Charge-Directed Photothermal Methane Dry Reforming Enabled by Interfacial TiO_x Nanodomains

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Photothermal dry reforming of methane (DRM) offers a solar-driven pathway for upgrading methane (CH ₄ ) and carbon dioxide (CO ₂ ).
• Catalyst efficiency and durability in photothermal DRM are often limited by carbon deposition and unclear photochemical mechanisms.
• Developing robust catalysts is crucial for advancing solar fuel technologies.

Purpose of the Study:

• To design and investigate a charge-directed photothermal DRM catalyst for enhanced efficiency and durability.
• To elucidate the role of interfacial TiO _x domains in coupling photocarrier flow and oxygen chemistry.
• To mitigate carbon deposition and improve syngas production rates.

Main Methods:

• Fabrication of a catalyst comprising Rh nanoparticles supported on TiO _x -functionalized TiC.
• Utilizing metallic TiC to generate and direct charge carriers (electrons and holes) upon illumination.
• Analyzing the interfacial chemistry involving TiO _x surface oxygens and oxygen vacancies.

Main Results:

• The catalyst demonstrated selective lowering of the activation barrier for *OCH ₃ formation, suppressing over-dehydrogenation and carbon deposition.
• A regenerative photothermal Mars-van Krevelen cycle was established via CO ₂ activation at TiO _x oxygen vacancies.
• Achieved high syngas production rates (CO: 17.5 mol g _Rh ^-1 h ^-1 , H ₂ : 10.5 mol g _Rh ^-1 h ^-1 ) with a light-to-chemical energy efficiency of 29% and stable operation (>100 h).

Conclusions:

• Amorphous TiO _x interfaces are critical for charge-directed photothermal DRM, enabling coking resistance.
• The developed catalyst design provides a pathway for creating highly efficient and durable reforming catalysts.
• This work advances the understanding of interfacial phenomena in photothermal catalysis for renewable energy applications.