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

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Protonic ceramic fuel cells (PCFCs) are promising for sustainable energy but face challenges with slow oxygen reduction kinetics and cathode material durability.
• The proton-involved oxygen reduction reaction (P-ORR) is a key bottleneck in PCFC performance.

Purpose of the Study:

• To develop a novel cathode material for PCFCs to overcome limitations in P-ORR kinetics and durability.
• To investigate the efficacy of single-atom ruthenium anchored on a perovskite material for enhanced PCFC performance.

Main Methods:

• Synthesis of a novel single-atom Ru anchor on BaCe_0.125Fe_0.875O_3-δ (BCF) perovskite using a facile and scalable solid-state approach.
• Theoretical and experimental analyses to characterize the single-atom Ru on BCF structure and its catalytic activity.
• Fabrication and testing of a single PCFC cell utilizing the optimized 2Ru-BCF cathode.

Main Results:

• The single-atom Ru on BCF exhibits a unique 4-coordinate Ru-O-Fe configuration, inducing reverse hydrogen spillover and acting as an active site for P-ORR.
• The optimized 2Ru-BCF cathode achieved a peak power density of 1.78 W cm^-2 at 700 °C in a single PCFC.
• The 2Ru-BCF cathode demonstrated excellent operational stability for over 200 hours.

Conclusions:

• Single-atom engineering on perovskite materials is an effective strategy to enhance P-ORR kinetics and durability in PCFCs.
• The developed Ru-anchored BCF cathode significantly advances the commercial viability of PCFC technology.
• This study provides new insights into catalyst design for efficient electrochemical energy conversion.