Tandem Active Sites in Cu/Mo‐WO₃ Electrocatalysts for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 5, 2025

Abstract Electrocatalytic NO 3 − reduction to NH is a promising technique for both ammonia synthesis and nitrate wastewater treatment. However, this conversion involves tandem processes of H 2 O dissociation hydrogenation, leading inferior Faraday efficiency (FE) yield rate. Herein, catalyst by anchoring atomically dispersed Cu species on Mo‐doped WO (Cu 5 /Mo 0.6 ‐WO ) the RR constructed, which achieves superior FE N 98.6% rate 26.25 mg h −1 cat at −0.7 V (vs RHE) in alkaline media, greatly exceeding performance Mo /WO counterparts. Systematic electrochemical measurement results reveal that promoted activation sites, accompanying accelerated water producing active hydrogens are responsible performance. In situ infrared spectroscopy theoretical calculation further demonstrate sites accelerate , dopant activates adjacent resulting decreased energy barrier * stepwise hydrogenation processes, making thermodynamically favorable. This work demonstrates critical role atomic level enhancing electrocatalytic paving feasible avenue developing high‐performance electrocatalysts.

Language: Английский

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Coupling Nitrate‐to‐Ammonia Conversion and Sulfion Oxidation Reaction Over Hierarchical Porous Spinel MFe₂O₄ (M═Ni, Co, Fe, Mn) in Wastewater

Small, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 7, 2025

The construction of coupled electrolysis systems utilizing renewable energy sources for electrocatalytic nitrate reduction and sulfion oxidation reactions (NO3RR SOR), is considered a promising approach environmental remediation, ammonia production, sulfur recovery. Here, simple chemical dealloying method reported to fabricate hierarchical porous multi-metallic spinel MFe2O4 (M═Ni, Co, Fe, Mn) dual-functional electrocatalysts consisting Mn-doped NiFe2O4/CoFe2O4 heterostructure networks Ni/Co/Mn co-doped Fe3O4 nanosheet networks. excellent NO3RR with high NH3 Faradaic efficiency 95.2% at -0.80 V versus reversible hydrogen electrode (vs RHE) yield rate 608.9 µmol h-1 cm-2 -1.60 vs RHE, impressive SOR performance (100 mA [email protected] achieved MFe2O4. Key intermediates such as *NO, *NH2, are identified in the process by situ Fourier transform infrared spectroscopy (in FTIR). MFe2O4-assembled two-electrode coupling system (NO3RR||SOR) shows an ultra-low cell voltage 1.14 10 cm-2, much lower than NO3RR||OER (oxygen evolution reaction, [email protected] V), simultaneously achieving two expected targets value-added generation recovery, also demonstrating durability 18 h. This work demonstrates great potential ferrite-based catalysts remediation.

Language: Английский

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Efficient Photoelectrocatalytic Synthesis of Ammonia by Superionic Conductor with Mixed Ion/Electron Conduction

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 25, 2025

Photoelectrochemical (PEC) nitrate reduction shows substantial potential for solar-to-ammonia (NH3) conversion. However, low electron density and disordered conduction of conventional catalysts result in limited performance Faraday efficiency. Herein, a FePS2.66Li0.87 superionic conductor (SIC) is developed by introducing lithium ions into van der Waals immobile layered FePS3 catalyst. This crystal framework facilitates high-concentration confinement long-range diffusion at room temperature, transitioning the mechanism from electronic to mixed ionic/electronic. The typical nanofluidic ion transport leads high ionic conductivity 16.4 mS cm-1 temperature enhanced 5 × 10-6 S cm-1. Furthermore, mobile within interlayers enhance interaction between low-lying 3dyz orbitals Fe interacting with 2a2 empty antibonding NO3 -. An excellent PEC ammonia production 134.18 µmol cm-2 h-1 96.95% Faradaic efficiency achieved, corresponding solar-to-NH3 57.13% offers promising pathway toward sustainable production.

Language: Английский

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Hydration‐effect Boosted Active Hydrogen Facilitates Neutral Ammonia Electrosynthesis from Nitrate Reduction

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 8, 2024

Abstract Electrocatalytic nitrate reduction to ammonia (NO 3 RR) in a neutral medium is green and effective strategy for treating pollution meanwhile producing ammonia. However, the insufficient active hydrogen (H * ) on catalyst surface resulting from sluggish Volmer step 2 O → H + OH − ), competitive evolution reaction (HER) caused by coupling severely restrict enhancement of NO RR activity. Herein, hydration‐effect boosted ‐rich facilitating electrosynthesis proposed. The introduction hydration‐effect‐promoting element aluminum into copper‐based forming CuAlO , which adjusts electron density distribution system, significantly promotes generation medium. Moreover, rapid charge transfer at CuO/CuAlO interface facilitates kinetics diffusion. More importantly, Al weakens overly strong adsorption intermediates CuO, thereby accelerating hydrogenation process suppressing HER. Thus, under conditions, reached Faradaic efficiency an yield as high 97.81 ± 1.94% 10.21 0.64 mg h −1 cm −2 −1.0 V versus RHE toward RR.

Language: Английский

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Insights into Electrochemical Nitrate Reduction to Nitrogen on Metal Catalysts for Wastewater Treatment

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: 59(6), P. 3263 - 3275

Published: Jan. 6, 2025

Electrocatalytic nitrate reduction reaction (NO3RR) to harmless nitrogen (N2) presents a viable approach for purifying NO3–-contaminated wastewater, yet most current electrocatalysts predominantly produce ammonium/ammonia (NH4+/NH3) due challenges in facilitating N–N coupling. This study focuses on identifying metal catalysts that preferentially generate N2 and elucidating the mechanistic origins of their high selectivity. Our evaluation 16 commercially available metals reveals only Pb, Sn, In demonstrated substantial selectivity (79.3, 70.0, 57.0%, respectively, under conditions 6 h electrolysis, density 10 mA/cm2, an initial NO3–-N concentration 100 mg/L), while others largely favored NH4+ production. Comprehensive experimental theoretical analyses indicate NH4+-selective (e.g., Co) exhibited water activity enhances •H coverage, thereby promoting hydrogenation NO3– through hydrogen atom transfer mechanism. contrast, N2-selective catalysts, with lower activity, promoted formation N-containing intermediates, which likely undergo dimerization form via proton-coupled electron Enhancing adsorption was beneficial improve by competitively reducing coverage. findings highlight crucial role NO3RR performance offer rational design enhanced

Language: Английский

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FeIr Alloy Optimizes the Trade‐Off Between Nitrate Reduction and Active Hydrogen Generation for Efficient Electro‐Synthesis of Ammonia in Neutral Media

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 10, 2025

Abstract Electrochemically promoted nitrate reduction reaction (NITRR) holds great potential for the “green” synthesis of ammonia (NH 3 ). However, NITRR in neutral media, though close to practical scenario, is often limited by an insufficient supply active hydrogen (*H) due sluggish water cleavage. In this work, it demonstrated that a bimetallic alloy FeIr can optimize trade‐off between and *H formation media. As result, exhibits excellent catalytic performance toward with Faradaic efficiency NH up 97.3% high yield rate 11.67 mg h −1 cm −2 at low working −0.6 V (versus reversible electrode (RHE)), surpassing monometallic catalysts as well majority Fe‐based state‐of‐the‐art. It also found displays remarkable electron rearrangement hetero‐atoms their significant orbital hybridization, which benefits not only but process. Moreover, coupling FeIr‐based methanol oxidation (MOR) results sustainable productions formate combined FE nearly 200% cell‐voltage 2 V. This work thus demonstrates promising strategy designing efficient NITRR.

Language: Английский

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Advances in rare earth catalysts for small molecule electrosynthesis☆

Journal of Rare Earths, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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Highly Stable Perovskite Oxides for Electrocatalytic Acidic NOx− Reduction Streamlining Ammonia Synthesis from Air

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 13, 2024

Electrochemical nitrogen oxide ions reduction reaction (NO

Language: Английский

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Recent Progress in Cobalt‐Based Electrocatalysts for Efficient Electrochemical Nitrate Reduction Reaction

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 9, 2024

Abstract Electrochemical nitrate reduction reaction (NO 3 − RR) provides a sustainable and efficient way to producing ammonia at ambient condition denitrifying wastewater. However, NO RR is still confronted with some barriers present, because of the sluggish kinetics competitive hydrogen evolution (HER). Particularly, it requires highly robust selective electrocatalysts, which steers complex multistep reactions toward process. Among various Co‐based electrocatalysts demonstrate rapid kinetics, steady catalytic performance, suppressive impact on HER for RR, attracting more attention. In this review, focused Cobalt‐based design corresponding strategies are summarized. detail, these can be concisely classified into five categories, including oxides hydroxides, alloys, metal, heteroatom‐doped materials, metal organic frameworks derivatives. Each category extensively discussed, its concepts ideas clearly conveyed through appropriate illustrations figures. Finally, scientific technological challenges as well promising constructing system in future discussed. It expected that review provide valuable insights guidance rational ultimately advancing their applications industrial scenario high current density, stability, energy efficiency.

Language: Английский

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Electrocatalytic Ammonia Oxidation by Pyridyl-Substituted Ferrocenes

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 14, 2025

Ammonia (NH3) is a promising carbon-free fuel when prepared from sustainable resources. First-row transition metal electrocatalysts for ammonia oxidation are an enabling technology energy production. We describe electrocatalytic using robust molecular complexes based on Earth-abundant iron. Electrochemical studies of ferrocenes with covalently attached pyridine arms reveal facile in DMSO (2.4 M NH3) modest overpotentials (η = 770–820 mV) and turnover frequencies (125–560 h–1). Experimental computational indicate that the pendant pyridyl base serves as H-bond acceptor N–H bond transfers proton to following by ferrocenium moiety proton-coupled electron transfer (PCET) step. This generates amidyl (•NH2) radical stabilized via H-bonding pyridinium rapidly dimerizes hydrazine (H2N–NH2), which easily oxidized nitrogen (N2) at glassy carbon working electrode. report identifies general strategy oxidize (B:), thereby activating [B···H-NH2] toward PCET proximal oxidant form [BH···NH2]+/• cations, susceptible dimerization hydrazine.

Language: Английский

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