Interface-Engineering-Induced C-C Coupling for C₂H₄ Photosynthesis from Atmospheric-Concentration CO₂ Reduction

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Photoreduction of carbon dioxide (CO2) to valuable fuels like ethylene (C2H4) is a promising sustainable energy strategy.
• A major hurdle in CO2 photoreduction is the inefficient carbon-carbon (C-C) coupling step, limiting ethylene production.
• Existing methods often require harsh conditions or struggle with low yields and selectivity.

Purpose of the Study:

• To design and synthesize novel semiconductor-based catalysts for efficient CO2 photoreduction to ethylene.
• To investigate the mechanism of C-C coupling facilitated by heteroatom sites at the catalyst interface.
• To achieve high-rate ethylene production from ambient concentration CO2 in pure water under mild conditions.

Main Methods:

• Fabrication of palladium (Pd) nanoclusters anchored on zinc oxide (ZnO) nanosheets.
• Characterization using X-ray photoelectron spectroscopy (XPS) and high-angle annular dark-field (HAADF) imaging.
• In situ and quasi in situ spectroscopic techniques (FTIR, XPS) to probe reaction intermediates and active sites.
• Density functional theoretical (DFT) calculations to determine reaction energy barriers.

Main Results:

• Successfully synthesized Pd nanoclusters on ZnO nanosheets (Pd-ZnO) with confirmed active sites.
• Demonstrated efficient C-C coupling for ethylene (C2H4) formation via CO2 photoreduction.
• Achieved an ethylene formation rate of 1.03 μmol g⁻¹ h⁻¹ using atmospheric CO2 in pure water.
• DFT calculations revealed a low energy barrier (0.998 eV) for the key C-C coupling step.

Conclusions:

• Pd-ZnO nanosheets effectively steer C-C coupling through interfacial heteroatom sites, enabling efficient ethylene production.
• The developed catalyst system facilitates the conversion of ambient CO2 into valuable C2H4 fuel under mild, aqueous conditions.
• This work presents a significant advancement in CO2 photoreduction catalysis, paving the way for sustainable fuel synthesis.