Atomic Tuning of Metal-Support Interactions for Pathway-Selective CO₂ Photoreduction on TiO₂

Area of Science:

• Catalysis
• Materials Science
• Photochemistry

Background:

• Precise control over multielectron reaction pathways is crucial for selective solar fuel production via photocatalytic CO2 conversion.
• Atomically dispersed metal catalysts on supports offer tunable electronic properties for targeted reactions.

Purpose of the Study:

• To investigate how atomically dispersed Fe and Cu catalysts on TiO2 influence the selectivity of CO2 photoreduction.
• To elucidate the mechanisms behind CO2 adsorption, intermediate stabilization, and C-C coupling facilitated by single-atom catalysts.

Main Methods:

• In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)
• X-ray absorption fine structure (XAFS) analysis
• Density functional theory (DFT) calculations

Main Results:

• Fe and Cu single-atom catalysts on TiO2 direct divergent CO2 reduction pathways, yielding CO (Fe) and CH4/C2H6 (Cu).
• Metal-support interactions modify electronic structures, stabilize key intermediates, and create oxygen vacancies enhancing CO2 adsorption.
• Cu sites promote C-C coupling for multicarbon product formation under mild conditions.
• Optimized catalysts demonstrated significant enhancements in CO (55.7-fold) and CH4 (44.5-fold) yields compared to pristine TiO2.

Conclusions:

• Rational single-atom catalyst design enables precise manipulation of reaction pathways at the atomic scale for selective CO2 reduction.
• This approach provides a unified framework for advancing selective photoredox catalysis in solar fuel production.