Atomic-Scale Understanding for the Role of the Water-Pd and Water-Cu Interfaces in Catalytic Biomass Conversion Involving Furfural

Palladium (Pd) and copper (Cu) are widely used as catalysts for chemical reactions. When Pd or Cu is used in biomass pyrolysis and other relevant catalytic reactions, water or other liquid is usually involved, and the reactions often occur at the liquid-solid interface. It is therefore of great importance to investigate the role of the interface in relevant catalytic reactions in order to understand the reaction mechanisms for biomass conversion. Experimental measurements have shown that furfural on Pd and on Cu (without water) involves different reactions. The propose of this study is to achieve an atomic-scale understanding about the liquid-solid interfaces and the catalytic reactions involving furfural.

The most stable configuration for adsorption of a single water molecule on the Pd surface (vacuum).  Oxygen is down slightly and forms an O-Pd bond. The molecular plane is tilted. The binding energy is 0.26 eV.  Similar configuration is found for water on Cu(111):

The most stable configuration for adsorption of a single furfural molecule on the Pd(111) surface.  The molecular plane, while no longer exact two-dimensional, is almost parallel to the Pd surface. The binding energy: 0.85 eV:

Adsorption of a single furfural molecule on Cu(111). The molecular plane is almost normal to the Cu surface.  Furfural is boned with the surface via the oxygen atoms. The binding energy: 0.25 eV:


The stable bonding configurations of a water molecule and a furfural molecule on Pd and on Cu are determined by first-principles density functional theory.

The dynamics of pure liquid water, the water-Pd interface, as well as the furfural-involved water-Pd interface, is shown by ab initio molecular dynamics simulations.

The obtained results are consistent with available experimental data.