Ultrastable and Phosphoric Acid-Resistant PtRhCu@Pt Oxygen Reduction Electrocatalyst for High-Temperature Polymer Electrolyte Fuel Cells
Zhao An, Huanqiao Li, Xiaoming Zhang, Zhangxun Xia, Hong Zhang, Wenling Chu, Shansheng Yu, Suli Wang, Gongquan Sun
Abstract
With much enhanced fuel flexibility to overcome the shortcomings of hydrogen production and storage, high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are still facing challenges of activity loss of oxygen reduction electrocatalyst under the working circumstance of phosphoric acid (PA) electrolyte. Dissolution and leaching of metal component of PtM (M = Cu, Co, Ni···) electrocatalysts is one of the key factors that degrade their initial resistance toward PA and hinder the accessing of activity and durability simultaneously. Here, we report an ultradurable PtRhCu@Pt/C electrocatalyst with a high mass activity of 0.90 A mg –1 Pt, which only decreased by 14.4% after 30K ADT cycles in the half-cell and reaches the DOE at 2025 target (<30 mV at 0.8 A cm –2 ) with 27 mV voltage loss at 0.8 A cm –2 in the single-cell. After adding 0.1 M PA into the electrolyte, the half-wave potential of PtRhCu@Pt/C is negatively shifted by only 52 mV, much lower than that of commercial Pt/C (90 mV). Moreover, the HT-PEMFC assembled by this catalyst delivers a preeminent peak power density of 529 and 977 mW cm –2 under H 2 –air and H 2 –O 2 conditions, respectively. Experiments and theoretical calculations reveal that the ligand effect arising from the sublayer Cu is attributed to the ability of PA resistance, while the self-healing behavior and the synergy between the PtRhCu core and the Pt shell ensures high stability.