Electrochemical nitrate reduction to ammonia (NRA) represents a promising strategy for environmental remediation and sustainable nitrogen cycling, particularly when powered by renewable energy sources. The development of efficient catalysts capable of achieving high Faradaic efficiency and selectivity under mild neutral conditions remains a critical challenge. In this work, we report the design and synthesis of a metasequoia-like nanocrystalline iron-doped copper (CuFe) catalyst that exhibits exceptional performance in electrocatalytic NRA within neutral electrolytes. The CuFe catalyst, with approximately 2% Fe doping, demonstrates a current density of 55.6 mA cm⁻² at an applied potential of −0.7 V vs. reversible hydrogen electrode (RHE), which is 2.1 times higher than that of pure Cu. Moreover, it achieves a Faradaic efficiency of up to 94.5% and a selectivity of 86.8% toward ammonia production—remarkable improvements over conventional Cu-based systems.
The catalyst was fabricated via electrodeposition, resulting in a unique hierarchical metasequoia-like morphology confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). High-resolution TEM revealed lattice spacing of 0.210 nm corresponding to the Cu(111) plane, while elemental mapping showed uniform distribution of Cu and Fe throughout the nanostructure. X-ray diffraction (XRD) patterns indicated retention of the face-centered cubic structure of Cu without formation of secondary phases, suggesting successful atomic-level doping rather than phase segregation. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Fe and demonstrated a negative shift in Cu 2p binding energies, indicating electron redistribution from Fe incorporation into the Cu 3d band.
Density functional theory (DFT) calculations further revealed that Fe doping shifts the d-band center of Cu to a deeper energy level (−2.47 eV vs. −2.41 eV for pure Cu), which optimizes the adsorption energies of key reaction intermediates (*NO₃⁻, *NO₂, *NO, *N, *NH, *NH₂, *NH₃). This favorable electronic tuning enhances the kinetics of nitrate reduction and suppresses undesired side reactions such as hydrogen evolution or partial reduction to nitrite. Electrochemical tests in a neutral 0.1 M K₂SO₄ solution containing 2 mM KNO₃ showed that the Cu₄₉Fe₁ variant delivered the highest half-wave potential (E₁/₂ = −0.36 V vs. RHE) and exhibited an eight-electron transfer process consistent with complete nitrate-to-ammonia conversion.TNFSF15 Antibody Autophagy
A H-type cell equipped with a Nafion 117 membrane enabled precise quantification of NH₃ yield and selectivity.MCM6 Antibody Autophagy At −0.PMID:34187261 74 V vs. RHE, Cu₄₉Fe₁ achieved a nitrate conversion rate of 96.9%, ammonia yield of 0.23 mmol h⁻¹ cm⁻², and selectivity of 86.8%. These values significantly outperformed plain Cu, Cu₉₉Fe₁, and Cu₁₉Fe₁ samples. Long-term stability tests demonstrated no decay in activity after four consecutive runs, and post-test SEM and XRD analyses confirmed structural integrity.
This study highlights the power of rational heteroatom doping in tuning the electronic structure of Cu-based catalysts for advanced electrochemical applications. The combination of experimental characterization and theoretical modeling provides clear insight into the mechanism behind enhanced NRA performance. The proposed CuFe catalyst offers a robust, scalable, and environmentally friendly pathway for converting nitrate pollutants into valuable ammonia under neutral conditions, advancing the vision of a closed nitrogen cycle.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com