•The reaction route and mechanism of hydrogenation was revealed. Highly selective hydrogenation of cinnamaldehyde (CAL) to cinnamic alcohol (COL) remains the great challenge due to the co-existence of C = C and C = O bond in CAL. Herein, Al2O3 supported a series of wheel-like PtCux nanoframes (NFs) with varied Pt/Cu ratios were successfully fabricated, featuring unique electronic and geometric structure. Theoretical calculations and characterizations demonstrate that Cu can effectively optimize the d-band center, improve the distribution and utilization of Pt significantly. Compared with pure Pt crystal, PtCu1.21 NFs display the superior catalytic performance with high selectivity towards COL at a CAL conversion of over 99 %. The in-situ Fourier transform infrared (FTIR) spectroscopy reveals that the highly distribution and optimized d-band center of Pt could effectively weaken C = C bond interaction and strengthen the interaction of C = O bond on catalysts surface, boosting C = O bond hydrogenation to COL.