Extraordinary Activity of Nanodispersed Bimetallic NiFe Phosphide Catalysts for the Conversion of a Biomass Model Compound

S.T. Oyama, A. Cho, J. Shin, A. Takagaki, R. Kikuchi
The University of Tokyo, JP

Keywords: biomass conversion, catalysis, nickel phosphide, hydrodeoxygenation

Summary:

The present work deals with the development of new catalysts, transition metal phosphides, which have outstanding activity for hydrodeoxygenation of pyrolysis oil. The study is significant as it leads to the production of high-energy content liquid fuels. Pyrolysis of biomass is a thermal conversion process that produces liquid fuels and chemicals, and is a promising technology to compete with and eventually replace non-renewable fossil fuels. Pyrolysis liquids are formed quickly and at relatively low temperatures, but contain significant oxygen (~40 wt.%) which causes low heating value (about half that of petroleum liquids), high acid content (leading to corrosion problems), and low stability (resulting in increasing viscosity with storage). The model substrate 2-methyltetrahydrofuran is studied by kinetic and spectroscopic methods to uncover the important steps involved in the reaction. On the most active catalyst, Ni2P, the studies indicate that the rate-determining step involves a single Ni atom. In situ infrared measurements are used to identify adsorbed reactive intermediates during reaction and give support for the reaction mechanism. The studies are important because they allow understanding of reactivity at a nanoscale level and lead to the design of more active catalysts.