Au-based bimetallic catalysts: how the synergy between two metals affects their catalytic activity

Sha, Jiahao; Paul, Sébastien; Dumeignil, Franck; Wojcieszak, Robert

doi:10.1039/c9ra06001d

Cited by 35 publications

(24 citation statements)

References 64 publications

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“…These results suggest a synergistic effect between Au and Pt, leading to an increased catalytic activity. This behaviour was also expected, such the synergy in the catalytic activity of bimetallic NPs is a well-known feature, extensively studied in chemical synthesis procedures among other reactions [34][35][36][37][38] , and being also found for Au@Pt NPs 39,40 .…”

Section: B)supporting

confidence: 65%

“…Pt has 5 been extensively studied, mainly because of its electrocatalytic 6 activity towards a wide variety of reactions, such as hydrogen 7 evolution, oxygen reduction, hydrogen peroxide reduction, hy-8 drogen oxidation, methanol oxidation, ethanol oxidation and 9 formic acid oxidation 32,33 . Pt scarcity and high cost makes de-10 sirable its combination with other metals to reduce costs and to 11 enhance its catalytic performance due to the synergistic effects 12 between metals [34][35][36][37][38] .…”

mentioning

confidence: 99%

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Bifunctional Au@Pt/Au core@shell Nanoparticles As Novel Electrocatalytic Tags in Immunosensing: Application for Alzheimer’s Disease Biomarker Detection

et al. 2020

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In this work, bifunctional core@shell Au@Pt/Au NPs are presented as novel tags for electrochemical immunosensing.Au@Pt/Au NPs were synthesized following a chemical route based on successive metal depositions and galvanic replacement reactions from the starting AuNPs. Au protuberances growth on the surface of Au@Pt NPs allowed their easy bioconjugation with antibodies, while the high catalytic Pt surface area was approached for their sensitive detection through the electrocatalysed water oxidation reaction (WOR) at neutral pH. Moreover, the synergy between Au and Pt metals on the NP surface also lead to an increased catalytic activity, improving the sensitivity of the NP detection. Cyclic voltammetry and chronoamperometry were used for the evaluation of the Au@Pt/Au NPs electrocatalytic activity towards WOR. The chronoamperometric current recorded at a fixed potential of +1.35 V was selected as the analytical signal, allowing the quantification of Au@Pt/Au NPs at 10 13 NPs/mL levels. The optimized electrocatalytic method was applied to the quantification of conformationally altered p53 peptide Alzheimer's disease (AD) biomarker in a competitive immunoassay using magnetic bead (MB) platforms at levels as low as 66 nM. The performance of the system in a real scenario was demonstrated analysing plasma samples from a cognitively healthy subject. This novel Au@Pt/Au NPs-based electrocatalytic immunoassay has the advantage, over common methods for NP tags electrochemical detection, of the signal generation in the same neutral medium where the immunoassay takes place (0.1 M PBS pH 7.2), avoiding the use of additional and more hazardous reagents and paving the way to future integrated biosensing systems. 38 trolled synthesis, higher stability against harsh conditions, 39 higher resistance to high concentrations of substrate and a lower 40 cost [3][4][5][6] . The use of electrocatalytic NPs as labels has been ex-41 tensively studied and applied in immunosensing [7][8][9][10][11][12] , offering 42 outstanding alternatives to traditional assays. 43Among the wide variety of NPs, metallic NP labels have at-44 tracted considerable interest due to their unique red-ox and op-45 tical properties 13,14 as well as their electrocatalytic activity, also 46 benefiting of the inherent advantages of the electrochemical de-47 tection in terms of sensitivity, selectivity, simplicity and low 48 cost 15 . In most cases highly acidic media are needed for such 49 NPs detection, either to facilitate dissolution 16 or as source of 50 hydrogen ions for further detection based on hydrogen evolu-51 tion reaction (HER) [17][18][19][20][21][22][23] . However, the use of acid solutions is 52 not desirable for both safety reasons and the time needed for the 53 analysis, also involving additional steps after the immunoassay. 54Consequently, there is a need of NP tags that may be detected 55 in the same medium where immunoreactions take place. In this 56 context, the water oxidation reaction (WOR) occurring at neu-57 tral pH and easily catalysed by some ...

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Section: B)supporting

confidence: 65%

mentioning

confidence: 99%

Bifunctional Au@Pt/Au core@shell Nanoparticles As Novel Electrocatalytic Tags in Immunosensing: Application for Alzheimer’s Disease Biomarker Detection

et al. 2020

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“…In our case, the catalytic activity also passes through the maximum for Au 4 Pd 1 composition. This is also in good agreement with the literature for liquid phase oxidation of glucose and benzyl alcohol [20,25]. It could be stated that an optimum ratio between Pd 0 and Pd 2+ species is necessary to maintain the high activity of these catalysts, as well to obtain high selectivity to desired products [20,38].…”

Section: Discussionsupporting

confidence: 90%

“…The low pH observed due to acid formation after the oxidation reactions did not increase the leaching of the metals to the solution (which was confirmed by ICP analysis). Considering that the reactions occurred in an acidic medium, lower reaction rates are justified when compared to the reactions performed in a neutral or alkaline medium [20,25]. This means that the concept for the development of catalysts for reactions in aqueous medium in the absence of a base was successful, although the search for an increase in catalytic efficiency for these systems remains topical.…”

Section: Discussionmentioning

confidence: 99%

5-Hydroxymethylfurfural and Furfural Base-Free Oxidation over AuPd Embedded Bimetallic Nanoparticles

et al. 2020

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The heterogeneous catalytic partial oxidation of alcohols and aldehydes in the liquid phase usually needs the addition of a homogeneous base, which in turn makes the products’ recovery cumbersome, and can further induce undesired side reactions. In the present work, we propose the use of novel catalysts based on metallic Au, Pd and bimetallic AuPd nanoparticles embedded in a titanosilicate matrix. The as-prepared catalysts showed good efficiency in the base-free partial oxidation of furfural and 5-hydroxymethylfurfural. Au4Pd1@SiTi catalyst showed high selectivity (78%) to monoacids (namely, 5-formyl-2-furancarboxylic acid and 5-hydroxymethyl-2-furancarboxylic acid) at 50% 5-hydroxymethylfurfural (HMF) conversion. The selectivity even reached 83% in the case of furfural oxidation to furoic acid (at 50% furfural conversion). The performances of the catalysts strongly depended on the Au–Pd ratio, with an optimal value of 4:1. The pH of the solution was always below 3.5 and no leaching of metals was observed, confirming the stabilization of the metal nanoparticles within the titanosilicate host matrix.

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“…In its turn, adsorption energy is dependent on the crystallite size, facets and composition, properties that are susceptible of changes by the formation of alloys in bimetallic systems. Besides, the rearranged atomic ordering admitted by alloys may change the surface electronic structure of the nanoparticles and, thus, affect their catalytic properties (Sha et al, 2019).…”

Section: Catalytic Reduction Of 2-nitroanilinementioning

confidence: 99%

Mechanochemical Strategies for the Preparation of SiO2-Supported AgAu Nanoalloy Catalysts

2022

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Silver-gold nanoalloys were prepared from their metal salts precursors through bottom-up mechanochemical synthesis, using one-pot or galvanic replacement reaction strategies. The nanostructures were prepared over amorphous SiO2 as an inert supporting material, facilitating their stabilization without the use of any stabilizing agent. The nanomaterials were extensively characterized, confirming the formation of the bimetallic nanostructures. The nanoalloys were tested as catalysts in the hydrogenation of 2-nitroaniline and exhibited up to 4-fold the rate constant and up to 37% increased conversion compared to the respective single metal nanoparticles. Our approach is advantageous to produce nanoparticles with clean surfaces with available catalytic sites, directly in the solid-state and in an environmentally friendly manner.

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Au-based bimetallic catalysts: how the synergy between two metals affects their catalytic activity

Abstract: Supported bimetallic nanoparticles are particularly attractive catalysts due to increased activity and stability compared to their monometallic counterparts.

Cited by 35 publications

References 64 publications

Bifunctional Au@Pt/Au core@shell Nanoparticles As Novel Electrocatalytic Tags in Immunosensing: Application for Alzheimer’s Disease Biomarker Detection

Bifunctional Au@Pt/Au core@shell Nanoparticles As Novel Electrocatalytic Tags in Immunosensing: Application for Alzheimer’s Disease Biomarker Detection

5-Hydroxymethylfurfural and Furfural Base-Free Oxidation over AuPd Embedded Bimetallic Nanoparticles

Mechanochemical Strategies for the Preparation of SiO2-Supported AgAu Nanoalloy Catalysts

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