Highly Active Cathode Achieved by Constructing Surface Proton Acid Sites through Electronic Regulation of Heteroatoms
Xinyu Li, Zemin Chen, Daoming Huan, Bingbing Qiu, Kang Zhu, Zeming Qi, Hengjie Liu, Changrong Xia, Ranran Peng, Yalin Lu
Abstract
For proton-conducting solid oxide fuel cells (PCFCs), accelerating the kinetics of the proton involved oxygen reduction reaction (P-ORR) occurring primarily on the surface of cathodes is of key importance. To this end, developing simple, efficient, and economical strategies to optimize the gas–solid interface is crucial but full of challenges. Herein, the heteroatom boron (B) is first introduced to modify the PCFC cathode surface (Pr 4 Ni 3 O 10+δ, PN) by mechanical mixing method (0.5B-PN). Combined with in situ/ex situ characterizations and DFT calculation, it is found that the CO 2 resistance, surface hydration ability, and surface electrocatalytic activity toward P-ORR are significantly improved by B decoration. Importantly, the B element is found to raise the surface Brønsted acid (−OH) concentration yet depress the surface Lewis acidity, both of which are conducive to P-ORR reaction. At 600 °C, the maximum power density of the cell using 0.5B-PN as the cathode improved by 149.5% compared with that using the PN cathode. This work opens up a new avenue for developing novel PCFC cathodes via nonmetallic regulation of surface.