Amorphous Bismuth-Tin Oxide Nanosheets with Optimized C-N Coupling for Efficient Urea Synthesis

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science
• Sustainable Chemistry

Background:

• Electrochemical conversion of carbon dioxide (CO2) and nitrogen compounds using renewable energy offers a sustainable pathway to valuable chemicals.
• Current methods primarily focus on independent CO2 or nitrate reduction, with limited efficiency for complex C-N compound synthesis due to catalyst limitations.
• Developing effective catalysts is crucial for advancing the electrochemical synthesis of high-value C-N compounds.

Purpose of the Study:

• To develop novel catalysts for efficient and selective electrochemical synthesis of urea from CO2 and nitrogen-containing feedstocks.
• To investigate a new C-N coupling pathway facilitated by enhanced CO2 adsorption and activation.
• To improve the energy efficiency and selectivity of urea production.

Main Methods:

• Synthesis of amorphous bismuth-tin oxide nanosheets as electrocatalysts.
• Electrochemical reduction experiments to evaluate urea production efficiency and selectivity.
• Analysis of CO2 adsorption, activation, and reaction intermediates using computational insights.
• Optimization of catalyst performance at a potential of -0.4 V vs RHE.

Main Results:

• Amorphous bismuth-tin oxide nanosheets demonstrated high catalytic activity and selectivity for urea production.
• A novel C-N coupling pathway based on CO2 activation, rather than CO, was realized.
• Achieved an outstanding Faraday efficiency of 78.36% for urea production.
• Enhanced nitrogen and carbon selectivity for urea formation to 90.41% and 95.39%, respectively.

Conclusions:

• Amorphous bismuth-tin oxide nanosheets are effective catalysts for efficient electrochemical urea synthesis.
• The study provides a new C-N coupling mechanism and highlights the importance of catalyst design for CO2 utilization.
• These findings offer valuable insights for developing advanced catalysts for synthesizing high-value C-N compounds from CO2.