EAGER: Viologen-catalyzed Electrochemical Conversion of Biomass for Sustainable Energy and Products

Brigham Young University, Provo UT

Investigators

Abstract

Harb, 1540537 Carbohydrates from biomass have the potential to generate renewable energy for electric automobiles and other power-consuming needs. Current challenges inhibiting this technology include the low power output and insufficient catalyst durability of biofuel cells, and low carbohydrate conversion in non-biological fuel cells. A transformative breakthrough has come with the discovery of a homogeneous non-biological viologen catalyst that enables almost complete carbohydrate conversion. The overall objective of this project is to explore the feasibility of using this breakthrough to produce sustainable energy through biomass conversion in an electrochemical reactor. This preliminary feasibility study will identify the key fundamental processes and constraints that will determine the design and operation of a reactor system to produce sustainable energy, fuel or biochemical products. Four tasks have been defined to accomplish this objective. Task 1 will determine whether the homogenous and heterogeneous reaction rates can be effectively balanced to obtain the current density needed for a sustainable, economically viable process. Experiments under controlled flow conditions will the influence of pH, reactant concentrations, temperature, and potential. Task 2 will explore strategies, informed by the conditions identified in Task 1, for promoting near-complete carbohydrate conversion in a practical reactor system. Task 3 will assess the feasibility of hydrogen production as an alternative to electricity production. Viologens with more negative redox potentials will be evaluated as possible catalysts. Finally, Task 4 will identify and quantify fundamental properties and limitations of the proposed electricity or hydrogen generating system based on results from the previous tasks. The possibility of using separate reactors for the homogeneous and heterogeneous reactions will also be explored as part of this task to potentially enable greater efficiency and additional, transformative products. Completion of this preliminary study will 1) determine if the newly discovered viologen catalyst can be used for carbohydrate conversion at high rates (current density) in order to justify further consideration of this system as part of a full proposal, 2) identify a reactor strategy by which it may be possible to produce electricity from near-complete conversion of a carbohydrate, and 3) explore the feasibility of using carbohydrates to generate hydrogen. Fundamentally, this research will examine the interaction of homogeneous biomass reactions, a heterogeneous electrochemical reaction, and the reaction conditions in order to achieve potentially conversion of carbohydrates to produce sustainable energy. Fundamental issues related to carbon removal in the form of carbonate will also be explored in the context of potential reactor strategies. It is expected that the results of this study could have a far-reaching impact on the development of viable and sustainable biomass conversion strategies, with emphasis on energy and transportation fuels. Inherent is the potential benefit of multiple platforms (electricity, hydrogen, and biologically reactive species) utilizing near-complete conversion of carbohydrates to increase the appeal for development of biomass-based economies. Increased adoption and sustained use of biomass-based processes from dedicated energy crops could (i) reduce dependence on other energy resources such as petroleum, (ii) reduce the impact of fossil fuels on global climate change, and (iii) reduce the use of food crops currently dedicated for biofuel production. Both graduate and undergraduate students, including those from underrepresented groups, will (i) gain experience in the design and implementation process for use of renewable resources (ii) demonstrate an appreciation for working within engineering constraints to develop a sustainable process, (iii) demonstrate effective teamwork and leadership skills as they work together as a team, and (iv) recognize the extent to which renewable resources can be applied to multiple process platforms.