CAREER: Low-Dimensional Reactive Hydrides for the Efficient Electro-hydrogenation of Aromatic and Aliphatic Hydrocarbons

Drexel University, Philadelphia PA

Investigators

Abstract

The chemical and petroleum industries account for 46% of the yearly energy consumption in the U.S. industrial sector. A reduction in energy consumption by these industries would have a significant impact on future energy supply. This research project investigates electrochemical methods for reacting organic molecules with hydrogen through a process known as electrochemical hydrogenation. Electrochemical hydrogenation has potential to replace the more energy intensive thermal/chemical hydrogenation processes that currently dominate the chemical and petroleum industries. Electrochemical hydrogenation technologies open the door to improvements in energy efficiencies and to the use of renewable chemical feedstocks, thereby decreasing carbon emissions. This research project focuses on the role that catalysts can play in advancing electrochemical system design as a means to improve process efficiency and lower the costs of running the system. The project will provide both graduate and undergraduate students a fundamental foundation in electrochemical science research. Through a partnership with the Lindy Center at Drexel University, freshman engineering students will design lab modules to teach the principles of electrochemical energy storage and conversion to local grade 6-12 students through a Science Saturdays program. Electrochemical hydrogenation has several advantages over thermal/chemical hydrogenation, namely: (1) water is the source of hydrogen, (2) low operational temperature/pressure, and (3) control of activity/selectivity with applied potential. The development of next-generation electrochemical hydrogenation catalysts requires (1) strategies to manipulate bulk hydride reactivity through a more fundamental understanding of their reactivity descriptors, and (2) more detailed insight into the effect of the electrochemical interface on aromatic/aliphatic reactant adsorption, adsorbed intermediate solvation, and direct hydrogenation by near surface water. While transition metal hydrides have been used for high temperature, heterogeneous hydrogenation/dehydrogenation catalysis, their transition to electro-hydrogenation has been slow. Limiting this transition has been an absence of analysis of the direct effect of specific material properties, particularly hydride properties, on both activity and selectivity. This research project will identify the interrelation between chemical properties of the organic reactant, intrinsic catalyst properties, and electric field established at the metal/electrolyte interface, to guide the design of systems for the selective electrochemical hydrogenation of specific organic reactants. The project also will build a base for future research centered on exploitation of electrochemical interfaces as a tool to address limiting processes including adsorbed reactant solvation, intermediate scaling, and imbalance between activity, selectivity, and durability. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.