Emerging Electrochemical Techniques for Probing Site Behavior in Single-Atom Electrocatalysts.

Area of Science:

• Electrocatalysis
• Materials Science
• Analytical Chemistry

Background:

• Single-atom catalysts (SACs) offer high atomic utilization but present challenges in characterizing individual active sites due to complex environments and low metal loadings.
• Conventional ensemble measurements struggle to accurately assess the subnanoscale properties of SACs, hindering fundamental understanding.
• Advanced in situ/operando techniques are crucial for identifying active sites, intermediates, and dynamic behaviors in SACs.

Purpose of the Study:

• To review recent electrochemical probing techniques for identifying and analyzing single-atomic catalytic sites within solid supports.
• To elucidate the principles of molecular probe methods and single-entity electrochemistry for studying SACs.
• To discuss the capabilities, limitations, and future prospects of atomic-resolution electrochemical techniques for energy conversion reactions.

Main Methods:

• Utilizing molecular probe methods to analyze electrocatalytic site behavior.
• Employing in situ surface interrogation scanning electrochemical microscopy (SI-SECM) for high-resolution measurement of active site density and kinetics.
• Applying single-entity electrochemistry for unique electrochemical imaging of single atoms, molecules, and clusters.

Main Results:

• Demonstrated electrochemical probing techniques can effectively identify single-atomic catalytic sites.
• SI-SECM allows precise measurement of active site density and kinetic rates.
• Single-entity electrochemistry provides atomic-level imaging of catalytic performance.

Conclusions:

• Electrochemical techniques with atomic resolution significantly enhance the observation and understanding of surface and interface chemistry in energy conversion.
• Emerging techniques offer powerful capabilities for studying SACs in reactions like oxygen reduction/evolution and hydrogen evolution.
• Continued development of these techniques is vital for advancing fundamental knowledge and technical progress in SACs.