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High Resolution Image Download MS PowerPoint Slide In the pursuit of sustainable ammonia synthesis and nitrate remediation, electrochemical nitrate reduction to ammonia (eNO 3 RR) emerges as a promising alternative to the carbon-intensive Haber–Bosch process, which emits 1.6–2.0 tons of CO 2 per ton of ammonia. Powered by renewable energy, the eNO 3 RR offers reduced emissions and energy consumption but faces challenges in catalytic activity and product selectivity due to its complex mechanism. To address these issues, CeFeO 3 supported CeO 2 composites were synthesized via a microwave polyol method with varying Ce:Fe atomic ratios and comprehensively characterized. Electrochemical analysis revealed that pure CeO 2 achieved a high ammonia yield rate of 4040.5 ± 262.5 μg h –1 cm –2 but with a lower Faradaic efficiency (FE) of 52.8 ± 2.8% at −0.45 V RHE in 0.1 M KOH with 0.1 M NO 3 – . Introducing CeFeO 3 into CeO 2 enhanced FE significantly, reaching a maximum of 80.1 ± 3.3% with an ammonia yield rate of 3223.9 ± 168.3 μg h –1 cm –2 . Parasitic hydrogen evolution accounted for only 4.9 ± 0.9% FE, while hydroxylamine and nitrite, key intermediates, contributed 8.3 ± 1.2% and 6.7 ± 0.9%, respectively. Stability was demonstrated over 25 one hour cycles (25 h total) at −0.45 V RHE with electrolyte replacement. The intrinsic perovskite structure of CeFeO 3, facilitating electron exchange via oxygen vacancies, underpinned the improved performance. H 2 –NO 3 – fuel cell studies showed 74.6% thermodynamic efficiency at a current density of 29.7 mA cm –2 at 0.46 V. This study underscores CeFeO 3 /CeO 2 composites’ potential for sustainable ammonia production and environmental remediation.
Ebenezer et al. (Thu,) studied this question.