Efficient urea electrosynthesis from CO₂ and nitrate on amorphous TiS₂.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrosynthesis of urea via co-electrolysis of carbon dioxide and nitrate (EUCN) presents a sustainable method for urea production.
• Developing efficient and selective catalysts is crucial for advancing EUCN technology.

Purpose of the Study:

• To investigate amorphous titanium disulfide (a-TiS2) with sulfur vacancies (Sv) as a catalyst for EUCN.
• To understand the catalytic mechanism and optimize urea synthesis conditions.

Main Methods:

• Electrochemical synthesis and characterization of a-TiS2.
• Performance evaluation in a flow electrolyzer.
• In situ spectroscopic measurements and theoretical computations.

Main Results:

• a-TiS2 achieved a maximum urea Faradaic efficiency of 34.5% and a yield rate of 30.6 mmol h-1 gcat-1 at -0.7 V RHE.
• The catalyst significantly outperformed crystalline TiS2 and other reported EUCN catalysts.
• Synergistic catalysis involving Ti sites and Ti-Sv sites promoted key reaction intermediates and suppressed side reactions.

Conclusions:

• Amorphous TiS2 with rich sulfur vacancies is a highly effective and robust catalyst for EUCN.
• The study elucidates the catalytic mechanism, highlighting the role of sulfur vacancies in enhancing urea selectivity.
• This work provides a promising pathway for efficient and selective urea electrosynthesis.