Topological Catalyst Boosts Ammonia Synthesis
Ammonia is a vital ingredient in fertilizers, refrigerants, cleaners, and many other industrial products. The conventional process for synthesizing it from nitrogen and hydrogen is energy intensive and environmentally harmful. An electrochemical alternative for producing ammonia, known as the nitric oxide reduction reaction (NORR), needs less energy and offers a more sustainable pathway. But the process still suffers in performance and efficiency. Xinyan Zhang and his colleagues at Hebei University of Technology in China now identify a material whose topological surface states make it a potent catalyst of NORR [1]. Their work offers a promising pathway toward sustainable ammonia production.
Metal catalysts speed up chemical reactions by lowering their activation energy, often by providing a surface on which the reactants interact. Topological semimetals—defined by electronic bands that are protected by symmetry—have recently drawn attention as possible catalysts. Their unique topological surface states, which provide high surface electron density and enhanced carrier mobility, make them suitable for boosting reactions. Zhang and colleagues thought that one such semimetal, CaAgAs, might be suited to NORR.
Using first-principles calculations, the researchers systematically investigated the ability of CaAgAs to catalyze the reduction of nitric oxide. They concluded that CaAgAs could reduce the energy required for a critical step by half compared to conventional copper-based catalysts. The researchers also established a linear relationship between a material’s surface density of states and its catalytic activity. Together, the findings support CaAgAs as a promising catalyst for ammonia synthesis and suggest that other topological semimetals might serve as novel catalysts.
–Rachel Berkowitz
Rachel Berkowitz is a Corresponding Editor for Physics Magazine based in Vancouver, Canada.
References
- X. Zhang et al., “Efficient ammonia synthesis from nitric oxide using the topological nodal-line semimetal CaAgAs,” Phys. Rev. Appl. 25, 044023 (2026).