Ceria tubular nanoarchitecture antioxidants achieve sustainable fuel cell devices via tuning the oxophilicity of Pt catalytic surfaces and radical scavenging

Abstract

The durability of polymer electrolyte membrane fuel cells (PEMFCs) crucially depends on the use of antioxidants to prevent electrocatalyst degradation. Here, we report for the first time, by in situ X-ray absorption and H2O2 electrochemistry, that ceria significantly weakens the Pt-surface oxophilicity, which determines oxygen reduction (ORR) activity and durability, within the PEMFC cathode. Ceria mitigates catalyst disintegration and improves ORR durability by Pt oxophilicity reduction and its inherent radical scavenging behavior. We also found that the antioxidation efficacy of ceria could be finely tuned through nanostructuring. Among various ceria nanostructures, tubular ceria nanoarchitectures (CeOx NT), designed to have the largest surface area and abundant oxygen vacancies, enable the most potent interaction between Pt and Ce without direct chemical contact with Pt. The nanotubular structure confers superior multifunctional antioxidant therapeutic efficacy to Pt/C catalyst in PEMFCs, resulting in outstanding durability that retains 94% of initial performance after 100-hour tests.