Designing Efficient Nitrate Reduction Electrocatalysts by Identifying and Optimizing Active Sites of Co-Based Spinels

2023/12/29 by Qi Hu, Shuai Qi, Qihua Huo +9 · 2 citations
Chemical Engineering · Computer Science · Energy · #Advanced Photocatalysis Techniques #Ammonia Synthesis and Nitrogen Reduction #Caching and Content Delivery

paper · doi:10.1021/jacs.3c06904

openalex publication_date 2023/12/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/26

Abstract

Cobalt-based spinel oxides (i.e., Co 3 O 4 ) are emerging as low-cost and selective electrocatalysts for the electrochemical nitrate reduction reaction (NO 3 – RR) to ammonia (NH 3 ), although their activity is still unsatisfactory and the genuine active site is unclear. Here, we discover that the NO 3 – RR activity of Co 3 O 4 is highly dependent on the geometric location of the Co site, and the NO 3 – RR prefers to occur at octahedral Co (Co Oh ) rather than tetrahedral Co (Co Td ) sites. Moreover, Co Oh O 6 is electrochemically transformed to Co Oh O 5 along with the formation of O vacancies (O v ) during the process of NO 3 – RR. Both experimental and theoretic results reveal that in situ generated Co Oh O 5 –O v configuration is the genuine active site for the NO 3 – RR. To further enhance the activity of Co Oh sites, we replace inert Co Td with different contents of Cu 2+ cations, and a volcano-shape correlation between NO 3 – RR activity and electronic structures of Co Oh is observed. Impressively, in 1.0 M KOH, (Cu 0.6 Co 0.4 )Co 2 O 4 with optimized Co Oh sites achieves a maximum NH 3 Faradaic efficiency of 96.5% with an ultrahigh NH 3 rate of 1.09 mmol h –1 cm –2 at −0.45 V vs reversible hydrogen electrode, outperforming most of other reported nonprecious metal-based electrocatalysts. Clearly, this work paves new pathways for boosting the NO 3 – RR activity of Co-based spinels by tuning local electronic structures of Co Oh sites.

Citations

• Unveiling the Activity Origin of a Copper‐based Electrocatalyst for Selective Nitrate Reduction to Ammonia
• The role of in situ generated morphological motifs and Cu(i) species in C2+ product selectivity during CO2 pulsed electroreduction
• Efficient Ammonia Electrosynthesis from Nitrate on Strained Ruthenium Nanoclusters
• Operando Identification of the Dynamic Behavior of Oxygen Vacancy-Rich Co3O4 for Oxygen Evolution Reaction
• Electrochemical reduction of nitrate to ammonia via direct eight-electron transfer using a copper–molecular solid catalyst
• Increasing stability, efficiency, and fundamental understanding of lithium-mediated electrochemical nitrogen reduction
• Electrocatalytic Nitrate Reduction for Sustainable Ammonia Production
• Can sustainable ammonia synthesis pathways compete with fossil-fuel based Haber–Bosch processes?
• Electrochemical ammonia synthesis via nitrate reduction on Fe single atom catalyst
• Electrocatalytic Reduction of Nitrate to Ammonia on Low-Cost Ultrathin CoOx Nanosheets
• Ambient Ammonia Synthesis via Electrochemical Reduction of Nitrate Enabled by NiCo2O4 Nanowire Array
• Oxygen Vacancy-Mediated Selective C–N Coupling toward Electrocatalytic Urea Synthesis
• Potential-Driven Restructuring of Cu Single Atoms to Nanoparticles for Boosting the Electrochemical Reduction of Nitrate to Ammonia
• Ampere-level current density ammonia electrochemical synthesis using CuCo nanosheets simulating nitrite reductase bifunctional nature
• Intermetallic Single-Atom Alloy In–Pd Bimetallene for Neutral Electrosynthesis of Ammonia from Nitrate
• Fe/Cu diatomic catalysts for electrochemical nitrate reduction to ammonia

Cited by

• Cobalt-Based Electrocatalysts for Sustainable Nitrate Conversion: Structural Design and Mechanistic Advancements
• Oxygen-bridged electronic coupling of Ir single-atom sites for durable acidic oxygen evolution reaction

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