Structural evolution and strain generation of derived-Cu catalysts during CO₂ electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Copper catalysts are key for electrochemical CO2 reduction (CO2RR) with high C2+ selectivity.
• The precise mechanisms and precursor effects influencing this selectivity remain unclear.

Purpose of the Study:

• To investigate the structural and compositional evolution of copper precursors during CO2RR.
• To understand the origin of high C2+ selectivity in copper-based CO2RR catalysts.

Main Methods:

• Operando X-ray diffraction and operando Raman spectroscopy were employed.
• Three different copper precursors were studied under electrochemical CO2 reduction conditions.
• Theoretical calculations were used to support experimental findings.

Main Results:

• All precursors fully reduced to Cu(0) with similar grain sizes (~11 nm); oxidized Cu species were not active.
• Cu derived from Cu(OH)2 and Cu2(OH)2CO3 precursors exhibited significant tensile strain (0.43%–0.55%).
• CuO-derived Cu showed no significant lattice strain.

Conclusions:

• High CO2RR performance is linked to small grain size and tensile lattice strain in derived copper catalysts.
• Tensile strain in the copper lattice promotes CO2RR, as supported by theoretical calculations.
• In situ electroreduction of precursors is crucial for achieving optimal catalyst properties and performance.