Electrochemical Synthesis and Electrocatalytic Properties of Au@Pt Dendrimer-Encapsulated Nanoparticles

Yancey, David F.; Carino, Emily V.; Crooks, Richard M.

doi:10.1021/ja104677z

Cited by 138 publications

(161 citation statements)

References 18 publications

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“…Yancey et al electrochemically synthesized Au@Pt dendrimer-encapsulated nanoparticles and discovered that Au 147 @Pt DENs (dendrimer encapsulated nanoparticles) exhibited higher ORR activity than Au and Pt nanoparticles alone [89].…”

Section: Alloyed Noble Metal Clusters For Orrmentioning

confidence: 99%

Oxygen Reduction Reaction Catalyzed by Noble Metal Clusters

Tang

Wang

2018

Catalysts

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Highly-efficient catalysts for the oxygen reduction reaction (ORR) have been extensively investigated for the development of proton exchange membrane fuel cells (PEMFCs). The state-ofthe-art Pt/C catalysts suffer from high price, limited accessibility of Pt, sluggish reaction kinetics, as well as undesirable long-term durability. Engineering ultra-small noble metal clusters with high surface-to-volume ratios and robust stabilities for ORR represents a new avenue. After a simple introduction regarding the significance of ORR and the recent development of noble metal clusters, the general ORR mechanism in both acidic and basic media is firstly discussed. Subsequently, we will summarize the recent efforts employing Pt, Au, Ag, Pd and Ru clusters, as well as the alloyed bi-metallic clusters for acquiring highly efficient catalysts to enhance both the activity and stability of ORR. Molecular noble metal clusters with definitive composition to reveal the relevant ORR mechanism will be particularly highlighted. Finally, the current challenges, the future outlook, as well as the perspectives in this booming field will be proposed, featuring the great opportunities and potentials to engineering noble metal clusters as highly-efficient and durable cathodic catalysts for fuel cell applications.

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Section: Alloyed Noble Metal Clusters For Orrmentioning

confidence: 99%

Oxygen Reduction Reaction Catalyzed by Noble Metal Clusters

Tang

Wang

2018

Catalysts

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“…While the onset potential (E on ) for the Cu 2+ reduction on mp-TiO 2 /FTO is +0.24 V, the E on value for Au/mp-TiO 2 /FTO shifts to +0.38 V with a weak shoulder around +0.14 V. The peak can be assignable to the underpotential deposition (UPD) of Cu on Au NP surface. [30][31][32] The UPD-Cu layers on Au should be thermodynamically more stable than the surface Cu layer of Cu NPs, which rationalizes the resistant of Cu shell on Au NPs to the aerobic oxidation. Further, photochronopotentiometry (PCP) measurements were carried out.…”

Section: -2mentioning

confidence: 99%

A new bimetallic plasmonic photocatalyst consisting of gold(core)-copper(shell) nanoparticle and titanium(IV) oxide support

2015

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Ultrathin Cu layers (∼2 atomic layers) have been selectively formed on the Au surfaces of Au nanoparticle-loaded rutile TiO2 (Au@Cu/TiO2) by a deposition precipitation-photodeposition technique. Cyclic voltammetry and photochronopotentiometry measurements indicate that the reaction proceeds via the underpotential deposition. The ultrathin Cu shell drastically increases the activity of Au/TiO2 for the selective oxidation of amines to the corresponding aldehydes under visible-light irradiation (λ > 430 nm). Photochronoamperometry measurements strongly suggest that the striking Cu shell effect stems from the enhancement of the charge separation in the localized surface plasmon resonance-excited Au/TiO2.

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“…We previously showed that Pt and Au DENs are catalytic for the ORR. 26,27 Moreover, it has been shown that PAMAM dendrimers terminated with hydroxl groups form dense films on ITO surfaces. 28 It should be noted that the onset of cathodic current on these ITO films has been attributed to partial reduction of surface metal oxides followed by either H + reduction or further reduction of the metal oxides.…”

Section: * S Supporting Informationmentioning

confidence: 99%

Bipolar Electrodes for Rapid Screening of Electrocatalysts

2011

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We report a method for rapid screening of arrays of electrocatalyst candidates. The approach is based on simultaneous activation of the oxygen reduction reaction (ORR) and Ag electrodissolution at the cathodic and anodic poles, respectively, of bipolar electrodes (BPEs). Because the electrochemical activity of the two poles is directly coupled via the BPE, the extent of Ag electrodissolution is directly related to the ORR activity. The screening process lasts ∼12 min. Because Ag dissolution provides a permanent record of catalyst activity, the screening results can be determined by simple optical microscopy after the electrochemical experiment. The method has the potential to provide quantitative information about electrocatalyst activity.H ere we report a new and potentially powerful method for rapid screening of electrocatalysts. The principle is illustrated in Scheme 1, with specific reference to evaluation of the activity of electrocatalysts for the oxygen reduction reaction (ORR). The top frame of Scheme 1a shows an array of three bipolar electrodes (BPEs). 1 The ORR electrocatalyst candidates are deposited onto the cathodic poles of the BPEs, while the anodic poles are composed of parallel Ag microband electrodes. The Ag microbands of each electrode are in electrical contact with one another and with the ORR catalyst via an underlying indium-doped tin oxide (ITO) contact. When a sufficiently high potential (E tot , Scheme 1b) is applied to the solution in the fluidic channel via a pair of driving electrodes, the ORR proceeds at the cathodic poles and the Ag microbands undergo electrodissolution. 2 The efficiency of the ORR catalyst is then determined by counting the number of dissolved Ag microband electrodes: the more bands that dissolve, the better the catalyst. In fact, as we will show, there is a direct thermodynamic link between the overpotential required for the ORR (Scheme 1c) and the number of Ag microbands remaining after the experiment (Scheme 1a). Although we demonstrate this screening method using just three BPEs, arrays of arbitrary size can be monitored in this way with very little additional technological overhead. This is because it is not necessary to make a direct electrical connection to each electrode, which is an intrinsic property of BPEs and the principal reason for using them in an array format. 3 The basic operating principles of BPEs, along with many interesting applications, have been previously described in the scientific literature. 1−14 A driving voltage E tot applied across a microchannel containing a conductive electrolyte solution (Scheme 1b) is dropped nearly linearly over the length of the microchannel. 6 If a conductive wire of sufficient length is present in the microchannel, it will function as a BPE. 1 Specifically, when the interfacial potential differences between the poles of the BPE and the electrolyte solution (ΔE elec , Scheme 1a) are sufficiently high, faradaic processes occur simultaneously: a reduction at the cathodic pole and an oxidation at the a...

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Electrochemical Synthesis and Electrocatalytic Properties of Au@Pt Dendrimer-Encapsulated Nanoparticles

Cited by 138 publications

References 18 publications

Oxygen Reduction Reaction Catalyzed by Noble Metal Clusters

Oxygen Reduction Reaction Catalyzed by Noble Metal Clusters

A new bimetallic plasmonic photocatalyst consisting of gold(core)-copper(shell) nanoparticle and titanium(IV) oxide support

Bipolar Electrodes for Rapid Screening of Electrocatalysts

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