Tuning the Electronic and Steric Interaction at the Atomic Interface for Enhanced Oxygen Evolution

Area of Science:

• Heterogeneous catalysis
• Surface science
• Nanomaterials

Background:

• The activity of heterogeneous catalysts is dictated by their surfaces and interfaces.
• Single-atom catalysts (SACs) provide atomic-level insights but their interfacial mechanisms are not fully understood.
• The applicability of traditional interface concepts to zero-dimensional SACs remains unclear.

Purpose of the Study:

• To investigate the interfacial interactions of single iridium atoms within a cobalt oxyhydroxide (CoOOH) lattice for enhanced oxygen evolution reactions (OER).
• To compare the catalytic mechanisms of confined single atoms versus surface-anchored single atoms.
• To elucidate the role of electronic and steric effects in SACs for OER.

Main Methods:

• Synthesis of iridium single atoms confined within CoOOH lattice.
• Synthesis of iridium single atoms anchored on CoOOH surface.
• Electrochemical characterization to assess oxygen evolution activity.
• Computational analysis to understand electronic structure and interfacial interactions.

Main Results:

• Confining iridium single atoms within CoOOH facilitated efficient electron transfer between Ir and Co, tuning intermediate adsorption for improved OER.
• Surface-anchored iridium atoms showed minimal electronic modification but significant steric effects at the Ir-OH-Co interface.
• Both strategies reduced the energy barrier for oxygen evolution, but through different interfacial mechanisms.

Conclusions:

• The location of single atoms critically influences interfacial interactions and catalytic performance in OER.
• Confined single atoms primarily utilize electronic effects for tuning adsorption, while surface-anchored atoms rely more on steric interactions.
• This work provides a deeper understanding of SACs' interfacial chemistry, guiding future catalyst design.