Insights into the Proton-Coupled Electron Transfer Mechanism in Fuel Cells

Area of Science:

• Energy science and electrochemistry
• Materials science for energy conversion

Background:

• Proton-coupled electron transfer (PCET) is crucial for energy systems and fuel cell (FC) electrocatalysis.
• Understanding PCET mechanisms is key to improving low-temperature protonic ceramic fuel cells (PCFCs).

Purpose of the Study:

• To investigate the PCET mechanism in low-temperature PCFCs.
• To evaluate PCET's role in catalyzing hydrogen oxidation and oxygen reduction reactions.

Main Methods:

• Experimental investigation of PCET in PCFCs operating at 300-500 °C.
• Analysis of electrochemical performance, charge-transfer resistance, and activation energy.
• Proton injection experiments to assess PCET robustness via relaxation time changes.

Main Results:

• PCET significantly enhances electrocatalytic activity in PCFCs.
• Charge-transfer resistance is reduced by 1-2 orders of magnitude with PCET.
• Activation energy is reduced to 0.31 eV, indicating efficient energy barrier overcoming.
• Proton injection confirmed the robustness of the PCET mechanism.

Conclusions:

• PCET is critical for optimizing electrocatalytic performance in PCFCs.
• PCET mitigates polarization losses and accelerates reaction kinetics.
• This research highlights PCET's importance in advancing fuel cell technology.