RT journal article
T1 Single-Atom Catalysts for Low-Temperature Thermocatalytic Ammonia Synthesis
A1 Arroyo Caire, Javier
A1 Abelleira Pereira, José María
A1 Serrano Ruiz, Carlos
A2 Ingeniería Química y Tecnología de Alimentos
K1 ammonia synthesis
K1 mild conditions
K1 nitrogen activation
K1 Ruthenium
K1 single-atom catalysts
K1 thermocatalysis
AB Ammonia is indispensable to the fertilizer and chemical industries, yet its manufacture still relies predominantly on the energy-intensive Haber–Bosch process operated at 400–500 °C and 150–250 bar, with a substantial carbon footprint. Single-atom catalysts (SACs) and sub-nanometric clusters have recently emerged as promising alternatives for thermocatalytic ammonia synthesis under milder conditions because they maximize metal utilization and enable precise control of the active site environment. This review first summarizes how the transition from conventional Fe and Ru nanoparticles to isolated or few-atom sites fundamentally alters the kinetic landscape, favoring associative N2 activation pathways that lower apparent activation energies and alleviate H2 poisoning. We then discuss Ru-based SACs and SAAs supported on zeolites, carbons, ceria, and MXenes, highlighting how strong metal–support and promoter interactions, tandem single-atom/nanoparticle motifs, and alloying strategies tune N2 and H2 binding to deliver high NH3 productivities at 200–400 °C and ≤30 bar. In parallel, we review emerging non-noble systems based on Fe and Co, including high-loading Fe–N4 sites prepared via MOF-derived post-metal-replacement routes and Co single atoms or Co2 clusters on N-doped carbons, which already rival or surpass Ru benchmarks under similar conditions. Collectively, these studies show that tailoring the number of atom metal sites, coordination, and support polarity around isolated metal sites provides a useful tool to mitigate some aspects of volcano and scaling-relation limitations, indicating that SACs could contribute to low-temperature ammonia synthesis when combined with appropriate process design.
PB Multidisciplinary Digital Publishing Institute (MDPI)
SN 1420-3049
YR 2026
FD 2026-04-17
LK http://hdl.handle.net/10498/40427
UL http://hdl.handle.net/10498/40427
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 08-nov-2026