Boosting Activity and Selectivity of CO₂ Electroreduction by Pre-Hydridizing Pd Nanocubes

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2 RR) to syngas offers a sustainable route for CO2 mitigation and chemical production.
• Palladium (Pd) is a candidate electrocatalyst, forming palladium hydride (PdH) under reaction conditions, but the effect of pre-hydridization is unexplored.

Purpose of the Study:

• To investigate the impact of pre-hydridization on palladium nanocubes for CO2 RR.
• To explore the combined effects of pre-hydridization and nanocube size on catalytic performance.

Main Methods:

• Synthesis of pre-hydridized palladium nanocubes on carbon black (PdH0.40 NCs/C).
• In situ X-ray absorption spectroscopy to analyze phase transformation.
• Density functional theory (DFT) calculations to study reaction intermediates.
• Evaluation of CO2 RR performance and size-dependent effects.

Main Results:

• PdH0.40 NCs/C exhibited enhanced CO2 RR performance compared to Pd nanocubes (Pd NCs/C).
• In situ XAS revealed less cathodic phase transformation in pre-hydridized catalysts.
• DFT calculations indicated altered binding energies of intermediates on PdH0.40.
• Smaller nanocube sizes demonstrated higher activity due to increased edge and corner sites.

Conclusions:

• Pre-hydridization of palladium nanocubes significantly improves CO2 RR activity and selectivity.
• The combination of pre-hydridization and reduced nanocube size offers a synergistic approach for efficient CO2 conversion to syngas.