Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Jonalyn A. Fair - Southern University and A&M College
Co-Author(s): Raluchukwu T. Onwubuya, Allen University, Andre J. Spears, Southern University and A&M College, Joseph H. Dumont, Los Alamos National Laboratory, T. Rockward, Los Alamos National Laboratory
Platinum (Pt) is the state-of-the-art catalyst for both anodic and cathodic reactions that occur in polymer electrolyte fuel cells (PEMFCs). Due to the cost of platinum, fuel cells have been hindered from commercialization. However, one obstacle for next generation fuel cells is to reduce the amount of platinum yet still produce tremendous activity and high durability. In this work we have investigated the effects of aging, with the use of an Accelerated Stress Test (AST) that consists of voltage cycles from 0.6 V to 1.0 V vs. RHE. Furthermore, we studied the electrochemically active surface area (ECSA) of different Pt loadings on carbon. In particular, we used a catalyst supported on a high surface area carbon, XC-72. We tested Pt catalyst of 4.8%, 20%, and 40%. These materials are used in the state-of-the-art PEMFCs. To study the activity and durability of the Pt catalyst, a rotating ring disk electrode (RRDE) system is used in stationary mode. Carbon monoxide (CO) is introduced into the RDE system because it is adsorbed onto Pt active sites and the ECSA of the catalyst can be calculated. The number of active sites can be determined by measuring the ECSA of the hydrogen adsorption and desorption regions, and CO stripping. Detailed examination of the results reveal that the various loadings of Pt on carbon supported do have an impact on the active sites. This was validated by the decrease in ECSA as the loading of Pt on carbon increased. In all tests, we observed ECSA losses as the number of AST voltage cycles increased.Not Submitted
Funder Acknowledgement(s): LANL – Consortium of Materials and Energy Security (CMaES) NNSA Minority Serving Institutes Program: Corey Jackson and Dr. Dimitri Kusnezov Dr. Diola Bagayoko & Southern University & A&M College Dr. Anthony Stewart & Allen University
Faculty Advisor: Dr. Diola Bagayoko, Bagayoko@aol.com
Role: Before being hands-on, I partook in an electrochemistry short course and a series of laboratory training including gas bearing assembly, gas chamber (bottle) changing, and personal protection equipment. In this research, I aided in the drafting of the research parameters. With the supervision of my mentors, I conducted the Cyclic Voltammetry Experiments, Rotating Ring Disk Three-Electrode Set Up, Routine Machinery Maintenance (Polishing Working Electrode, Mixing and Depositing Uniform Catalyst Ink Layer), ECSA Measurements, Data Presentation, and the poster's wording and placement of content.