Recent developments and prospects for engineering first-row transition metal-based catalysts for electrocatalytic NO_x⁻ reduction to ammonia

Abstract

The immense interest in the electrocatalytic reduction of nitrate (NO3-)/nitrite (NO2-) to ammonia has been driven by promising prospects as an eco-friendly and energy-efficient approach for wastewater treatment and ammonia...

Effects of Ionic Interferents on Electrocatalytic Nitrate Reduction: Mechanistic Insight

“…Catalytic materials influence the end-product selectivity and performance of the overall reaction. − Recent emphasis consistently revolves around the development of electrocatalysts with optimal performance, including noble and transition metals, metal-based materials, and non-metals. ,,− Pt, Pd, Ru, and Au are typically applied noble metals, − while Fe, Co, Ni, and Cu are the alluring transition metals. − Specifically, Cu with highly occupied d orbitals is recognized for its suitability in accelerating the rate-determining step (RDS), i.e., NO 3 – to NO 2 – , as a result of its closely matched d-orbital energy level with the high-energy lowest unoccupied molecular orbital (LUMO) π* orbital of NO 3 – . − Metal-based catalysts are often in the form of alloys, oxides, phosphides, sulfides, and hydroxides. Multi-component metal catalysts, such as alloys introduce hetero units, which optimize the electronic structure of the host metal, providing unique catalytic activity via their synergistic multi-level coupling effects. − Carbon-based materials, such as carbon fiber, carbon black, N-doped carbon, graphite, and graphene-based materials are widely studied non-metal catalysts. − A detailed summary on cathode material designs for eNO 3 RR can be referred to in previous reviews. ,, …”

ZnFe2O4 nanosheet array: a highly efficient electrocatalyst for ambient ammonia production via nitrite reduction

“…21,22 Recent research has pointed to the activity of Fe and its hybrids in the eNO 2 − RR. 23–27 On the other hand, Fe 3 O 4 has garnered favor in the field of electrocatalysis for its ease of synthesis and excellent electrical conductivity, 28–32 making it a promising candidate for eNO 2 − RR applications. Nevertheless, it's worth noting that Fe 3 O 4 faces a challenge in terms of limited adsorption capacity, and thus, further enhancements are required.…”

High-efficiency ammonia synthesis via electrochemical nitrate reduction over Co3O4 nanoarrays by B doping

“…9 In contrast, nitrate (NO 3 − ) exhibits a lower NO bond energy (204 kJ mol −1 ) and increased aqueous solubility, making it a prospective nitrogen reservoir for NH 3 synthesis via electrochemical reduction. 10–17 Moreover, the abundant presence of NO 3 − in sewage imparts detrimental effects on both the environment and human health. 18 Consequently, the electrochemical nitrate reduction reaction (NO 3 − RR) not only facilitates the production of ambient NH 3 , but also plays a crucial role in mitigating nitrate pollution, effectuating the “waste-to-wealth”.…”