Electrocatalytic nitrate reduction with Co-based catalysts: comparison of DIM, TIM and cyclam ligands

Kwon, Hyuk‐Yong; Braley, Sarah E; Madriaga, Jose P; Smith, Jeremy M.; Jakubı́ková, Elena

doi:10.1039/d1dt02175c

Cited by 9 publications

(17 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of redox innocent ligands such as cyclam, the onset potential for electrocatalysis is therefore dictated by the potential required to access Co(I). While the ability of redox noninnocent ligands to store electrons makes access to the equivalent redox state in these complexes more accessible, relatively cathodic potentials are still required . We anticipate that ligands that better stabilize the formally Co(I) state in aqueous solution will allow for nitrate reduction electrocatalysis with smaller overpotentials.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, [Co(DIM)Br 2 ] + reduces NO 3 − at −0.90 V SCE , whereas [Co(cyclam)Br 2 ] + has an onset potential of −1.30 V SCE . 15 Together, these studies suggest a list of ligand design criteria for a molecular electrocatalyst that is active toward NO 3 − and NO 2 − reduction. As exemplified by [Co(DIM)Br 2 ] + (Figure 2), 13,14 a macrocycle that provides a combination of redox noninnocent character, possible proton shuttles, and flexibility is likely to create a metal complex that is catalytically active toward NO x − reduction.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The redox noninnocence of the DIM ligand allows reducing equivalents to be stored throughout these complexes, in contrast to the redox innocent cyclam ligand. Indeed, [Co(DIM)Br 2 ] + reduces NO 3 – at −0.90 V SCE , whereas [Co(cyclam)Br 2 ] + has an onset potential of −1.30 V SCE …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electrocatalytic Reduction of Nitrogen Oxyanions with a Redox-Active Cobalt Macrocycle Complex

et al. 2022

Self Cite

View full text Add to dashboard Cite

The cobalt complex, [Co(CR)Br2]+, where CR is the redox-active macrocycle 2,12-dimethyl-3,7,11,17-tetraazabicyclo-[11.3.1]-heptadeca-1(17),2,11,13,15-pentaene, has been investigated for the electrocatalytic reduction of aqueous NO2 – and NO3 –. At neutral pH, the bromide ligands are hydrolyzed, providing [Co(CR)(OH2)(OH)]2+ as the major species in aqueous solution. In the presence of nitrite, [Co(CR)(NO2)2]+ is formed as the major species in solution and is a precursor to the electrocatalytic reduction of NO2 –, which is selectively converted to ammonium with high Faradaic efficiency. There is evidence for both homogeneous and heterogeneous electrocatalysis. Although similar NO3 – binding is not observed, electrocatalytic reduction to ammonium also occurs, albeit with a lower Faradaic efficiency. In this case, NO2 – is generated as an intermediate product of NO3 – reduction.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrocatalytic Reduction of Nitrogen Oxyanions with a Redox-Active Cobalt Macrocycle Complex

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…This complex is of particular interest because hydrogen-bonding to nitrate has been studied in the design of molecular receptors 33 as well as in the context of electrocatalytic nitrate reduction for environmental remediation. 34,35 In conclusion, we have shown that the di(2-methylthiazolidinyl)pyridine ligand framework can support first-row transition metals and can also accommodate one or two deprotonation events to form the resulting thiolate-bound iminopyridine-and diiminopyridine-supported complexes. As such, this framework can be both proton-active and, in its iminopyridine and diiminopyridine forms, redox-active.…”

mentioning

confidence: 77%

mentioning

confidence: 99%

Cluster self-assembly and anion binding by metal complexes of non-innocent thiazolidinyl–thiolate ligands

et al. 2022

View full text Add to dashboard Cite

show abstract

Reactive Separation of Ammonia from Wastewater Nitrate via Molecular Electrocatalysis

Liu

Miller

Tarpeh

2023

Environ. Sci. Technol. Lett.

View full text Add to dashboard Cite

Selective electrochemical conversion of nitrate to ammonia with ammonia capture can simultaneously remediate nitrate-polluted wastewater and supplement Haber-Bosch ammonia production. Homogeneous molecular catalysts remain underexplored in wastewater treatment and, more generally, in reactive separation processes. Despite the tunable reactivity of molecular catalysts, two barriers prevent their widespread implementation for wastewater nitrate treatment and ammonia recovery. The first barrier is the lack of reports of reaction activity and selectivity of nitrate reduction molecular catalysts in real wastewaters. The second barrier is the need to separate the catalyst, catalytic product, and treated wastewater. In this study, we employ electrochemical stripping in several configurations as a reactive separation unit process to address both barriers to implementation. Using the homogeneous molecular nitrate reduction catalyst Co(DIM), we demonstrate >70% removal of nitrate from municipal wastewater treatment plant secondary effluent with >98.5% selectivity to ammonia, leading to the generation of a high-purity ammonia product (ammonium sulfate). These experiments constitute a novel demonstration of molecular catalysis for nitrate reduction in real wastewater and highlight electrochemical engineering opportunities in reactive separations to valorize wastewater resources. This work advances environmental research toward United Nations Sustainable Development Goals (SDGs) for Clean Water (SDG 6) and Responsible Consumption and Production (SDG 12).

show abstract

Electrocatalytic nitrate reduction with Co-based catalysts: comparison of DIM, TIM and cyclam ligands

Abstract: Over the past century, the global concentration of environmental nitrate has increased significantly from human activity, which has resulted in the contamination of drinking water and aquatic hypoxia around the...

Cited by 9 publications

References 31 publications

Electrocatalytic Reduction of Nitrogen Oxyanions with a Redox-Active Cobalt Macrocycle Complex

Electrocatalytic Reduction of Nitrogen Oxyanions with a Redox-Active Cobalt Macrocycle Complex

Cluster self-assembly and anion binding by metal complexes of non-innocent thiazolidinyl–thiolate ligands

Reactive Separation of Ammonia from Wastewater Nitrate via Molecular Electrocatalysis

Contact Info

Product

Resources

About