A variety of electrochemical energy conversion technologies, including fuel cells, rely on solution-processing techniques (via inks) to form their catalyst layers (CLs). The CLs are heterogeneous structures, often with uneven ion-conducting polymer (ionomer) coverage and underutilized catalysts. Various platinum-supported-on-carbon colloidal catalyst particles are used, but little is known about how or why changing the primary particle loading (PPL, or the weight fraction of platinum of the carbon–platinum catalyst particles) impacts performance. By investigating the CL gas-transport resistance and zeta (ζ)-potentials of the corresponding inks as a function of PPL, a direct correlation between the CL high current density performance and ink ζ-potential is observed. This correlation stems from likely changes in ionomer distributions and catalyst–particle agglomeration as a function of PPL, as revealed by pH, ζ-potential, and impedance measurements. These findings are critical to unraveling the ionomer distribution heterogeneity in ink-based CLs and enabling enhanced Pt utilization and improved device performance for fuel cells and related electrochemical devices.
BT - ACS Applied Materials & Interfaces DA - 08/2022 DO - 10.1021/acsami.2c10499 IS - 32 LA - eng N2 -A variety of electrochemical energy conversion technologies, including fuel cells, rely on solution-processing techniques (via inks) to form their catalyst layers (CLs). The CLs are heterogeneous structures, often with uneven ion-conducting polymer (ionomer) coverage and underutilized catalysts. Various platinum-supported-on-carbon colloidal catalyst particles are used, but little is known about how or why changing the primary particle loading (PPL, or the weight fraction of platinum of the carbon–platinum catalyst particles) impacts performance. By investigating the CL gas-transport resistance and zeta (ζ)-potentials of the corresponding inks as a function of PPL, a direct correlation between the CL high current density performance and ink ζ-potential is observed. This correlation stems from likely changes in ionomer distributions and catalyst–particle agglomeration as a function of PPL, as revealed by pH, ζ-potential, and impedance measurements. These findings are critical to unraveling the ionomer distribution heterogeneity in ink-based CLs and enabling enhanced Pt utilization and improved device performance for fuel cells and related electrochemical devices.
PY - 2022 SP - 36731 EP - 36740 ST - ACS Appl. Mater. Interfaces T2 - ACS Applied Materials & Interfaces TI - Impact of Platinum Primary Particle Loading on Fuel Cell Performance: Insights from Catalyst/Ionomer Ink Interactions UR - https://pubs.acs.org/doi/10.1021/acsami.2c10499 VL - 14 SN - 1944-8244 ER -