Perovskite-support enhanced metal hydride chemical looping ammonia synthesis

Ammonia is increasingly valued as a carbon-free energy carrier, offering a promising solution for hydrogen storage and conversion. However, conventional ammonia production faces challenges due to its energy-intensive nature, catalyst scaling limitations, and difficulty integrating with intermittent renewable energy sources. Chemical looping ammonia production (CLAP) presents a compelling alternative, enabling nitrogen fixation under milder conditions and overcoming traditional catalyst scaling issues. In this study, we demonstrate the integration of a tuneable metal oxide support-based perovskite LBFC (La 0.875 Ba 0.125 Fe 0.875 Co 0.125 O 3-δ ) with a catalysed nickel lithium hydride (LiH–Ni) system. The combined system significantly enhances nitrogen fixation, lowering the apparent activation energy of the nitridation reaction from 47.8 kJ mol −1 to 41.1 kJ mol −1 . Notably, the LBFC/Ni–LiH composite achieved an ammonia production rate of 894 μmol g −1 LiH h −1 at 300 °C and atmospheric pressure. This rate further increased to 2889 μmol g −1 LiH h −1 when the reaction was conducted at 5 bar. These chemical looping ammonia synthesis rates are highly competitive, matching the performance of benchmark for Cs + -Ru (2 wt%)/MgO co-fed catalyst's performance under similar conditions (typically ≈ 560 μmol g −1 h −1 ), and significantly surpasses unpromoted Ru/MgO. • Perovskite-supported LiH–Ni system boosts ammonia synthesis efficiency. • Lower nitridation activation energy achieved with LBFC–LiH–Ni integration. • Ammonia yield hits 969 μmol g −1 h −1 at 5 bar, outperforming benchmark Ru/MgO. • Chemical looping approach enables efficient nitrogen fixation at mild conditions.