The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry

Joo, Jiyong; Uchida, Tatsuo; Cuesta, Ángel; Koper, Marc T. M.; Osawa, Masatoshi

doi:10.1016/j.electacta.2014.02.040

Cited by 135 publications

(154 citation statements)

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“…8,9,[20][21][22] However, unlike the process of CO electrooxidation reaction (E > 0.9 V), 27 the FAO is verified at potentials significantly lower (0.5 V ≤ E ≤ 0.9 V). Thus, the addition of CO in the solution where the FAO is taking place could give information about the role of CO ad on it.…”

Section: Resultsmentioning

confidence: 99%

“…15 It was found that the OCP value in the 0. solution is 0.25 V (Figure 3a). The voltammetric stripping carried out from this potential in the solution free of HCOOH (Figure 3b) shows an electrooxidation peak at 0.76 V. Both, electrochemical, 28,29 and spectroscopic, 8,9,[20][21][22] evidences indicate that this peak corresponds to the CO ad species. Thus, it is likely that in these conditions the following spontaneous dissociative adsorption is produced,…”

Section: Discussionmentioning

confidence: 99%

“…There is also a general consensus in that the contribution of the indirect path involving CO ad is almost negligible. [7][8][9][10][11]21 In relation to the direct path, HCOO ad was historically considered as the active intermediate, leading to the formation of CO 2 through the following rate determining step, However, it was recently proposed by different authors that reaction 1 is not taking place and that HCOO ad is just a spectator. 8,9,12,20 This conclusion was based on the absence of a linear relationship between the HCOO ad band intensity (I HCOO ), a measure of surface coverage (θ HCOO ), and the oxidation current (I).…”

mentioning

confidence: 99%

“…to voltammetric scans, which enabled the identification of the adsorbed species, as well as their localization in a given potential region of the potentiodynamic sweep. [7][8][9][10][11][20][21][22] The species detected through these techniques were CO ad and HCOO ad . There is also a general consensus in that the contribution of the indirect path involving CO ad is almost negligible.…”

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confidence: 99%

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Kinetic Study of the Formic Acid Oxidation on Steady State Using a Flow Cell

Luque

Chialvo

2017

J. Electrochem. Soc.

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The formic acid oxidation (FAO) reaction is studied on platinum in acid solutions using a specially designed flow cell and different experimental techniques, such as open circuit potential decay, chronoamperometry, voltammetric stripping, HCOOH concentration pulses and rotating disc electrode. It allows for the first time the evaluation of the surface coverage of irreversibly adsorbed reaction intermediates on steady state conditions. It is found that the unique species adsorbed irreversibly is CO (E < 0.5 V). It is demonstrated that at higher potentials the adsorption of the intermediate species involved in the FAO is highly reversible and their decomposition is the rate determining step. From the analysis of the results and taken into account available spectroscopic measurements, a new reaction mechanism is proposed, which is compatible with all the known experimental evidences and allows the interpretations of previous unexplained results. The formic acid oxidation (FAO) on metallic electrodes has been intensely studied, particularly because among several candidate fuels for low temperature fuel cells, HCOOH is considered one of the most promising.1,2 However, in spite of the attention paid to this reaction on platinum, its kinetic mechanism remains uncertain. The different authors only agree in that the reaction mechanism involves basically two parallel pathways, direct and indirect respectively.2-12 The direct path starts from the HCOOH electroadsorption step giving an active intermediate, which is then oxidized to CO 2 . Meanwhile, the adsorbed carbon monoxide intermediate is formed in the indirect pathway. In this context, it should be taken into account that at room temperature formic acid is thermodynamically unstable, as its decomposition through both dehydrogenation and dehydration processes has negative values of the reaction Gibbs free energies, although the corresponding reaction rates are negligible. [13][14][15] However, in contact with metals such as those usually employed as electrocatalysts, the spontaneous decomposition is strongly catalyzed, involving adsorbed species. [13][14][15] In electrochemistry this situation corresponds to the open circuit potential (OCP). Consequently, the kinetic studies of the formic acid electrooxidation should consider the simultaneous occurrence of both processes, catalytic (dehydrogenation and/or dehydration) and electrocatalytic (direct and/or indirect), which are coupled by reaction intermediates that are common to both.On the other hand, the revision of the literature indicates that the kinetic study of the FAO was preferably carried out on the basis of the voltammetric response in a solution of HCOOH with H 2 SO 4 or HClO 4 as supporting electrolyte. [2][3][4][5][6][7][8][9][10][11][12] There are some studies that have also used chronoamperometric measurements, 7-11,16 dynamic electrochemical impedance spectroscopy 17,18 and hydrodynamic impedance spectroscopy. 19 In the latter case, a no significant mass transfer effect was reported in the voltammetric an...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Kinetic Study of the Formic Acid Oxidation on Steady State Using a Flow Cell

Luque

Chialvo

2017

J. Electrochem. Soc.

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“…However, DLFC using formic acid has & Mônica H. M. T. Assumpção monicahelena@ufscar.br several engineering challenges such as: (i) the oxidation reactions are kinetically sluggish in acid media; (ii) the catalysts are susceptible to be poisoned and (iii) the environment of the fuel cell is corrosive [12,16]. In order to improve the use of formic acid, the use of formate in alkaline solutions has been intensely studied for fuel cell applications [3,11,[17][18][19][20]. The change from the acid media to the alkaline can dramatically improve kinetics of the oxygen reduction reaction (ORR) and also formate oxidation.…”

Section: Introductionmentioning

confidence: 99%

Use of PtAu/C electrocatalysts toward formate oxidation: electrochemical and fuel cell considerations

Silva

Buzzo

et al. 2016

Mater Renew Sustain Energy

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This study reports the use of PtAu/C electrocatalysts with different atomic ratios (90:10, 70:30 and 50:50) supported on Vulcan XC 72 carbon and prepared by the sodium borohydride method toward formate electrooxidation in alkaline media. The materials were characterized by X-ray diffraction, showing peaks characteristics of Pt and Au face-centered-cubic structures, and also by transmission electron micrographs that show the nanoparticles well dispersed on carbon and a mean particle size between 4 and 5 nm for all electrocatalysts. Electrochemical experiments show PtAu/C as promising catalysts toward formate oxidation, while single cell experiments reveal PtAu/C 90:10 as the best material since it provides a power density higher than Pt/C. The incorporation of Au could increase formate oxidation for more than one reason: (i) a facilitated rupture of C-H bond; (ii) the Au/oxide interface or (iii) by regenerating active sites.

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Formic Acid to Power towards Low‐Carbon Economy

Dutta

Chatterjee

Cheng

et al. 2022

Advanced Energy Materials

136

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The corresponding global annual carbon dioxide (CO 2 ) emissions had also increased from 23.1 gigatonnes of CO 2 (Gt CO2 ) in 2000 to 33.2 Gt CO2 in 2018. The excessive reliance on fossil fuels has caused the atmospheric CO 2 concentration to increase from the pre-industrial 280 ppm in the 18th century to the annual average of more than 410 ppm nowadays, which is found to be positively correlated to climate change. [2] To alleviate the environmental issues and to find viable alternatives for depleting fossil fuel reserves, the development and largescale deployment of clean and sustainable energy systems is of utmost importance. The development of suitable energy carriers is necessary to enable energy storage and distribution and to overcome the deficiency due to the intermittency of renewable energy sources such as solar and wind power. The use of H 2 has a great potential to diversify energy sectors and to prepare for the future implementation of low-carbon electricity and renewable energy. H 2 fuel cell (FC) technology is considered mature and regarded as the only technology to realize mobility without change of habits. As stated in the 2019 report by International Energy Agency to G20, H 2 is expected "to play a key role in a clean, secure and affordable energy future." [3] However, due to the lack of viable technologies for safe, efficient, and economical storage and transportation of H 2 , the applications of hydrogen have significantly been limited. [4] The storage and utilization of low-carbon electricity and decarbonization of transportation are essential components for the future energy transition into a low-carbon economy. While hydrogen has been identified as a potential energy carrier, the lack of viable technologies for safe and efficient storage and transportation of H 2 greatly limits its applications and deployment at scale. Formic acid (FA) is considered one of the promising H 2 energy carriers because of its high volumetric H 2 storage capacity of 53 g H 2 /L, and relatively low toxicity and flammability for convenient and low-cost storage and transportation. FA can be employed to generate electricity either in direct FA fuel cells (FCs) or indirectly as an H 2 source for hydrogen FCs. FA can enable large-scale chemical H 2 storage to eliminate energy-intensive and expensive processes for H 2 liquefaction and compression and thus to achieve higher efficiency and broader utilization. This perspective summarizes recent advances in catalyst development for selective dehydrogenation of FA and high-pressure H 2 production. The advantages and limitations of FA-to-power options are highlighted. Existing life cycle assessment (LCA) and economic analysis studies are reviewed to discuss the feasibility and future potential of FA as a fuel.

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The effect of pH on the electrocatalytic oxidation of formic acid/formate on platinum: A mechanistic study by surface-enhanced infrared spectroscopy coupled with cyclic voltammetry

Cited by 135 publications

References 68 publications

Kinetic Study of the Formic Acid Oxidation on Steady State Using a Flow Cell

Kinetic Study of the Formic Acid Oxidation on Steady State Using a Flow Cell

Use of PtAu/C electrocatalysts toward formate oxidation: electrochemical and fuel cell considerations

Formic Acid to Power towards Low‐Carbon Economy

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