Selective Hydrogenation of Cinnamaldehyde to Cinnamal Alcohol over Platinum/Graphene Catalysts

Catalysts made of Pt nanoparticles dispersed on graphene ( X  wt %Pt/G, X =2.0, 3.5, and 5.0) were prepared and characterized by XRD, Raman spectroscopy, BET surface area measurements, TEM, and X‐ray photoelectron spectroscopy (XPS), and a 3.5 wt % Pt supported on Vulcan Carbon catalyst (3.5 wt %Pt/VC) was included as a reference. Although the mean Pt nanoparticle size is approximately 4.4 nm for all X  wt %Pt/G and 3.5 wt %Pt/VC catalysts, cinnamal alcohol was produced with high selectivity only with the graphene‐supported catalysts: 92 % conversion and 88 % selectivity toward cinnamal alcohol were obtained with 3.5 wt %Pt/G. This catalyst also showed good stability in recycling tests. The good selectivity observed with the graphene‐based catalysts is attributed to the higher fraction of reduced surface Pt 0 atoms seen on the surface of the Pt nanoparticles (determined by XPS). This interpretation is consistent with DFT calculations. Additional π–π interactions between cinnamaldehyde and graphene may also play a role in the selective hydrogenation of cinnamaldehyde.