Engineered "Molecule-Junction" to Transport Photo-Generated Electrons for CO₂ Reduction to Ethane

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Efficient electron transport is crucial for photocatalysis, but achieving targeted transfer remains a challenge.
• Constructing molecular junctions between photocatalysts and active sites can enable precise directional electron transfer.
• Developing efficient photocatalysts for CO2 reduction is vital for sustainable chemical synthesis.

Purpose of the Study:

• To construct a "molecule-junction" using 2-mercaptonicotinic acid (H2L) to connect Ni-doped BiOCl (Ni/BOC) and gold nanoparticles (Au NPs).
• To investigate the role of this junction in facilitating directional electron transfer for CO2 photoreduction.
• To evaluate the performance of the constructed photocatalyst (Ni/BOC-H2L-Au) in converting CO2 into valuable products.

Main Methods:

• Synthesis of Ni-doped BiOCl (Ni/BOC) and its functionalization with 2-mercaptonicotinic acid (H2L) and Au NPs.
• Characterization using X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Fine Structure (XAFS) to confirm the molecular junction.
• Photocatalytic CO2 reduction experiments to assess ethane (C2H6) yield and selectivity.

Main Results:

• Successful construction of a "molecule-junction" verified by the presence of Bi─S and Au─S bonds.
• The Ni/BOC-H2L-Au photocatalyst demonstrated exceptional performance in CO2 photoreduction, yielding 155.4 µmol g⁻¹ h⁻¹ of ethane (C2H6) with 85.8% selectivity.
• The junction facilitated a directional electron transfer pathway (Ni/BOC→H2L→Au NPs), enhancing charge separation and electron accumulation.

Conclusions:

• The "molecule-junction" strategy effectively promotes targeted electron transfer, significantly boosting CO2 photoreduction efficiency.
• The Ni/BOC-H2L-Au system represents a highly efficient photocatalyst for producing valuable C2+ products from CO2.
• This work offers a promising approach for designing advanced photocatalysts for high-value chemical synthesis.