Ru-doped SrXO_y/CNT as microwave-responsive catalysts for low-temperature and atmospheric pressure ammonia synthesis

The strong N[tbnd]N bond, notoriously difficult to dissociate, has long posed a significant challenge to ammonia synthesis under mild conditions, typically requiring high temperatures and pressures. Here, Ru-supported Sr-based perovskite/CNT core/shell composites were developed as microwave-responsive catalysts for ammonia synthesis. Leveraging their exceptional microwave responsiveness, Ru/SrCeO₃/CNT achieved an NH₃ production rate of 1.04 mmol·(g·h)⁻¹ at 300 °C and 0.1 MPa, with no deactivation observed after 72 h. The energy consumption reached 0.10 MJ·(mol·g)⁻¹ at 30 W much lower than the recent research on microwave ammonia synthesis. The core/shell architecture facilitated in-situ heat generation from the CNT core, enhancing interfacial reactions on Ru nanoparticles. Furthermore, XPS and H₂-TPR analyses revealed that oxygen vacancies and strong interfacial interactions in the SrCeO₃ support boosted the electron-donating capacity of Ru active sites, promoting N[tbnd]N bond cleavage. This work offers a scalable, energy-efficient strategy for sustainable ammonia production.