Effect of the residual silver and adsorbed lead anions towards the electrocatalytic methanol oxidation on nanoporous gold in alkaline media

Olaya, Alex Ricardo Silva; Zandersons, Birthe; Wittstock, Günther

doi:10.1016/j.electacta.2021.138348

Cited by 8 publications

(31 citation statements)

References 71 publications

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“…As shown in a previous paper by Pb UPD and surface voltammetry, the removal of silver leads to an enlargement or formation of the {1 0 0} and {1 1 1} domains on the surface of the NPG ligaments. Those domains show a particularly high activity for MOR as shown by the selective fractional coverage of those domains by Pb UPD . If Ag is removed from the surface, the ligaments coarsen by surface diffusion of Au atoms and at the same time form larger {1 0 0} and {1 1 1} domains.…”

Section: Results and Discussionsupporting

confidence: 86%

“…Even the sample NPG_Ag-free exhibits a higher j p,MA1 than NPG_Ag15 and NPG_Ag19. This can only be rationalized by taking into account other consequences of the removal of Ag from the surface of the ligaments in NPG on the structural evolution of NPG . As shown in a previous paper by Pb UPD and surface voltammetry, the removal of silver leads to an enlargement or formation of the {1 0 0} and {1 1 1} domains on the surface of the NPG ligaments.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Additional coverage with a small amount of Ag UPD enhances the rate of step (1). However, a further increase of the Ag coverage poisons the active {1 0 0} and {1 1 1} domains, which is quite similar to that found before for Pb UPD …”

Section: Results and Discussionmentioning

confidence: 99%

“…The exact impact of the Ag content on MOR could not be rationalized . Subsequently, we demonstrated that residual Ag shifts the onset potential for the MOR to less positive values compared to a sample where the residual Ag was removed . Following a kinetic analysis, it was shown that the residual Ag influences the Gibbs free energy Δ G rds of the rate-determining step.…”

Section: Introductionmentioning

confidence: 99%

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Promoting Effect of the Residual Silver on the Electrocatalytic Oxidation of Methanol and Its Intermediates on Nanoporous Gold

et al. 2022

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Nanoporous gold (NPG) obtained by dealloying Ag75Au25 with an overall residual Ag content of less than 1% was investigated as an electrocatalyst for the oxidation of methanol, formaldehyde, and formate in aqueous 0.1 M NaOH solution. The NPG was used to fill cavity microelectrodes, which allowed the recording of well-resolved voltammetry from the porous material. NPG differs from polycrystalline Au (Au(poly)) by its microstructure and its residual Ag content and also behaves distinctly different than Au(poly). The residual Ag content is higher at the surface of the ligaments than in the bulk. By cycling the NPG electrodes in 0.1 M H2SO4, the surface concentration of Ag could be decreased. It could then be set to a defined value by underpotential deposition (UPD) of Ag. The surface structure, and specifically its evolution upon the removal of Ag from the surface, was analyzed by the characteristic voltammetric features of Pb UPD. The effect of Ag on the electrocatalytic methanol oxidation reaction (MOR) is different in different potential regions. Ag coverage shifts the onset of the methanol oxidation current to less positive potentials. In the range of the peak current density, only a defined low Ag concentration enhanced the MOR current density compared to the Ag-free NPG. The {1 0 0} and {1 1 1} facets contributed the largest current, as concluded from selective poisoning experiments. At a potential of 1.63 V vs RHE, Ag2O at the surface is oxidized to AgO. Those layers can oxidize methanol and formate to CO2. The oxidation of formaldehyde proceeds at a much higher reaction rate than the MOR and formate oxidation; the reaction leads to CO and CO2 depending on the applied potential. Given the high oxidation rate of formaldehyde, it would be immediately further oxidized should it be formed as an intermediate of MOR. This is an important difference to the methanol oxidation at Pt. The water oxidation that occurs at the same potential range in the methanol-free solution was suppressed during CO2 formation.

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Section: Results and Discussionsupporting

confidence: 86%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Promoting Effect of the Residual Silver on the Electrocatalytic Oxidation of Methanol and Its Intermediates on Nanoporous Gold

et al. 2022

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“…[7][8][9] The starting materials for manufacturing porous metals as particles or surfaces, as is used in the present item, are alloys from which the less noble metal is dissolved out. 7,10,11 For example, in, ref. [11][12][13] the authors fabricated gold (Au) and hybrid Au/Al 2 O 3 porous nanoparticles (NPs) via a furnace annealing process at 850 C or 900 C and a subsequent dealloying process.…”

Section: Introductionmentioning

confidence: 99%

Porous spherical gold nanoparticles via a laser induced process

et al. 2022

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Production of NiCoMo-Supported Ni Foam for Electrocatalytic Oxidation of Methanol: Experimental and RSM Analysis

Doğru Mert,

Demir,

Edis

et al. 2024

Arab J Sci Eng

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The Ni-, Co-, and Mo-supported Ni foam (NiF–NiCoMo) was produced via galvanostatic method, and electrooxidation of methanol in alkaline medium was examined. The characterization was achieved using field emission scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction analysis. The electrochemical behavior was determined via cyclic voltammetry and chronoamperometry analysis. The contribution of each transition metal to electrocatalytic performance of NiF was monitored via mono, binary, and ternary modifications of each transition metal (Ni, Co, and Mo) for several amounts (5, 10, and 15 μg). Experiments were performed to determine the influence of catalyst amounts, methanol concentration, and scan rate parameters. The impacts of independent parameters on methanol electrooxidation were statistically investigated using Design-Expert software. The ability to analyze multiple parameters with a limited number of experimental performances is one of the method’s key benefits. The developed model showed that 9.41 and 14.03 µg catalyst amounts were the appropriate values for NiF–NiMo and NiF–NiCoMo achieving optimal circumstances, respectively.

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Effect of the residual silver and adsorbed lead anions towards the electrocatalytic methanol oxidation on nanoporous gold in alkaline media

Cited by 8 publications

References 71 publications

Promoting Effect of the Residual Silver on the Electrocatalytic Oxidation of Methanol and Its Intermediates on Nanoporous Gold

Promoting Effect of the Residual Silver on the Electrocatalytic Oxidation of Methanol and Its Intermediates on Nanoporous Gold

Porous spherical gold nanoparticles via a laser induced process

Production of NiCoMo-Supported Ni Foam for Electrocatalytic Oxidation of Methanol: Experimental and RSM Analysis

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