Poisoning and Activation of the Gold Cathode during Electroreduction of  CO 2

Kędzierzawski, P.; Augustyński, Jan

doi:10.1149/1.2054936

Cited by 74 publications

(63 citation statements)

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“…It was experimentally observed that the CO signal is restored to its initial value only after potential excursion to higher potential (close to 1.0 V), but the subsequent polarization at negative values for CO 2 reduction leads to the same signal behavior of deactivation. This deactivation or poisoning of gold during the CO 2 electroreduction to CO was also observed by Kedzierzawski et al 71 Based on the results of cyclic voltammetry, conducted after experiments of polarization for CO 2 electroreduction, they stated that adsorbed CO is not the cause of the observed deactivation of the gold electrode. Some other adsorbed reaction intermediate, that suffers electrochemical oxidation at potentials higher than that for CO, is likely to be the reason for such observed deactivation.…”

Section: Electrochemical Experiments Electrocatalytic Reduction Of Cosupporting

confidence: 73%

Investigation of Electrocatalysts for Selective Reduction of CO2 to CO: Monitoring the Reaction Products by on line Mass Spectrometry and Gas Chromatography

Camilo¹,

Silva²,

Lima³

2017

J. Braz. Chem. Soc.

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The carbon dioxide electrocatalytic reduction is central for the development of regenerative cycles of electrochemical energy conversion and storage. Herein, the gaseous products of the CO 2 electroreduction were monitored by using an electrochemical cell on line coupled to a differential electrochemical mass spectrometer (DEMS), aiming at searching for electrocatalysts with high selectivity for CO formation. The results showed that, among the studied materials, the Cu 4 Sn/C alloy nanoparticles were stable during potentiostatic polarizations as revealed by in situ X-ray absorption spectroscopy (XAS), and the on line DEMS measurements showed the production of CO, suppression of methane and ethylene formations, and diminishing of the hydrogen evolution reaction, in relation to that on pure Cu 2 O-Cu/C. The faradaic efficiencies for CO formation were 13 and 23% for Cu 4 Sn/C and Au/C (a known electrocatalyst for CO), respectively, determined by experiments of in line gas chromatography (GC). The selectivity of Cu 4 Sn/C for CO formation was ascribed to the role of Sn atoms on stabilizing adsorbed HCOO intermediates, and hindering further hydrogenation, letting CO free for desorption. These results are expected to be used as a guide for further development of electrocatalysts with a fine-tuning of composition for increasing the faradaic efficiency of CO 2 electroreduction to CO.Keywords: CO 2 electrochemical reduction, on line DEMS, in line GC, CO formation, Cu 4 Sn/C alloy IntroductionConcomitantly with the growth of the world population, the energy demand is increasing. To satisfy this scenario, fossil fuels, such as oil, coal and natural gas, are being exhaustively used. Unfortunately, together to the dependence on these fuels, large amounts of carbon dioxide (CO 2 ) are emitted into the environment and, so, this is not a sustainable cycle. This has initiated research projects to investigate efficient processes for using the available CO 2 in the atmosphere. The electrochemical reduction of carbon dioxide is, in principle, an efficient manner that can be explored. In this context, the electroreduction of CO 2 to fuels with high-energy density or to industrial chemicals, that can be further processed to produce useful fuels, such as CO, using photovoltaic panels, with the consecutive utilization as fuel in fuel cells, would define a sustainable or regenerative cycle. [1][2][3][4][5][6][7] In the case of performing the CO 2 electroreduction to CO in parallel with the water electroreduction (or the hydrogen evolution reaction (HER)), the mixture CO + H 2 (syngas) is produced. 8,9 In the chemical industry, CO/H 2 mixtures are reacted to form methanol or other liquid fuels, such as diesel, by using the Fischer-Tropsch process. 10 The CO 2 electrochemical reduction can be productselective by using different electrocatalysts. However, even for two-electron products, it is decisive to know the kinetically important steps of the studied reaction. Also, synthesizing an optimized electrocatalyst that do not catalyze undesi...

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Section: Electrochemical Experiments Electrocatalytic Reduction Of Cosupporting

confidence: 73%

Investigation of Electrocatalysts for Selective Reduction of CO2 to CO: Monitoring the Reaction Products by on line Mass Spectrometry and Gas Chromatography

Camilo¹,

Silva²,

Lima³

2017

J. Braz. Chem. Soc.

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“…At −0.70 V, CO production on polycrystalline Au foil electrodes operated in native C i electrolytes commences with ~60% Faradaic efficiency but declines to ~10% over the course of 2 hours (Figure 2A, black squares, error bars shown in Figures 2-4 are the standard deviation of three independent measurements) consistent with literature reports. 32,34 The large error bars observed for electrolyses performed in native C i electrolyte reveal a high degree of run-to-run variability, consistent with trace metal impurities strongly influencing catalytic efficiency. Catalyst deactivation for CO production is accompanied by a rise, from ~23% to ~77%, in Faradaic efficiency for the hydrogen evolution reaction (HER).…”

Section: Resultsmentioning

confidence: 90%

“…[23][24][25][26][27][28][29][30][31] However, planar group 11 metal surfaces are known to lose their catalytic activity and selectivity for CO 2 reduction over the time scale of minutes to hours under steady state electrolysis. 22,[32][33][34][35][36][37] For example, copper surfaces lose one-half of their catalytic activity for methane production within 20 min of polarization, 33,35 and CO production selectivity on Au 32 and Ag 34 decreases within minutes of electrolysis. Despite posing a clear obstacle to practical implementation of CO 2 reduction technologies, the mechanistic basis for this activity loss remains poorly understand.…”

Section: Introductionmentioning

confidence: 99%

“…Based on these hypotheses, contemporary strategies to prolonging catalyst lifetimes include periodic oxidative pulsing of the electrode to remove adsorbed organics [32][33][34] and long-term (>9 hrs) pre-electrolysis using a sacrificial electrode to scavenge trace metal ion impurities in the electrolyte. 35 The former is impractical because it progressively alters the catalyst surface structure 42 , and pre-electrolysis has been shown, in many cases, to be ineffective 43,44 and irreproducible, 33,34 and is both energy and time intensive.…”

Section: Introductionmentioning

confidence: 99%

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Impurity Ion Complexation Enhances Carbon Dioxide Reduction Catalysis

2015

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Herein, we show that group 11 CO 2 reduction catalysts are rapidly poisoned by progressive deposition of trace metal ion impurities existent in high purity electrolytes. Metal impurity deposition was characterized by XPS and in situ stripping voltammetry and is coincident with loss of catalytic activity and selectivity for CO 2 reduction, favoring hydrogen evolution on poisoned surfaces. Metal deposition can be suppressed by complexing trace metal-ion impurities with ethylenediaminetetraacetic acid or solid supported iminodiacetate resins. Metal ion complexation allows for reproducible, sustained catalytic activity and selectivity for CO 2 reduction on Au, Ag, and Cu electrodes. Together, this study establishes the principle mode by which group 11 CO 2 reduction catalysts are poisoned and lays out a general approach for extending the lifetime of electrocatalysts subject to impurity metal deposition.

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“…Generally, to address such problem, the electrocatalytic activity of metal electrodes is enhanced prior to their use; the enhancement is based on thermal, 4 chemical, 5 cathodic 6 (application of a potential at which hydrogen is generated), and anodic treatment 1,2,7,8 (formation of metal oxide and its subsequent reduction). In particular, multiple anodic treatments of metal electrodes offer highly enhanced electrocatalytic activity, which even enables one to observe substantial currents of hydrogen sorption and desorption at Au electrodes.…”

mentioning

confidence: 99%