Effect of Particle Restructuring During Reduction Processes Over Polydopamine-Supported Pd Nanoparticles

Gazdag, Tamás; Baróthi, Ádám; Juhász, Koppány Levente; Kunfi, Attila; Németh, Péter; Sápi, András; Kukovecz, Ákos; Szőori, Kornél; London, Gábor

doi:10.1166/jnn.2019.15770

Cited by 6 publications

(3 citation statements)

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“…In nanocatalysis, in addition to the metal NPs, semiconductors can be used as supports in order to avoid NP aggregation, facilitate catalyst recovery, provide additional catalytic sites due to metal–support interactions, and facilitate the interaction or activation of substrates or intermediates. − However, to our knowledge, few works mentioned the metal–semiconductor heterojunction interactions towards thermal catalysis. Similar to photocatalysis, it has been established in thermal catalysis that semiconductors can contribute to prolong the lifetimes of thermally excited carriers, and potentially boost their catalytic properties …”

Section: Introductionmentioning

confidence: 99%

Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Liu

Wang

et al. 2019

ACS Appl. Mater. Interfaces

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Sodium (Na)- and potassium (K)-doped δ-MnO2, which presented different band gaps, were synthesized by a hydrothermal method. Then, uniform Au nanoparticles (NPs) were deposited on MnO2 to form metal–semiconductor nano-heterojunctions (MnO2–Au). By comparing their temperature-dependent thermal catalytic performances, p-aminothiophenol to p,p′-dimercaptoazobenzene conversion was used as proof-of-concept transformations. MnO2–Au hybrid materials demonstrated better thermal catalytic performances relative to individual Au NPs. Meanwhile, K-doped MnO2–Au, with a MnO2 support displaying a narrower bandgap, displayed superior catalytic activities relative to Na-doped MnO2–Au. To get the same catalytic performance by individual Au NPs, it can be ∼50 K less by Na-doped MnO2–Au and ∼100 K less by K-doped MnO2–Au. The enhancement is mainly attributed to the thermally excited electrons in MnO2, which were transferred to Au NPs. The additional electrons in Au NPs increase the electron density and thus contribute to the improvement of thermal catalysis. Our findings show that the establishment of a nano-heterojunction formed by metal NPs on a semiconductor support has a significant impact on thermal catalysis, where a narrower band gap can facilitate thermally excited carriers and thus bring about better catalytic performances. Thus, the results presented here shed light on the design of a nano-heterojunction catalyst to approach reactions with superior performance under moderate conditions.

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Section: Introductionmentioning

confidence: 99%

Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Liu

Wang

et al. 2019

ACS Appl. Mater. Interfaces

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“…observed earlier the aggregation of Pd particles when using a 3.03 % Pd 0 ‐PDA catalyst in transfer hydrogenation . Subsequently, they studied the phenomenon in detail . In the hydrogenation of ethyl 4‐nitrobenzoate (0.57 mol% Pd 0 ‐PDA, HCOONa, ethanol, 85 °C) increases in the Pd particle size (1–3 nm) were observed under varied conditions with the concomitant decreases in product yields.…”

Section: Organic Synthesismentioning

confidence: 95%

Polydopamine – its Prolific Use as Catalyst and Support Material

Molnár

2020

ChemCatChem

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Polydopamine is a mussel-inspired functional material with a unique ability to form surface coatings. It is a green, environmentally benign product available very easily for a multitude of varied applications. This review attempts to collect useful information with respect to polydopamine-based catalytic studies with the use of polydopamine and modified polydopamine preparations loaded with varied catalytically active species including metal ions and metal particles. Major sections are about the use of polydopamine as catalyst material, utilization of immobilized enzymes, removal of toxic materials, results in organic synthesis, and fuel cell applications. A few examples of chiral catalysis and results of recycling studies are also treated. Data collected and analyzed indicate the importance and high potential of polydopamine-based catalysts in sustainable chemistry. of subunits attacked by an immobilized cyclohexeneamine (5) was suggested to be the transition state of CÀ C bond formation.Edouard et al. prepared catalyst 0.29 % PDA/PU by depositing PDA onto polyurethane foam (PU, 180 � 20 mg, 8 cm 3 ) and used it for the reduction of methylene blue (MB) with NaBH 4 . [48] Activities decreased gradually with repeated uses from 100 % to 35 % in run 11 but partial reactivation was achieved upon keeping the sample at 67°C for 8 h (55 % dropping below 10 % in run 13). Exposure to air at room temperature for six days proved to be somewhat more beneficial (90 % conversion in run 14 decreasing to 48 % in run 18). In a recent study they fabricated two oxidized PDA/PU samples and then loaded them with NaBH 4 . [49] One made by the usual method (dopamine/Tris, rt, 12 h, in air; sample PDA O2 PU), whereas the other was made by treating PU in a mixture of dopamine, NaOAc, and NaIO 4 (pH 5, rt, 24 h). The sample was dried (67°C) and washed thoroughly with water (PDA NaIO4 PU). Both products were dipped into an aqueous solution of NaBH 4 (0.1 M, 10 min) to afford boron contents of 2.37 and 2.11 wt%. The catalysts tested in the degradation of MB showed high activities with efficiencies of 97 % and 98 %, respectively (NaBH 4 /MB molar ratio 40, 177 mg and 209 mg catalysts, 25 min). During five reuses, the pH of the reaction medium increased because of boron loss (0.78 wt% and 0.81 wt%). The activity of PDA NaIO4 PU decreased to 89 % in run five. However, dipping the used sample into a 0.1 M NaBH 4 solution restored the original efficiency of 98 %. This, however, was only a temporary remedy, since a low efficiency of 60 % was measured in run 10. PDA was suggested by the authors to act as a redox mediator to prevent the hydrolysis/oxidation of immobilized borohydride.This formula (5) should be moved up and placed before the paragraph starting with "Edouard et al…"The Zuo group used PDA particles (avg. diameter 240 nm) to induce the reduction of MB and rhodamine B (RhB) with NaBH 4 . [50] Quinone moieties of PDA were assumed to channel electrons from NaBH 4 to the dyes. Indeed, PDA oxidized with NaIO 4 exhibited increased degradatio...

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“…It is well known that smaller sized Pd species is beneficial to better catalytic efficiency. [30][31][32] Therefore, a high-efficiency preparation method to derive high porous carbon supported Pd catalytic materials with excellent active species dispersion is still desired.…”

Section: Introductionmentioning

confidence: 99%

Porous carbon supported Pd catalysts derived from gelatin‐based/chitosan or polyvinyl pyrrolidone/PdCl₂ blends

Huang

Yang

Chen

et al. 2022

J of Applied Polymer Sci

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Novel N-containing porous carbon supported Pd heterogeneous catalysts have been derived by carbonization of gelatin (GEL)/chitosan/PdCl 2 (GEL/CS/ PdCl 2 ) and GEL/polyvinyl pyrrolidone/PdCl 2 (GEL/PVP/PdCl 2 ) blends under N 2 atmosphere at 800 C. The microstructure of the resultant N-containing carbon supported Pd heterogeneous catalysts can be tailored by the nature of the blended polymers. Much larger specific surface area, better dispersion of Pd 0 /PdO nanoparticles, higher Pd and N contents are found in the case of N-containing porous carbon supported Pd heterogeneous catalysts derived from GEL/CS/PdCl 2 blend system. When the mass ratio of GEL to CS is kept at 1/1, the surface area of 644.8 m 2 /g, rich porous structure, N % of 7.2%, and Pd 0 /PdO nanoparticles sized below 3 nm are obtained in the derived Pd@N-C-GEL/CS(1/1) catalyst. It shows excellent catalytic efficiency (higher than 90%) in Heck coupling reaction of aromatic halides and alkenes, and high recycling stabilities both in aqueous (9 runs) and organic (15 runs) phase. The high activity and stability of the novel Pd@N-C-GEL/CS(1/1) catalyst have been attributed to a combination of high porous structure, strong chelation of Pd species, high thermal stability, and good solvent-resistant performances.

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Effect of Particle Restructuring During Reduction Processes Over Polydopamine-Supported Pd Nanoparticles

Cited by 6 publications

References 0 publications

Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Polydopamine – its Prolific Use as Catalyst and Support Material

Porous carbon supported Pd catalysts derived from gelatin‐based/chitosan or polyvinyl pyrrolidone/PdCl₂ blends

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Effect of Particle Restructuring During Reduction Processes Over Polydopamine-Supported Pd Nanoparticles

Cited by 6 publications

References 0 publications

Tuning Thermal Catalytic Enhancement in Doped MnO2–Au Nano-Heterojunctions

Tuning Thermal Catalytic Enhancement in Doped MnO2–Au Nano-Heterojunctions

Polydopamine – its Prolific Use as Catalyst and Support Material

Porous carbon supported Pd catalysts derived from gelatin‐based/chitosan or polyvinyl pyrrolidone/PdCl2 blends

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Product

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Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Tuning Thermal Catalytic Enhancement in Doped MnO₂–Au Nano-Heterojunctions

Porous carbon supported Pd catalysts derived from gelatin‐based/chitosan or polyvinyl pyrrolidone/PdCl₂ blends