A re-evaluation of Sn(II) phthalocyanine as a catalyst for the electrosynthesis of ammonia

Shipman, Michael; Symes, Mark D.

doi:10.1016/j.electacta.2017.11.105

Cited by 32 publications

(28 citation statements)

References 29 publications

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“…immersing an electrode into a solution), or upon electrochemical stimuli. For example, materials like nitrides 24,25 and phthalocyanines 26 that have been tested as NRR catalysts were all found to decompose under reductive potentials with the formation of ammonia through a non-electrocatalytic reaction in aqueous electrolytes.…”

Section: Potential Origins Of False Nrr Positivesmentioning

confidence: 99%

Identification and elimination of false positives in electrochemical nitrogen reduction studies

et al. 2020

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Ammonia is of emerging interest as a liquefied, renewable-energy-sourced energy carrier for global use in the future. Electrochemical reduction of N2 (NRR) is widely recognised as an alternative to the traditional Haber–Bosch production process for ammonia. However, though the challenges of NRR experiments have become better understood, the reported rates are often too low to be convincing that reduction of the highly unreactive N2 molecule has actually been achieved. This perspective critically reassesses a wide range of the NRR reports, describes experimental case studies of potential origins of false-positives, and presents an updated, simplified experimental protocol dealing with the recently emerging issues.

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Section: Potential Origins Of False Nrr Positivesmentioning

confidence: 99%

Identification and elimination of false positives in electrochemical nitrogen reduction studies

et al. 2020

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“…Recent retests of some reported catalysts have demonstrated that the NH 3 are originated from contaminants or decomposition of catalysts rather than from NRR. [ 100 ] To avoid these false positive results during NRR, establishing benchmarking protocols for control experiments and ammonia measurements have been proposed by several groups. [ 101 ] In addition to the difficulty of accurately detecting NRR‐generated NH 3 , the current most important issues in NRR electrocatalysis involve acquiring desirable activity and selectivity.…”

Section: Porous Nrr Electrocatalystsmentioning

confidence: 99%

Active Site Engineering in Porous Electrocatalysts

et al. 2020

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between electrical and chemical energy to store off-peak electricity produced from these resources. The opportunities relate to the fact that electrocatalytic reactions can be employed to convert these excess and off-peak electricity into chemical bonds in molecules. A fascinating prospect is the utilization of renewable electricity for the conversion of abundant resources such as H 2 O, N 2 , and CO 2 into synthetic fuels such as hydrogen, ammonia, hydrocarbons, and alcohols under ambient conditions (Figure 1). Through the reverse processes, clean electricity can be generated from the products, for example, via hydrogen-, ammonia-, or alcohol-powered fuel cells, ultimately resulting in a closed water cycle, nitrogen cycle, or carbon cycle. Hydrogen production via electrocatalytic water splitting, which may enable the hydrogen economy, is a notable example to these. [2] At present, the annual hydrogen production worldwide exceeds more than 65 million tons, mainly for industrial uses such as petroleum refining and ammonia synthesis. Unfortunately, most of the hydrogen is produced from fossil fuels through steam methane reforming and coal gasification and is accompanied by large emission of the greenhouse gas CO 2. Producing hydrogen from water using renewable electricity provides a green and sustainable pathway for future hydrogen energy cycle. In a similar vein, renewable energy-powered electrocatalysis of CO 2 and N 2 reduction produces high-value fuels or fine chemicals such as formic acid (HCOOH), carbon monoxide (CO), methanol (CH 3 OH), and ammonia (NH 3) under ambient conditions. [3] The use of these renewable fuels (e.g., hydrogen and alcohols), instead of petroleum-based fuels, for transportation applications is receiving unprecedented attention because the former are more environmentally friendly and sustainable. Fuel cell technologies based on these fuels can reliably supply electrical energy and are, thus, highly desired for running emerging electric vehicles. [4] To realize the water cycle, carbon cycle, and nitrogen cycle described above, the central reactions are the hydrogen evolution reaction (HER), the CO 2 reduction reaction (CO 2 RR), and the nitrogen reduction reaction (NRR), as well as the oxygenrelated reactions, including the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), which are important half reactions in electrolyzers and fuel cells, respectively. In these energy conversion processes, electrocatalysts are indispensable. The desired electrocatalysts should both Electrocatalysis is at the center of many sustainable energy conversion technologies that are being developed to reduce the dependence on fossil fuels. The past decade has witnessed significant progresses in the exploitation of advanced electrocatalysts for diverse electrochemical reactions involved in electrolyzers and fuel cells, such as the hydrogen evolution reaction (HER), the oxygen reduction reaction (ORR), the CO 2 reduction reaction (CO 2 RR), the nitrogen reduction reaction (NRR), and the oxyge...

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“…Finally, the commendable effort of Shipman and Symes whose report refutes the previously published activity of Sn(II) phthalocyanine on carbon foil in a 1 M KOH solution [46] should be mentioned. The group found that substituting the N 2 feed with Ar resulted in the same rate of NH 3 formation, proving that the source of NH 3 was not the NRR but the decomposition of the catalyst-electrode.…”

Section: Recent Experimental Findingsmentioning

confidence: 88%

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

et al. 2019

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Ammonia is a key chemical produced in huge quantities worldwide. Its primary industrial production is via the Haber-Bosch method; a process requiring high temperatures and pressures, and consuming large amounts of energy. In the past two decades, several alternatives to the existing process have been proposed, including the electrochemical synthesis. The present paper reviews literature concerning this approach and the experimental research carried out in aqueous, molten salt, or solid electrolyte cells, over the past three years. The electrochemical systems are grouped, described, and discussed according to the operating temperature, which is determined by the electrolyte used, and their performance is valuated. The problems which need to be addressed further in order to scale-up the electrochemical synthesis of ammonia to the industrial level are examined.

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A re-evaluation of Sn(II) phthalocyanine as a catalyst for the electrosynthesis of ammonia

Cited by 32 publications

References 29 publications

Identification and elimination of false positives in electrochemical nitrogen reduction studies

Identification and elimination of false positives in electrochemical nitrogen reduction studies

Active Site Engineering in Porous Electrocatalysts

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

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