Mechanistic exploration of furfural hydrogenation on copper surface in aqueous phase by DFT and AIMD simulations

•The furfural hydrogenation mechanisms are systematically investigated in vapor phase and aqueous phase.•A proton-shuttling mechanism in aqueous phase is proposed.•The presence of water enhances the stability and activity of reaction intermediates.•The dynamic charge separation between the catalyst and the intermediates results in low hydrogenation barriers.