Key Takeaways
- Researchers at Tianjin University developed a new photocatalyst that uses sunlight to convert nitrogen from the air into ammonia more efficiently, using a metal-nonmetal co-doping strategy.
- The catalyst, a boron- and cobalt-doped titanium-based metal-organic framework (Ti-MOF), achieved an ammonia production rate of 379.2 µmol g⁻¹ h⁻¹, more than four times higher than the original material.
- The improved catalyst maintained its performance and crystal structure across repeated reaction cycles, demonstrating strong stability.
- The findings were published in the journal Green Chemical Engineering.
- Researchers say the dual-doping strategy could extend to other solar-powered chemical processes, including hydrogen production and carbon dioxide conversion.
Tianjin University Targets Ammonia’s Carbon Problem
Ammonia is essential for fertilizer production and is increasingly viewed as a promising clean energy carrier, but nearly all of it is still made using the century-old Haber-Bosch process, which requires high temperature, high pressure and large amounts of energy. A team at Tianjin University in China has developed a new photocatalyst designed to convert nitrogen from the air into ammonia using sunlight instead, with significantly higher efficiency than earlier versions of the material.
A Dual-Doping Strategy
The Tianjin University researchers modified a titanium-based metal-organic framework by introducing boron and cobalt. Boron helps direct electrons toward the catalyst’s active sites, while cobalt creates an additional pathway for electron transfer; together they form an integrated electron transfer network that lets light-generated electrons move more efficiently and drive the nitrogen-to-ammonia reaction.
The resulting catalyst reached an ammonia production rate of 379.2 micromoles per gram per hour, more than four times higher than the original material, while maintaining its crystal structure and performance across repeated reaction cycles.
“Our work demonstrates that metal-nonmetal co-doping can simultaneously construct both ligand-to-metal and metal-to-metal electron transfer pathways within a single MOF framework, achieving a synergistic effect beyond simple additive contributions,” said Dong Yang, Tianjin University.
“This metal-nonmetal co-doping strategy opens an avenue to designing high-performance MOF-based photocatalysts by engineering electron transfer pathways at the molecular level,” said Zhongyi Jiang, Tianjin University.
Potential Beyond Ammonia
The Tianjin University team believes the dual-doping approach could also improve photocatalysts used for hydrogen production, carbon dioxide conversion and other solar-powered chemical processes. The findings were published in the journal Green Chemical Engineering.
