SusChEM: Promotion of Nickel Catalysts for the Conversion of Biomass-derived Oils to Fuel-like Hydrocarbons

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

Proposed Abstract Title: SusChEM: Development of Nickel Catalysts for the Conversion of Biomass-derived Oils to Fuel-like Hydrocarbons Biodiesel, which consists of fatty acid methyl esters or so-called FAMEs, is a fuel derived from vegetable oils and animal fats which has gained much attention in recent years as a renewable alternative to diesel fuel. However, a number of issues stemming from the high oxygen content of biodiesel,such as relatively poor storage stability and engine compatibility issues, have limited its widespread application, along with a lack of suitable feedstocks. This award, to Professors Mark Crocker and Eduardo Santillan-Jimenez at the University of Kentucky Center for Applied Energy Research, aims to circumvent these shortcomings by developing an improved process for the conversion of vegetable oils and animal fats to hydrocarbons which are chemically indistinguishable from petroleum-derived diesel, and hence, which can be used as a drop-in substitute for diesel. A key feature of this process is the use of a catalyst based on inexpensive, earth-abundant nickel, as opposed to the use of expensive precious metal catalysts. An added benefit of this research is that it will provide students with hands-on experience in the field of biofuels, thus ultimately helping to satisfy the growing demand for highly skilled scientists and engineers in the renewable energy sector. A second objective of this project is the establishment of new outreach efforts directed at local Kentucky schools. Specifically, a "biofuels game" will be developed, which teaches K-12 students basic concepts about petroleum fuels, biofuels, and the relative economic and environmental costs associated with their production and use. The entire focus of the award is aligned with the SusChEM philosophy. Catalytic decarboxylation/decarbonylation (deCOx) has been proposed as an alternative to hydrotreating for the conversion of lipids and bio-oils to produce renewable drop-in hydrocarbon fuels. Indeed, deCOx is not only more energy and hydrogen efficient, but it proceeds over benign metal catalysts, and does not require the sulfided catalysts used in hydrotreating. The investigators have shown that the performance of specific catalysts comprising earth-abundant and inexpensive Ni can rival that of the expensive precious metals (Pd and Pt) commonly used to catalyze deCOx. Preliminary results have shown that promotion of Ni catalysts with small amounts of Cu or Sn leads to enhancements in the efficiency of the process. However, the underlying principles of the catalytic phenomena at play are not thoroughly understood. This project aims at a more complete understanding of these promotion effects, which in turn should allow further improvements to the system. To this end, four main objectives will be addressed: 1) the selectivity of Ni catalysts towards fuel-like hydrocarbons will be optimized by fine-tuning the activity of the catalytically active phase; 2) the resistance to deactivation shown by these catalysts will be improved by modifying the active phase electronically and/or morphologically; 3) fundamental structure-activity relationships will be established to rationalize the effect of these changes on the active phase; and 4) mechanistic and kinetic studies will be employed to elucidate the reaction mechanism and kinetic parameters for representative feed-catalyst combinations.