Electrocatalytic Hydrogenation Boosts Reduction of Nitrate to Ammonia over Single-Atom Cu with Cu(I)-N₃C₁ Sites

2022/09/29 by Yinghao Xue, Qihui Yu, Ma Qian +5 · 2 citations
Chemical Engineering · Computer Science · Energy · #Advanced Photocatalysis Techniques #Ammonia Synthesis and Nitrogen Reduction #Caching and Content Delivery

paper · doi:10.1021/acs.est.2c04456

openalex publication_date 2022/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31

Abstract

The conversion of nitrate to ammonia can serve two important functions: mitigating nitrate pollution and offering a low energy intensity pathway for ammonia synthesis. Conventional ammonia synthesis from electrocatalytic nitrate reduction reactions (NO 3 RR) is often impeded by incomplete nitrate conversion, sluggish kinetics, and the competition of hydrogen evolution reactions. Herein, atomic Cu sites anchored on micro-/mesoporous nitrogen-doped carbon (Cu MNC) with fine-tuned hydrophilicity, micro-/mesoporous channels, and abundant Cu(I) sites were synthesized for selective nitrate reduction to ammonia, achieving ambient temperature and pressure hydrogenation of nitrate. Laboratory experiments demonstrated that the catalyst has an ammonia yield rate per active site of 5466 mmol g Cu –1 h –1 and transformed 94.8% nitrate in wastewater containing 100 mg-N L –1 to near drinking water standard (MCL of 5 mg-N L –1 ) at −0.64 V vs RHE. Extended X-ray absorption fine structure (EXAFS) and theoretical calculations showed that the coordination environment of Cu(I) sites (Cu(I)-N 3 C 1 ) localizes the charge around the central Cu atoms and adsorbs *NO 3 and *H onto neighboring Cu and C sites with balanced adsorption energy. The Cu(I)-N 3 C 1 moieties reduce the activation energy of rate-limiting steps (*HNO 3 → *NO 2, *NH 2 → *NH 3 ) compared with conventional Cu(II)-N 4 and lead to a thermodynamically favorable process to NH 3 . The as-prepared electrocatalytic cell can run continuously for 84 h (14 cycles) and produce 21.7 mg NH 3 with only 5.64 × 10 –3 kWh energy consumption, suitable for decentralized nitrate removal and ammonia synthesis from nitrate-containing wastewater.

Citations

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• Ammonia and Nitric Acid Demands for Fertilizer Use in 2050
• Theoretical Insights into Superior Nitrate Reduction to Ammonia Performance of Copper Catalysts
• Electrocatalytic nitrate reduction to ammonia on defective Au1Cu (111) single-atom alloys
• Efficient conversion of low-concentration nitrate sources into ammonia on a Ru-dispersed Cu nanowire electrocatalyst
• Potential-Driven Restructuring of Cu Single Atoms to Nanoparticles for Boosting the Electrochemical Reduction of Nitrate to Ammonia
• Simulation of 6 pulse GTO thyristor converter and harmonics analysis

Cited by

• Breaking Local Charge Symmetry of Iron Single Atoms for Efficient Electrocatalytic Nitrate Reduction to Ammonia
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Related

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