Promotional effects of ethylenediamine on the low-temperature catalytic activity of selective catalytic oxidation of ammonia over Pt/SiAlOx: States and particle sizes of Pt

Liu, Jingying; Sun, Mengmeng; Lin, Qingjin; Liu, Shuang; Xu, Haidi

doi:10.1016/j.apsusc.2019.03.199

Cited by 28 publications

(14 citation statements)

References 48 publications

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“…In another study, EDA was utilized as an electron donor to enhance the conversion of PtO x to active Pt 0 species and therefore make the Pt NPs electron-rich. The increased amount of Pt 0 species improved the low-temperature selective catalytic oxidation of ammonia . A comprehensive study on adapting ligands with different electron-donating abilities also confirmed the above conclusion: the more electron-rich the NP surface is, the easier it is for electron-deficient reactants to be adsorbed .…”

Section: The Beneficial Effects Of Ligands For Nanocatalysissupporting

confidence: 59%

“…The increased amount of Pt 0 species improved the low-temperature selective catalytic oxidation of ammonia. 196 A comprehensive study on adapting ligands with different electron-donating abilities also confirmed the above conclusion: the more electron-rich the NP surface is, the easier it is for electron-deficient reactants to be adsorbed. 197 Phosphorus-based ligands (tricyclohexylphosphine, PCy 3 and triphenylphosphine, PPh 3 ) were applied to tune the electronic properties of the NP surface.…”

Section: The Beneficial Effects Of Ligands For Nanocatalysismentioning

confidence: 55%

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The Critical Impacts of Ligands on Heterogeneous Nanocatalysis: A Review

2021

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Ligand utilization is a necessary and powerful technique for the colloidal synthesis of nanoparticles (NPs) with controllable sizes and regulated morphologies. For catalysis applications, it is commonly believed that surface ligands on metal NPs block the active catalytic sites and reduce the catalytic activity. Nevertheless, since 2010, an increasing number of research groups have demonstrated the unexpected benefits of ligands that improve catalytic activity and/or selectivity. These benefits can be ascribed to the construction of an inorganic−organic interface, through which a series of factors, such as steric, electronic, and solubility effects, can be utilized to produce favorable changes to the interfacial environment. Considering the tremendous number of developments in this emerging research field, it is necessary to compile a comprehensive and systematic overview of recent advances. In this Review, we summarize the critical impacts of ligands on heterogeneous nanocatalysis. First, we introduce the vital roles of ligands in colloid syntheses for controllable sizes and regulated shapes. Second, the detrimental effects of ligands for nanocatalysis are described on the basis of traditional views. Third, a series of strategies for ligand removal are reviewed and compared. Fourth, on the basis of research that has been conducted in the past decade, the three main beneficial ligand effects (steric, electronic, and solubility) on heterogeneous nanocatalysis are classified and discussed. For each effect, the possible corresponding beneficial mechanism is presented, and typical examples are provided. Recent advances regarding density functional theory (DFT) calculations and the regulation of ligand surface coverage have been dedicated to explaining the ligand-promotion mechanism in nanocatalysis and searching for optimal nanocatalysts. Fifth, the stabilities of cutting-edge ligand-capped nanocatalysts before and after catalytic reactions are discussed. Finally, we highlight the remaining challenges and propose future perspectives. Although much progress has been achieved, the impacts of ligands on the catalytic activities of nanocatalysts are multifaceted and still debatable. We hope this Review will deepen readers' understanding of the actual impacts ligands have on heterogeneous catalysis.

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Section: The Beneficial Effects Of Ligands For Nanocatalysissupporting

confidence: 59%

Section: The Beneficial Effects Of Ligands For Nanocatalysismentioning

confidence: 55%

The Critical Impacts of Ligands on Heterogeneous Nanocatalysis: A Review

2021

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“…The Pt of these catalysts mainly existed in the form of reduced Pt. In addition, the peak intensity of Pt/Al-NKM-5-5 is higher than that of Pt/NKM-5, which demonstrates that the Pt/Al-NKM-5-5 catalyst had a higher dispersity of Pt species …”

Section: Resultsmentioning

confidence: 94%

“…In addition, the peak intensity of Pt/Al-NKM-5-5 is higher than that of Pt/NKM-5, which demonstrates that the Pt/Al-NKM-5-5 catalyst had a higher dispersity of Pt species. 61 Through the acidity test and the Pt particle size analysis, the results showed that as the Al content increased, the acidity of the samples increased gradually. The acidity has an electronwithdrawing ability; the stronger the acidity, the stronger the electron-withdrawing ability, and the stronger the ability to attract PtCl 6 2− , which would play the role of separation and make Pt particle size more even during the reduction process.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Platinum Nanoparticles Supported on Hierarchically Porous Aluminosilicate Nanospheres for Low-Temperature Catalytic Combustion of Volatile Organic Compounds

Chen

Wang

et al. 2020

ACS Appl. Nano Mater.

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The hierarchically porous silica (NKM-5) and aluminosilicate (Al-NKM-5) supported platinum nanoparticles catalysts were prepared and investigated for the catalytic combustion of toluene and ethanol. The Pt/NKM-5 and Pt/Al-NKM-5 catalysts displayed the submicrometer spherical morphology and the hierarchical pore structure, and the Pt nanoparticles were uniformly distributed. The Pt/NKM-5 and Pt/Al-NKM-5 showed excellent low-temperature catalytic activity and CO2 selectivity, and the hierarchical pores were beneficial to the catalytic combustion of toluene. With the increase of Al content, the catalytic activity of Pt/Al-NKM-5 increased gradually; the Pt/Al-NKM-5-5 catalyst with Si/Al = 5 showed the most excellent catalytic activity with 90% toluene conversion at 146 °C and 90% ethanol conversion at 138 °C. The NMR and NH3-TPD showed that the incorporation of Al could increase the acidity of support, which could promote the distribution of Pt and the adsorption of toluene as characterized by UV–vis, TEM, CO pulse chemisorption, and FTIR. The excellent catalytic activity of Pt/Al-NKM-5-5 could be ascribed to the hierarchically porous structure, more acidic sites, and higher Pt dispersity.

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“…The dispersion of Pt species was increased after the introduction of ethylenediamine (from 2.8 to 2.0 nm) during the preparation of (1 wt.%)Pt/SiO 2 -Al 2 O 3 [35], and thus lead to higher activity in NH 3 -SCO in the presence of CO 2 and H 2 O, compared to that of unmodified samples. The N 2 selectivity remained nearly unaffected by the Pt particle size.…”

Section: Pt-and Pd-based Catalystsmentioning

confidence: 99%

Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

Jabłońska

2021

Molecules

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A recent development for selective ammonia oxidation into nitrogen and water vapor (NH3-SCO) over noble metal-based catalysts is covered in the mini-review. As ammonia (NH3) can harm human health and the environment, it led to stringent regulations by environmental agencies around the world. With the enforcement of the Euro VI emission standards, in which a limitation for NH3 emissions is proposed, NH3 emissions are becoming more and more of a concern. Noble metal-based catalysts (i.e., in the metallic form, noble metals supported on metal oxides or ion-exchanged zeolites, etc.) were rapidly found to possess high catalytic activity for NH3 oxidation at low temperatures. Thus, a comprehensive discussion of property-activity correlations of the noble-based catalysts, including Pt-, Pd-, Ag- and Au-, Ru-based catalysts is given. Furthermore, due to the relatively narrow operating temperature window of full NH3 conversion, high selectivity to N2O and NOx as well as high costs of noble metal-based catalysts, recent developments are aimed at combining the advantages of noble metals and transition metals. Thus, also a brief overview is provided about the design of the bifunctional catalysts (i.e., as dual-layer catalysts, mixed form (mechanical mixture), hybrid catalysts having dual-layer and mixed catalysts, core-shell structure, etc.). Finally, the general conclusions together with a discussion of promising research directions are provided.

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Promotional effects of ethylenediamine on the low-temperature catalytic activity of selective catalytic oxidation of ammonia over Pt/SiAlOx: States and particle sizes of Pt

Cited by 28 publications

References 48 publications

The Critical Impacts of Ligands on Heterogeneous Nanocatalysis: A Review

The Critical Impacts of Ligands on Heterogeneous Nanocatalysis: A Review

Platinum Nanoparticles Supported on Hierarchically Porous Aluminosilicate Nanospheres for Low-Temperature Catalytic Combustion of Volatile Organic Compounds

Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

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