Crystal-Phase-Engineering of PdCu Nanoalloys Facilitates Selective Hydrodeoxygenation at Room Temperature

ABSTRACT Selective hydrodeoxygenation of biomass-derived aromatic alcohols to value-added chemical or fuel is of great importance for sustainable biomass upgrading and hydrodeoxygenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) is one of the most attractive reactions. Achieving the conversion of HMF to DMF using H2 at ambient temperature is challenging. In this work, we used PdCu nanoalloys to catalyze the selective hydrodeoxygenation reaction of HMF to DMF using H2 as the reducing agent. The reaction path and the product selectivity are governed by crystallographic phase of the PdCu nanoalloys. It was discovered that body-centered cubic (BCC) PdCu nanoalloys supported on activated carbon (AC) exhibited outstanding performance with 93.6% yield of DMF at room temperature (PdCu/AC-BCC). A combination of experimental and density function theory (DFT) studies showed that the tilted adsorption modes of furanic intermediates on PdCu-BCC nanoalloy surfaces accounted for the high selectivity of DMF, however furan ring was activated on PdCu-FCC (FCC: face-centered cubic) nanoalloy surfaces. Furthermore, PdCu/AC-BCC could also catalyze the hydrodeoxygenation of other aromatic alcohols at room temperature while maintaining the aromatic structures. This work opens the way for selective hydrodeoxygenation of the aromatic alcohols at room temperature with the aromatic ring intact.