Support, composition, and ligand effects in partial oxidation of benzyl alcohol using gold–copper clusters

Brindle, Joseph; Sufyan, Sayed Abu; Nigra, Michael M.

doi:10.1039/d2cy00137c

Cited by 7 publications

(16 citation statements)

References 91 publications

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“…Monometallic ligand-protected Au nanoparticle(s) with TPP are prepared following the published synthetic methods. − The synthesis of TPMT-bound Au nanoparticles is novel to this work. Brief synthetic details are given in this section.…”

Section: Methodsmentioning

confidence: 99%

“…The 0.5 mL aliquots of the reaction mixture were extracted every 30 min for 3 h, and product mixtures were analyzed using a Thermo Scientific Trace 1310 Gas Chromatograph equipped with a Flame Ionization Detector and TraceGOLD TG-624 column. 29 ■ RESULTS AND DISCUSSION Catalyst Synthesis and Characterization. Au nanoparticles are synthesized with bound TPP or TPMT ligands that are shown in Figure 1A.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Electronic Tuning of Gold Nanoparticle Active Sites for Reduction Catalysis

Sufyan

Devener

Perez

et al. 2022

ACS Appl. Mater. Interfaces

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Electronic tuning of active sites in heterogeneous catalysis with organic ligands remains challenging since the ligands are often bound to the most active sites on the catalysts’ surfaces. In this work, gold nanoparticles, which are on average less than 2 nm in diameter, are synthesized with strongly binding thiol and phosphine ligands and have measurable quantities of accessible sites on their surfaces in both cases. Triphenylphosphine (TPP) is used as the phosphine ligand, while triphenylmethyl mercaptan (TPMT) serves as the thiol ligand. Phosphines are chosen because they are electron-donating ligands when bound to Au, and thiols are selected because they are electron-withdrawing on the Au surface. X-ray photoelectron spectroscopy (XPS) results show differences in the Au 4f binding energies between the TPP- and TPMT-bound Au nanoparticles. Fourier transform infrared spectroscopy (FTIR) measurements of bound CO indicate that the TPP-bound Au nanoparticles are more electron-rich than the TPMT-bound Au nanoparticles. The number of binding sites on the surface is quantified using 2-naphthalenethiol titration experiments. It is observed that the number of binding sites on the thiol and phosphine-bound Au nanoparticles is similar in both cases. The Au nanoparticles are used for three different reactions: resazurin reduction, CO oxidation, and benzyl alcohol oxidation. For both CO oxidation and benzyl alcohol oxidation, which are performed with the ligands attached, TPP- and TPMT-bound nanoparticles are both catalytically active. However, for resazurin reduction, the TPMT-bound Au nanoparticles are not active, while the TPP-bound Au nanoparticles are catalytically active. These results illustrate that the catalytic activity can be tuned using bound organic ligands with different electronic properties for reduction reactions using Au nanoparticle catalysts.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Electronic Tuning of Gold Nanoparticle Active Sites for Reduction Catalysis

Sufyan

Devener

Perez

et al. 2022

ACS Appl. Mater. Interfaces

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“…[32][33][34][35] In catalytic applications, AuNPs convert primary alcohol functional groups under alkaline conditions using peroxides to either aldehyde or carboxylic acid groups. [36][37][38][39][40][41] This selective oxidation of alcohols to aldehydes and acids using air as an oxygen source is a desirable catalytic process as it eliminates the need for environmentally harmful oxidizing agents, such as strong acids. 42 The hybrid cascade catalytic system described in this work, glucose oxidase (GOx) with bound gold nanoparticles (AuNP-GOx), combines both the enzymatic functionality of GOx and the oxidative catalytic functionality of the AuNPs.…”

Section: Introductionmentioning

confidence: 99%

“…AuNPs on their own have a propensity to oxidise primary alcohols to acids under alkaline conditions. 26,41 Additionally, the use of glucose oxidase facilitates the conversion of glucose to gluconic acid and H 2 O 2 , providing a mild oxidant (H 2 O 2 ) for the further oxidation of gluconic acid to saccharic acid. The in situ H 2 O 2 generation is beneficial with respect to process safety and cost.…”

Section: Introductionmentioning

confidence: 99%

“…32–35 In catalytic applications, AuNPs convert primary alcohol functional groups under alkaline conditions using peroxides to either aldehyde or carboxylic acid groups. 36–41 This selective oxidation of alcohols to aldehydes and acids using air as an oxygen source is a desirable catalytic process as it eliminates the need for environmentally harmful oxidizing agents, such as strong acids. 42…”

Section: Introductionmentioning

confidence: 99%

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Catalytic cooperativity between glucose oxidase and gold nanoparticles in the sequential oxidation of glucose to saccharic acid

et al. 2022

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Synthesis of Highly Accessible and Reactive Sites in Gold Nanoparticles Using Bound Bis(Diphenylphosphine) Ligands

Sufyan

Devener

Nigra

2022

Chemistry A European J

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While bound organic ligands provide steric protection against aggregation for metallic nanoparticles in solution, they can block a large fraction of the surface atoms which are needed for binding in catalysis and sensing applications. In this work, highly accessible Au nanoparticles ligated with bis(diphenylphosphine) molecules are synthesized and characterized in solution. Characterization is performed using high angle annular dark field‐scanning transmission electron microscopy (HAADF‐STEM), ultraviolet‐visible (UV‐Vis) spectroscopy, and fluorescence chemisorption experiments. These synthesized nanoparticles are accessible to a 2‐napthalenethiol (2‐NT) probe molecule in solution. The highest 2‐NT accessibility is observed when using 1,1‐bis(diphenylphosphino)methane (dppm) ligand where 61 % of the total gold atoms are accessible. It is hypothesized that increasing the rigidity of the bis(diphenylphosphine) ligand increases the number of binding sites on the Au nanoparticles. These nanoparticles are catalytically active for resazurin reduction, and the resazurin reduction rate scales with the number of binding sites.

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Support, composition, and ligand effects in partial oxidation of benzyl alcohol using gold–copper clusters

Abstract: The application of gold bimetallic nanoparticles and clusters in oxidation catalysis has produced many advances in performance over their monometallic gold counterparts. In this work, triphenylphosphine(TPP)-bound gold-copper alloy clusters are...

Cited by 7 publications

References 91 publications

Electronic Tuning of Gold Nanoparticle Active Sites for Reduction Catalysis

Electronic Tuning of Gold Nanoparticle Active Sites for Reduction Catalysis

Catalytic cooperativity between glucose oxidase and gold nanoparticles in the sequential oxidation of glucose to saccharic acid

Synthesis of Highly Accessible and Reactive Sites in Gold Nanoparticles Using Bound Bis(Diphenylphosphine) Ligands

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