Adsorption and decarbonylation reaction of furfural on Pt(111) surface

Abstract

The reaction mechanismof furan formation during decarbonylation of furfural on the Pt(111) plane was investigated by density functional theory generalized gradient approximation calculations with the slab model. The adsorption energy of furfural was calculated to determine preferred adsorption sites on the Pt(111) plane. The revealed possible mechanisms for the decarbonylation of furfural on the Pt(111) plane were studied. The results showed that a furfural molecule loses 0.765 electrons after adsorption on the Pt(111) surface. The d orbitals of the metal surface interact strongly with the π bonds of the furfural ring. This reduced the aromaticity of the furfural ring and theCatoms showed characteristics consistent with sp3 hybridization. The molecular plane of the adsorbate was distorted, and corresponding changes of bond lengths were found. The C-H(O) bonds and-CHOof furfural tilted away fromthe Pt surface. The calculations showthat furan was a possible product of the decarbonylation reaction. We then searched the transition states (TSs) and reaction potential energy surfaces with the linear and quadratic synchronous transit (LST/QST) complete search. By comparing energy barriers, we obtained the optimal path, which involved furfural forming an acyl intermediate by loss of theHatom from the branched chain rather than direct decarburization. Furan was then formed by decarburization and hydrogenationof the acyl intermediate. Thecalculated barrier for the rate-determining step(C4H3O)CO*+*→C4H3O*+CO* (* is adsorption site) is 127.65 kJ-mol-1. © Editorial office of Acta Physico-Chimica Sinica.