Public Abstract

DE-SC0016529: Peptide Control of Electrocatalyst Surface Environment and Catalyst Structure: A Design Platform to Enable Mechanistic Understanding and Synthesis of Active and Selective N2 Reduction Catalysts

Award Status: Inactive

Institution: University of Arkansas, Fayetteville, AR
UEI: MECEHTM8DB17
DUNS: 191429745

Most Recent Award Date: 07/23/2018
Number of Support Periods: 3
PM: Schwartz, Viviane

Current Budget Period: 09/15/2018 - 09/14/2019
Current Project Period: 09/15/2016 - 09/14/2019
PI: Greenlee, Lauren

Supplement Budget Period: N/A

Public Abstract

Peptide Control of Electrocatalyst Surface Environment and Catalyst Structure: A Design Platform to Enable Mechanistic Understanding and Synthesis of Active and Selective N₂ Reduction Catalysts Lead PI: Dr. Lauren F. Greenlee, Assistant Professor Ralph E. Martin Department of Chemical Engineering University of Arkansas Fayetteville, AR 72701 Co-Investigator: Julie N. Renner, Assistant Professor Department of Chemical and Biomolecular Engineering Case Western Reserve University Cleveland, OH 44106 Co-Investigator: Michael J. Janik, Professor Department of Chemical Engineering The Pennsylvania State University State College, PA 16802 The primary means for synthesizing ammonia (NH₃) is through the Haber-Bosch process, where nitrogen gas (N₂) and hydrogen gas (H₂) are combined at high temperature and pressure. The source of hydrogen is methane (natural gas) steam reforming, where carbon-based methane (CH₄) is reacted with steam (water) to form hydrogen. However, the other reaction product is carbon dioxide (CO₂), making the overall process of ammonia production one of the largest producers of greenhouse gases worldwide. Furthermore, Haber-Bosch ammonia production is energy intensive, requires large capital investment, and has many process steps. With the continued growth in world population and concurrent strain on agricultural resources, fossil fuel resources, and environmental health, there is an urgent need for alternative approaches to enable a more sustainable ammonia synthesis process. Electrochemical reduction of humidified N₂ to NH₃ may be a viable route to low-temperature, CO₂-free ammonia generation, but current electrocatalysts are plagued by extremely low selectivity, and thus efficiency, due to competition with electrochemical reduction of water to hydrogen. The premise of this project is that control of the local surface environment of these electrocatalysts may enable enhanced selectivity for N₂ reduction over H₂ evolution. In this project, small-chain peptides comprised of specific amino acid sequences will be explored as a design platform for both controlling local catalyst electrochemical environment and understanding the key steps of the N₂ electroreduction reaction mechanism. In particular, amino acids will be chosen to control hydrophobicity and proton shuttling at the catalyst surface. Fundamental measurements of N₂ adsorption, water vapor adsorption, electrochemical performance, and peptide stability will be coordinated with theoretical model development with the goal of establishing initial predictors for ligand/catalyst environments that enable selective and active N₂ reduction electrocatalysts.

Peptide Control of Electrocatalyst Surface Environment and Catalyst Structure: A Design Platform to Enable Mechanistic Understanding and Synthesis of Active and Selective N₂ Reduction Catalysts

Lead PI: Dr. Lauren F. Greenlee, Assistant Professor
Ralph E. Martin Department of Chemical Engineering
University of Arkansas
Fayetteville, AR 72701

Co-Investigator: Julie N. Renner, Assistant Professor
Department of Chemical and Biomolecular Engineering
Case Western Reserve University
Cleveland, OH 44106

Co-Investigator: Michael J. Janik, Professor
Department of Chemical Engineering
The Pennsylvania State University
State College, PA 16802

The primary means for synthesizing ammonia (NH₃) is through the Haber-Bosch process, where nitrogen gas (N₂) and hydrogen gas (H₂) are combined at high temperature and pressure. The source of hydrogen is methane (natural gas) steam reforming, where carbon-based methane (CH₄) is reacted with steam (water) to form hydrogen. However, the other reaction product is carbon dioxide (CO₂), making the overall process of ammonia production one of the largest producers of greenhouse gases worldwide. Furthermore, Haber-Bosch ammonia production is energy intensive, requires large capital investment, and has many process steps. With the continued growth in world population and concurrent strain on agricultural resources, fossil fuel resources, and environmental health, there is an urgent need for alternative approaches to enable a more sustainable ammonia synthesis process. Electrochemical reduction of humidified N₂ to NH₃ may be a viable route to low-temperature, CO₂-free ammonia generation, but current electrocatalysts are plagued by extremely low selectivity, and thus efficiency, due to competition with electrochemical reduction of water to hydrogen. The premise of this project is that control of the local surface environment of these electrocatalysts may enable enhanced selectivity for N₂ reduction over H₂ evolution. In this project, small-chain peptides comprised of specific amino acid sequences will be explored as a design platform for both controlling local catalyst electrochemical environment and understanding the key steps of the N₂ electroreduction reaction mechanism. In particular, amino acids will be chosen to control hydrophobicity and proton shuttling at the catalyst surface. Fundamental measurements of N₂ adsorption, water vapor adsorption, electrochemical performance, and peptide stability will be coordinated with theoretical model development with the goal of establishing initial predictors for ligand/catalyst environments that enable selective and active N₂ reduction electrocatalysts.