PGM-free Engineered Framework Nano-Structure Catalysts

Recipient Greenway Energy LLC (PI: Ganesa, Prabhu)

Subs Savannah River National Laboratory (SRNL), Northwestern University (NU), Case Western Reserve University (CWRU)

Abstract Most traditional synthesis methodologies that produce highly active, PGM-free electrocatalysts typically consist of a top-down approach utilizing a nitrogen coordinating precursor, a metal precursor, and a support material. Nitrogen coordinated transition metal complexes are typically absorbed onto a support material which is then activated via high temperature pyrolysis. State- of-the-art catalysts typically require one or more high temperature heat treatments to generate the catalytically active sites, and in the process, control over the active site composition is diminished. Furthermore, in-situ methodologies capable of probing and quantifying the active sites are lacking. These factors contribute to the prevailing paradigm, an Edisonian approach that has only yielded slow, incremental progress towards the goals of high activity and stability while only elucidating a partial understanding of the PGM-free oxygen reduction reaction (ORR) active site and the reaction mechanism. Understanding the composition of the active site is instrumental in advancing the state-of-the-art; logically, a rationally designed, bottom up approach to catalyst synthesis with known functionalities would aid in this endeavor. The concept proposed herein utilizes a rationally designed, bottom up synthesis approach that addresses the lack of knowledge regarding the composition of the active site. Greenway Energy, LLC (GWE) will lead a collaborative effort with Savannah River National Laboratory (SRNL), Northwestern University (NU), and Case Western Reserve University (CWRU), a team which consists of experts in the fields of fuel cell catalyst development, rational synthesis of high surface area materials, and the conceptual development of electrochemical interfaces. The main project objective is to develop durable, highly active, low cost, PGM-free electrocatalysts for polymer electrolyte membrane fuel cells (PEMFCs) through a unique, rationally designed, bottom-up approach, ultimately with the potential to reach cost competitiveness with conventional automobile technologies. The transformative materials developed through this approach will have well defined functionalities and have the following properties in common: high surface area, high pore volume, high atomic nitrogen content with tunable pyridinic/pyrollic ratios, chemically stable, and electrically conductive. Additional performance improvements can be gained through high temperature activation, heteroatom doping, or through the addition of peripheral functional group addition. Materials with well- defined functionalities can facilitate the development and validation of model systems and help gain a better understanding of the ORR catalyst site composition and reaction mechanisms, thereby advancing the state-of-the-art by improving the existing knowledge base. The project is divided into three main tasks which encompass new catalyst development and characterization (Task 1), active site modeling (Task 2), and MEA optimization and fuel cell testing (Task 3). The project will culminate in internal and independent fuel cell testing (deliver six or more MEAs to ElectroCat, each with active area ≥50 cm2 for independent testing and evaluation), demonstrating the capability of the novel catalyst materials of achieving DOE project targets.