Co-sputtered Pt/Ti alloy cathode for low-temperature solid oxide fuel cell

One of the effective strategies to enhance the activity and stability of the Pt-based catalysts in low-temperature solid oxide fuel cells (LT-SOFCs) is modifying the electronic structure and reducing the surface energy of Pt by transition metal alloying. Herein, co-sputtered Pt/Ti alloy cathodes for LT-SOFC with varying Pt/Ti compositional ratios (Ti 0-26 at%) are fabricated and tested. The cell constructed with the optimal (6-11 at% Ti) Pt/Ti alloy cathode shows five times lower degradation rate in activation resistance compared to a pure Pt cathode at 450 degrees C, resulting in a 33% enhancement in the maximum power density after 2 h of operation. We show that the performance enhancement of the Pt/Ti alloy cathode at elevated temperature is due to the formation of a catalytically active and thermally stable Pt3Ti alloy phase, in which coarsening is effectively prevented as opposed to its pure Pt counterpart. Moreover, we demonstrate that Pt/Ti alloy cathodes with excessive Ti content (>= 19 at%) suffer from the formation of a nonreactive TiO2 surface upon oxygen exposure at elevated temperature, which causes higher activation resistance. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Modifying the electronic structure and reducing the surface energy of Pt through transition metal alloying is an effective strategy to enhance the activity and stability of Pt-based catalysts in low-temperature solid oxide fuel cells (LT-SOFCs). In this study, co-sputtered Pt/Ti alloy cathodes with varying Pt/Ti compositional ratios (Ti 0-26 at%) were fabricated and tested. The results showed that the cell with the optimal Pt/Ti alloy cathode demonstrated a five times lower degradation rate in activation resistance compared to a pure Pt cathode at 450 degrees C, resulting in a 33% enhancement in the maximum power density after 2 hours of operation. The performance enhancement of the Pt/Ti alloy cathode at elevated temperature was attributed to the formation of a catalytically active and thermally stable Pt3Ti alloy phase.