Comparative study on the reaction mechanism of 5-hydroxymethyl furfural on Pd(111) and Cu(111)

Abstract

Context In this paper, the comparative study on the catalytic conversion of 5-hydroxymethyl furfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) on precious Pd(111) and non-precious Cu(111) was systematically studied using periodic density functional theory (DFT) including zero-point energy (ZPE) correction and dispersion correction. Based on the calculated activation energy (Ea) and reaction energy (Er), it was concluded that the optimal energy path for the HMF (F-CHO) conversion to BHMF (F-CH2OH) on Pd(111) is as follows: F-CHO + 2H → F-CHOH + H → F-CH2OH; and the minimum reaction path on Cu(111) is: F-CHO + 2H → F-CH2O + H → F-CH2OH. On Cu(111), the formation of F-CH2OH from F-CH2O hydrogenation displays the highest reaction energy barrier and the smallest rate constant so that it is the rate-determining step. The comparison of HMF hydrogenation on Pd(111) and Cu(111) reveals their inherent differences in selectivity mainly due to the different adsorption geometries of HMF and BHMF, and it was concluded the non-precious Cu(111) is a promising hydrogenation catalyst for the production of BHMF from the hydrogenation of HMF. Methods All plane-wave DFT calculations were performed by using Vienna ab initio simulation package (VASP, version 5.3.5). The exchange and correlation energies were computed using the generalized gradient approximation (GGA) of Perdew, Burke and Ernzerhof (PBE) functional with the projector augmented wave (PAW) method.