Experimental and Computational Investigation of Au<sub>25</sub> Clusters and CO<sub>2</sub>: A Unique Interaction and Enhanced Electrocatalytic Activity

Kauffman, Douglas R.; Alfonso, Dominic; Matranga, Christopher; Hu, Qian; Jin, Rongchao

doi:10.1021/ja303259q

Cited by 366 publications

(389 citation statements)

References 59 publications

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“…Likewise, on 5 nm Au/PVDF electrodes the onset is shifted anodically by 60 mV relative to Au foil, while on 5 nm Au/Nafion electrodes the onset is shifted anodically by 140 mV relative to Au foil ( Figure 3). Onset potentials for CO 2 reduction at Au foil (near −0.44 V versus the RHE) and the shift observed with Au/Nafion electrodes are consistent with previous works; 38,39,55 however, the effect of the binder (Nafion versus PVDF) is striking. Reduction current-potential behavior and current densities are similar in each case; note the current associated with composite electrodes is normalized by the geometric area of the glassy carbon.…”

Section: Resultssupporting

confidence: 91%

“…3,37 For example, Jin et al recently demonstrated Au 25 nanoclusters in CO 2 reduction with reduction onset potentials at −0.193 V vs RHE (Relative Hydrogen Electrode) which is approximately 200 mV positive of the onset potential for the same reaction at Au foil electrodes. 38,39 The authors attributed the improvement in performance to the promotion of CO 2 adsorption due to unique associations between the Au 25 and CO 2 . The ability to leverage ligand and size effects to lower CO 2 reduction onset potentials can have profound effects due to the exponential relationship between current and potential (e.g.…”

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confidence: 99%

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Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Andrews

Krishna

Kumar

et al. 2015

J. Electrochem. Soc.

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Nanoscale Au electrocatalysts demonstrate the extraordinary ability to reduce CO 2 at low overpotentials with high selectivity to CO. Here, we investigate the role of surface chemistry on CO 2 reduction behavior using Au 25 and 5 nm Au nanoparticles. Onset potentials for CO 2 reduction at Au 25 nanoparticles in Nafion binders are shifted anodically by 190 mV while the hydrogen evolution reaction is shifted cathodically by 300 mV relative to Au foil. The net effect of this beneficial separation in onset potentials is relatively high Faradayic efficiencies for CO (90% at 0.8 V versus RHE) at high current densities. Experimental results show Faradayic efficiencies for CO are greatest using electrodes made with Nafion-immobilized Au 25 nanoparticles. Likewise, CO 2 reduction onset potential shifts are greater for smaller nanoparticles and when Nafion binders are used instead of (sulfonate-free) polyvinylidene fluoride. X-ray photoelectron spectroscopy analysis reveals Au nanoparticles may react with the sulfonates of Nafion binders. The results suggest sulfonate interfaces may alter the binding energies of key species or lead to favorable reconstructions, either of which ultimately results in remarkable improvements in Faradayic efficiencies relative to Au foil electrodes. The electrochemical reduction of CO 2 holds promise to generate energy-dense fuels using only atmospheric CO 2 , water and solar or wind energy. In recent works, several types of wet-synthesized metal nanoclusters (Au, Ag, Pt, Pd, Cu) have been demonstrated in electrochemical sensors 1-3 or electrolytic cells 3-5 with remarkable advantages over conventional metal (foil) electrodes. Recent works using Au 25 nanoclusters as electrochemical sensors demonstrate nanomolar sensitivity for species such as dopamine, ascorbic acid, uric acid, iodide or nitrites.6-8 Likewise composite electrodes with Au, Ag and Cu nanoclusters have shown desirable current-potential behaviors in CO 2 and O 2 reduction reactions including significantly lower onset potentials relative to their foil analogs (>100 mV). The underlying nature of activity enhancements associated with the structure or surface chemistry of composite nanocluster electrodes is not well established. As with enzymatic mechanisms, it is possible that structural effects associated with the ligated surface may facilitate specific reactant or product interactions. It is also possible that both kinetic and thermodynamic benefits originate from unique properties associated with under-coordinated (or ligated) metal atoms that result in improved binding energies or reduced transition state energies. In general, literature reports suggest decreasing particle dimensions increases catalytic activity; 9,10 however, trends in the electrochemical behavior associated with adsorbed ligands are less clear.11,12 Recent work by Liu et al. 13 shows alkyl-terminated Pt nanoparticles (2.85 nm) exhibit semiconducting behavior while phenyl-terminated Pt nanoparticles of the same size demonstrate metallic behavior and are more a...

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Section: Resultssupporting

confidence: 91%

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confidence: 99%

Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Andrews

Krishna

Kumar

et al. 2015

J. Electrochem. Soc.

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“…Thiolate-protected palladium nanoclusters with a mass of approximately 5 kDa are synthesized by using a one-phase method, and the chemical formula is estimated to be Pd [13][14][15][16][17] (SR) [18][19][20][21][22] . The ultrasmall palladium nanoclusters exhibit excellent performance for the ORR in alkaline solutions.…”

Section: Discussionmentioning

confidence: 99%

Ultrasmall Palladium Nanoclusters as Effective Catalyst for Oxygen Reduction Reaction

et al. 2016

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The recent prosperity of ultrasmall gold nanoclusters makes it desirable to expand the family of clusters to other metals. Here, we present a one‐phase approach for synthesizing thiolate‐protected palladium nanoclusters with a mass of approximately 5 kDa. Such nanoclusters are further evaluated for the oxygen reduction reaction in alkaline solutions. Ligand‐on palladium nanoclusters exhibit an onset potential of −0.09 V (vs. Ag/AgCl) and superior durability in open air. With ligands removed, the palladium nanoclusters display an onset potential of −0.02 V and a higher mass activity (272.4 A g−1 at the potential of −0.15 V) than that of Pt/C (166.6 A g−1). Kinetic investigation indicates a direct four‐electron reduction pathway over palladium nanoclusters, which is preferred in oxygen reduction, owing to enhanced power generation. The efficient catalytic performance of palladium nanoclusters makes them an excellent candidate as electrocatalysts in fuel cell technology.

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“…Small Au 25 clusters experimentally show much better performance than bulk Au particles, and computational data illustrate the banding energy of CO 2 with Au cluster vary from sites to sites 73. For Au particles with different sizes, the ratios of atoms at edges or surface are different.…”

Section: Edges As Active Sitesmentioning

confidence: 93%

Face the Edges: Catalytic Active Sites of Nanomaterials

Wang

2015

Advanced Science

151

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Edges are special sites in nanomaterials. The atoms residing on the edges have different environments compared to those in other parts of a nanomaterial and, therefore, they may have different properties. Here, recent progress in nanomaterial fields is summarized from the viewpoint of the edges. Typically, edge sites in MoS2 or metals, other than surface atoms, can perform as active centers for catalytic reactions, so the method to enhance performance lies in the optimization of the edge structures. The edges of multicomponent interfaces present even more possibilities to enhance the activities of nanomaterials. Nanoframes and ultrathin nanowires have similarities to conventional edges of nanoparticles, the application of which as catalysts can help to reduce the use of costly materials. Looking beyond this, the edge structures of graphene are also essential for their properties. In short, the edge structure can influence many properties of materials.

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Experimental and Computational Investigation of Au₂₅ Clusters and CO₂: A Unique Interaction and Enhanced Electrocatalytic Activity

Cited by 366 publications

References 59 publications

Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Ultrasmall Palladium Nanoclusters as Effective Catalyst for Oxygen Reduction Reaction

Face the Edges: Catalytic Active Sites of Nanomaterials

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Experimental and Computational Investigation of Au25 Clusters and CO2: A Unique Interaction and Enhanced Electrocatalytic Activity

Cited by 366 publications

References 59 publications

Electrocatalytic Reduction of CO2at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Electrocatalytic Reduction of CO2at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Ultrasmall Palladium Nanoclusters as Effective Catalyst for Oxygen Reduction Reaction

Face the Edges: Catalytic Active Sites of Nanomaterials

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Experimental and Computational Investigation of Au₂₅ Clusters and CO₂: A Unique Interaction and Enhanced Electrocatalytic Activity

Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior

Electrocatalytic Reduction of CO₂at Au Nanoparticle Electrodes: Effects of Interfacial Chemistry on Reduction Behavior