The influence of porous or solid carbon support on catalyst durability of proton exchange membrane fuel cells

The durability of catalysts is heavily influenced by the choice of carbon supports. This study follows U.S. Department of Energy (DOE) testing protocols to evaluate both catalysts and carbon supports, using accelerated degradation tests (ADTs) tailored for catalysts and carbon supports under automotive driving cycles and start-up/shut-down conditions, respectively. Three commercial carbon supports—Ketjen Black ECP-600JD (KB-600), Ketjen Black EC-300J (KB-300), and Vulcan XC-72 (XC-72)—were assessed. Catalysts with KB supports demonstrated superior durability during catalyst-targeted ADTs due to the effective incorporation of platinum (Pt) within their porous structures, preventing Pt migration and agglomeration. Conversely, XC-72, with its solid structure and low surface area, showed increased Pt agglomeration. Interestingly, during carbon support-focused ADTs, XC-72-based catalysts exhibited exceptional durability owing to their impermeable wall structure and higher graphitization, reducing corrosion. Alternatively, KB-based supports, characterized by high surface area, porous structure, and lower graphitization, accelerated corrosion. Consequently, selecting the appropriate carbon support requires thorough consideration in alignment with the specific design goals and operational priorities of fuel cell systems. This highlights the complexity and significance of such decisions.