Interfacial synergy at Ni-NiO interfaces for rapid and selective vanillin hydrodeoxygenation

Efficient hydrodeoxygenation (HDO) of biomass-derived phenolics relies on the effective coupling of hydrogen activation and C-O bond cleavage. Here, we report a Ni-NiO interfacial catalyst that enables interfacial synergy by integrating hydrogenation and deoxygenation functions within a confined nanoscale interface. By tailoring the reduction temperature of NiO/Al 2 O 3 , the Ni/NiO ratio is precisely controlled, with the catalyst reduced at 400 °C exhibiting highly dispersed Ni species intimately interfaced with NiO. Mechanistic studies suggest that hydrogen dissociated on metallic Ni can spill over to adjacent NiO, generating interfacial hydrogen species and enhanced acidity that facilitate C-O bond cleavage. Meanwhile, the close proximity of Ni and NiO enables efficient coupling of the hydrogenation and deoxygenation functions, thereby promoting rapid tandem conversion at the interface and lowering the apparent activation barrier for vanillin HDO.