Defective nanomaterials for electrocatalysis oxygen reduction reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen reduction reaction (ORR) is crucial for fuel cells but suffers from sluggish kinetics due to challenges in O2 adsorption, O-O bond cleavage, and intermediate desorption.
• Highly active and stable electrocatalysts are essential for improving fuel cell performance and commercialization.
• Defects in catalysts significantly influence electronic and geometric structures, offering a pathway to enhance catalytic performance by optimizing adsorption energies.

Purpose of the Study:

• To review and summarize the role of defective electrocatalysts, including noble and non-noble metals, in advancing the ORR.
• To clarify the structure-activity relationships between defect engineering and catalytic performance.
• To provide guidance for the rational design of efficient and robust ORR catalysts for proton-exchange membrane fuel cells (PEMFCs).

Main Methods:

• Review of experimental results and theoretical calculations concerning defective electrocatalysts for ORR.
• Analysis of the impact of defect types, contents, and locations on catalytic performance.
• Investigation of the catalytic mechanisms of defective nanomaterials.

Main Results:

• Defect engineering optimizes substrate and intermediate adsorption energies, enhancing ORR catalytic activity.
• Structure-activity relationships between defect engineering and ORR performance have been clarified.
• Understanding defect mechanisms provides a basis for designing improved ORR catalysts.

Conclusions:

• Defect engineering is a promising strategy to overcome the sluggish kinetics of the ORR.
• Further research is needed to fully understand the nuanced effects of different defect characteristics.
• This review guides the rational design of next-generation ORR electrocatalysts for PEMFCs.