Tuning SMSI for DDO of phenolics: SMSI alters the density and property of sites at the interfacial perimeter of metal/oxide catalyst, which can be used to tune the hydrodeoxygenation reaction that happens at the interface and requires multiple functionalities. We reviewed the advances in tuning the SMSI for enhancing direct deoxygenation of biomass-lignin derived phenolics, with special attention on the origin of SMSI and its consequence on DDO.

Abstract

Catalytic direct deoxygenation (DDO) of phenolic compounds to aromatics is an appealing approach for utilization of biomass-lignin with minimal amount of H₂ consumption. Metal/reducible metal oxide catalysts provide two functionalities, i. e., C−H bond formation (hydrogenation) and C−O bond breakage (deoxygenation), required for this reaction that takes place at the interfacial perimeter sites. Strong metal-support interactions (SMSI) can profoundly alter the density and property of such sites. This short review summarized recent advances in tuning SMSI for enhancing DDO of phenolics. The approaches of varying reduction temperature, modulation of crystal facets and crystal phases of metal oxide, and reduction of mixed metal oxide were discussed for the origin for formation of SMSI, the degree of SMSI, and its consequence on the DDO performance. The analysis revealed that intermediate degree of SMSI with maximal density of metal/oxide interfacial perimeter site enhances DDO while minimizing unfavorable side reactions. This short review highlights the concept of tuning the interfacial perimeter sites via SMSI for reactions which require multiple functionalities and take place at the metal/oxide interface.