Mechanistic changes observed in heavy water for nitrate reduction reaction on palladium-modified Pt(hkl) electrodes

Souza-Garcia, Janaína; Ticianelli, Edson A.; Climent, Vı́ctor; Feliu, Juan M.

doi:10.1039/c2sc20490h

Cited by 18 publications

(12 citation statements)

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“…DEMS has since been developed extensively, particularly through the work of Helmut Baltruschat and coworkers [14,15,16], and has become a widely used method in electrocatalysis research [17,18,19,20]. DEMS has proven especially useful in fundamental electrochemical studies, for example comparing the product distribution of a Faradaic process on different crystal facets [21,22,23]. A notable variation on DEMS, termed on-line mass spectrometry (OLEMS), developed by Marc Koper and coworkers [24,25,26] and now used by several groups [27,28], involves a small PTFE vacuum inlet at the end of a glass tube as an EC-MS probe, scaled such that the flux to the mass spectrometer is sufficiently small that no differential pumping is needed.…”

Section: Introductionmentioning

confidence: 99%

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Trimarco

Scott

Thilsted³

et al. 2018

Electrochimica Acta

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Section: Introductionmentioning

confidence: 99%

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Trimarco

Scott

Thilsted³

et al. 2018

Electrochimica Acta

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“…Nitrate reduction at metal electrode surfaces has been the subject of intensive research over many years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], due in many respects to its relevance to several topical environmental concerns such as groundwater remediation (denitrification) [19][20][21], nuclear waste management [22] and food safety [23]. The complexity of this electrochemical reaction is broadly acknowledged [13] and may be ascribed, at its most basic level, to the many oxidation states (+5 to -3) available to nitrogen-containing nitrate reduction reaction intermediates (e.g.…”

Section: Introductionmentioning

confidence: 99%

Nitrate anion reduction in aqueous perchloric acid as an electrochemical probe of Pt{1 1 0}-(1 × 1) terrace sites

Attard

Souza-Garcia

Martínez‐Hincapié

et al. 2019

Journal of Catalysis

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The electrochemical reduction of nitrate anions in aqueous 0.1 M perchloric acid has been studied using Pt(S)-[n{110}x{111}] and Pt(S)-[n{110}x{100}] single crystal electrodes. It is demonstrated that the presence of Pt{110} adsorption sites is associated with a single, broad nitrate reduction peak centred at 0.18 V (RHE). Moreover, depending on the cooling environment used after flame-annealing (CO, H2, Ar, air, nitrogen), the surface concentration of such sites varies which in turn regulates the nitrate reduction current density achievable for a given stepped Pt{hkl} electrode. The origin of this phenomenon is the propensity of the clean Pt{110} basal plane (and vicinal surfaces containing this plane) to reconstruct towards a stable (1x2) phase with strong CO chemisorption favouring formation of larger Pt{110}-(1x1) domains. In contrast, argon/air-cooling appears to promote the development of a largely (1x2) reconstructed surface which is much less active for nitrate reduction since the surface density of Pt{110}-(1x1) terrace sites is significantly diminished. Interestingly, hydrogen-cooling affords nitrate reduction activity intermediate between these two extremes. We suggest that under this particular preparation condition, a partially deconstructed (1x1) phase forms containing the "excess" 50% of surface atoms (originating from the (1x2) phase) sitting proud of the surface in the form of small (1x1) islands, together with residual (1x2) missing row

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“…Many efforts have been devoted to disentangle its oxidation mechanism and how this mechanism depends on the ethanol concentration and the surface structure and composition of the electrode. [1][2][3][4] The goal is to obtain CO2 as final product at the lowest potential and the highest current. In the oxidation mechanism, three different products can be obtained: acetaldehyde, acetic acid and CO2, exchanging 2, 4 and 12 electrons respectively.…”

Section: Unusually High Activity Of Pt Islands On Rh(111) Electrodes mentioning

confidence: 99%

Unusually High Activity of Pt Islands on Rh(1 1 1) Electrodes for Ethanol Oxidation

et al. 2013

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The electrooxidation of ethanol has been widely studied since its possible application in PEM cells. Many efforts have been devoted to disentangle its oxidation mechanism and how this mechanism depends on the ethanol concentration and the surface structure and composition of the electrode. [1][2][3][4] The goal is to obtain CO2 as final product at the lowest potential and the highest current. In the oxidation mechanism, three different products can be obtained: acetaldehyde, acetic acid and CO2, exchanging 2, 4 and 12 electrons respectively. Acetic acid is a stable product since its oxidation takes place at very high potentials [5] , thus the challenge is to break the C-C bond either in ethanol [6,7] or acetaldehyde [8] to obtain CO2.Among pure metals, platinum has the highest catalytic activity in acid media, but the final product in the oxidation is mixture of CO2 and acetic acid, whose ratio strongly depends on the surface structure. [9] In order to increase the activity of platinum, other metals, namely, Ru, [8,10] Os, [11,12] Sn [7] and Rh [13] have been added to the surface to diminish the overpotentials and to increase the selectivity of the oxidation towards the formation of CO2. The effect of these metals in the oxidation mechanism has been explained on the basis of the bifunctional mechanism [14] and ligand effect. [15] From previous results, it seems clear that the only surface modifier that increases the CO2/acetaldehyde ratio is Rh, [13] although the overall reaction rate is lower. On the other hand, the opposite combination, Pt deposited on Rh electrodes has not been studied yet. Rh electrodes are not active for the oxidation of ethanol. However, it has been shown that a single layer (or submonolayer) of a metal deposited on a different substrate can have electrocatalytic activities larger than any of the two bulk metals. [16,17] In general, the metal overlayer has interatomic distances that are different from the bulk metal, since it accommodates its structure to that of the underneath substrate. This effect causes a change in the electronic properties of the overalyer and can increase (or decrease) the catalytic properties.[18] The aim of this work is to determine the electrochemical behaviour of Rh electrodes modified by Pt (sub)monolayers for ethanol oxidation, analysing the effect of the surface composition on the mechanism using in situ FTIR spectroscopy. [19] For the clean Rh(111) electrode, the voltammogram in sulphuric acid solution shows a pair of quasi-reversible peaks at 0.15 and 0.06 V, which are associated to the competitive adsorption of hydrogen/sulphate on the electrode surface. [20,21] In the initial deposition stages of Pt, these peaks become significantly sharper and more reversible. Although the explanation on the origin of such change is beyond the scope of this manuscript, it should be recalled that the interaction of water with adsorbates is different on platinum and rhodium. For instance water and CO adsorbed on Pt(111) show repulsive interactions whereas attractive interac...

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Mechanistic changes observed in heavy water for nitrate reduction reaction on palladium-modified Pt(hkl) electrodes

Abstract: 2012Mechanistic changes observed in heavy water for nitrate reduction reaction on palladiummodified Pt(hkl) electrodes CHEMICAL SCIENCE, CAMBRIDGE, v. 3, n. 10, supl

Cited by 18 publications

References 33 publications

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Nitrate anion reduction in aqueous perchloric acid as an electrochemical probe of Pt{1 1 0}-(1 × 1) terrace sites

Unusually High Activity of Pt Islands on Rh(1 1 1) Electrodes for Ethanol Oxidation

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Mechanistic changes observed in heavy water for nitrate reduction reaction on palladium-modified Pt(hkl) electrodes

Abstract: 2012Mechanistic changes observed in heavy water for nitrate reduction reaction on palladiummodified Pt(hkl) electrodes CHEMICAL SCIENCE, CAMBRIDGE, v. 3, n. 10, supl

Cited by 18 publications

References 33 publications

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Enabling real-time detection of electrochemical desorption phenomena with sub-monolayer sensitivity

Nitrate anion reduction in aqueous perchloric acid as an electrochemical probe of Pt{1 1 0}-(1 × 1) terrace sites

Unusually High Activity of Pt Islands on Rh(1 1 1) Electrodes for Ethanol Oxidation

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Nitrate anion reduction in aqueous perchloric acid as an electrochemical probe of Pt{1 1 0}-(1 × 1) terrace sites