Interface Engineered V-Zn Hybrids: Electrocatalytic and Photocatalytic CO₂ Reductions

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Vanadium-Zinc (V-Zn) hybrids are promising catalysts for environmental and energy applications.
• Electrocatalytic CO2 reduction (EC CO2 RR) is crucial for sustainable energy conversion.
• Developing efficient and selective catalysts for CO2 valorization remains a significant challenge.

Purpose of the Study:

• To prepare and characterize V-Zn hybrid electrodes for electrocatalytic CO2 reduction.
• To investigate the influence of preparation methods, electrolytes, thermal treatment, and photoirradiation on EC CO2 RR performance.
• To explore the potential of V-Zn hybrids in both electrocatalytic and photocatalytic CO2 reduction.

Main Methods:

• V-Zn hybrid electrodes were fabricated using hydrothermal and sputter-deposition techniques on Zn foil.
• Electrocatalytic CO2 reduction was performed under various applied potentials and electrolyte conditions.
• Products were analyzed using gas chromatography and nuclear magnetic resonance spectroscopy.
• Photocatalytic CO2 reduction was also investigated.

Main Results:

• Hydrothermal V-Zn electrodes primarily produced syngas (CO and H2) with tunable ratios.
• Minor products included methane, ethylene, and ethane, with formate observed at 2% Faradaic efficiency.
• Optimal EC CO2 RR efficiency for CO, methane, and formate was achieved in 0.2 M KHCO3.
• Photoirradiation and Nafion treatment enhanced CO and formate production.
• Thermal treatment significantly boosted formate and methane yields.
• Photocatalytic reduction yielded methanol, CO, methane, ethylene, ethane, and notably, long-chain hydrocarbons via Fisher-Tropsch synthesis.

Conclusions:

• V-Zn hybrid electrodes demonstrate tunable electrocatalytic CO2 reduction capabilities.
• Electrolyte choice, thermal treatment, and photoirradiation are key factors in optimizing product selectivity and yield.
• The observation of long-chain hydrocarbons via Fisher-Tropsch synthesis in photocatalytic CO2 reduction is a novel finding.
• These V-Zn hybrid materials show significant potential for energy and environmental applications in CO2 conversion.