Distortion-Induced Interfacial Charge Transfer at Single Cobalt Atom Secured on Ordered Intermetallic Surface...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for renewable energy technologies.
• Intermetallic compounds offer unique electronic properties that can be leveraged for catalysis.

Purpose of the Study:

• To synthesize and characterize a novel catalyst comprising atomic cobalt incorporated into a Pd2Ge intermetallic lattice for OER.
• To elucidate the operando formation and role of a cobalt oxide (CoO) layer on the Pd2Ge core in enhancing catalytic performance.

Main Methods:

• Synthesis of Co-substituted Pd2Ge and operando characterization using High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy.
• Electrochemical evaluation of OER activity and durability, including selective removal of the CoO layer.
• In situ spectroscopic techniques (XANES, EXAFS, Raman) and Density functional theory (DFT) calculations to understand reaction mechanisms and electronic structure.

Main Results:

• Atomic cobalt incorporation into Pd2Ge facilitates the operando generation of a CoO surface layer, forming the Co1-CoO-Pd2Ge catalyst.
• The CoO layer transforms to CoOOH under OER conditions, with enhanced charge transfer facilitated by the Pd2Ge core.
• DFT calculations and experimental data confirm that the Pd2Ge lattice induces spin density and improves OER activity and durability.

Conclusions:

• The intermetallic Pd2Ge core plays a vital role in enhancing charge transfer, generating spin density, and improving the electrochemical durability and stability of the CoOOH overlayer.
• The synthesized Co1-CoO-Pd2Ge catalyst demonstrates promising performance for the oxygen evolution reaction.