Single-Atom Enables Reverse Hydrogen Spillover for High-Performance Protonic Ceramic Fuel Cells.

Zhao, Sunce; Ma, Wenjia; He, Beibei; Ling, Yihan; Huang, Yonglong; Hu, Feng; Shu, Zhu; Zhao, Ling · Adv Mater · 2025

basic_science · Level V

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Abstract

Protonic ceramic fuel cells (PCFCs) offer a promising avenue for sustainable energy conversion, however, their commercial potential is hindered by sluggish proton-involved oxygen reduction reaction (P-ORR) kinetics and inadequate durability of cathode materials. Here, a novel single-atom Ru anchor on BaCe<sub>0.125</sub>Fe<sub>0.875</sub>O<sub>3-δ</sub> (BCF) perovskite, synthesized by a facile and scalable solid-state approach, as a potential cathode for PCFCs is reported. Theoretical and experimental analyses demonstrate that the single-atom Ru on BCF, characterized by a unique 4-coordinate Ru-O-Fe configuration, not only induces reverse hydrogen spillover but also acts as an active site for P-ORR. The application of the optimized 2Ru-BCF (2 wt.% Ru) cathode in a single cell delivers an exceptional peak power density of 1.78 W cm<sup>-2</sup> at 700 °C, along with excellent operational stability over 200 h. These findings provide new insights into single-atom engineering, advancing the commercial viability of PCFCs.