Impact of particle size and metal–support interaction on denitration behavior of well-defined Pt–Cu nanoparticles

Miyazaki, Akane; Matsuda, Kahori; Papa, Florica; Scurtu, Mariana; Negrilǎ, C.; Dobrescu, Gianina; Balint, Ioan

doi:10.1039/c4cy00929k

Cited by 22 publications

(9 citation statements)

References 37 publications

(38 reference statements)

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“…Thus, it was expected that the hydrogen available on the catalyst surface decreases with the indium addition due to the decrease of the accessible surface area of free platinum. Miyazaki et al (2015) reported a nitrite conversion of 31.5% over a 1 wt% Pt/Al 2 O 3 catalyst after 190 min of reaction and only 11.1% of nitrogen selectivity. Selectivities to ammonium higher than 70% were obtained by Yoshinaga et al (2002) and Chinthaginjala and Lefferts (2010) when monometallic palladium catalyst supported on carbon materials were used in nitrite reduction.…”

Section: Resultsmentioning

confidence: 99%

Highly N2-Selective Activated Carbon-Supported Pt-In Catalysts for the Reduction of Nitrites in Water

et al. 2021

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The catalytic reduction of nitrites over Pt-In catalysts supported on activated carbon has been studied in a semi-batch reactor, at room temperature and atmospheric pressure, and using hydrogen as the reducing agent. The influence of the indium content on the activity and selectivity was evaluated. Monometallic Pt catalysts are very active for nitrite reduction, but the addition of up to 1 wt% of indium significantly increases the nitrogen selectivity from 0 to 96%. The decrease in the accessible noble metal surface area reduces the amount of hydrogen available at the catalyst surface, this favoring the combination of nitrogen-containing intermediate molecules to promote the formation of N2 instead of being deeply hydrogenated into NH4+. Several activated carbon-supported Pt-In catalysts, activated under different calcination and reduction temperatures, have been also evaluated in nitrite reduction. The catalyst calcined and reduced at 400°C showed the best performance considering both the activity and the selectivity to nitrogen. This enhanced selectivity is ascribed to the formation of Pt-In alloy. The electronic properties of Pt change upon alloy formation, as it is demonstrated by XPS.

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Section: Resultsmentioning

confidence: 99%

Highly N2-Selective Activated Carbon-Supported Pt-In Catalysts for the Reduction of Nitrites in Water

et al. 2021

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“…The high activity of Ru/C with nitrate observed here in comparison with earlier reports warrants further examination. Several studies have documented that the reactivity of supported metal nanoparticles is influenced by nanoparticle size and shape, chemical state, support properties and metal-support interaction, which are subject to the starting materials (support material and metal precursor), synthesis methods and activation steps [36,78]. The present study used commercially produced catalysts to take advantage of materials with optimized industrial production and adapted for large scale applications.…”

Section: Effect Of Pretreatment On Nitrate Reduction Activitymentioning

confidence: 99%

“…Deposition of a second "promoter" metal (e.g., Cu, In, Sn) together with Pd is typically required to facilitate reduction of nitrate to nitrite [23,31,32]. A large body of literature has reported on aqueous nitrate reduction with Pd-based bimetallic catalysts [20,30,31,[33][34][35][36][37], and our current understanding of metal-catalyzed nitrate hydrogenation mechanisms has been limited to reactions occurring with these materials. The prevailing reaction pathway follows a two-step process depicted in Scheme 1: (1) hydrogenation of nitrate to nitrite on bimetallic clusters followed by (2) further hydrogenation of nitrite on Pd sites to a mixture of N 2 and ammonium stable endproducts, the net processes being reflected by Eqs.…”

Section: Introductionmentioning

confidence: 99%

“…Although years of effort have been invested in improving the activity, endproduct selectivity, and long-term stability of Pd-based bimetallic catalysts [31,45] (and to a lesser extent Pt-based catalysts [36,46]), deployment of practical catalytic treatment systems remains limited, in large part, due to high costs of Pd [47]. Precious metal-free catalysts based on Ni have been explored [15,48,49], but instability in aqueous matrices [50], and serious concerns about the associated leaching of dissolved Ni 2+ [51] and the pyrophoric nature of highly active Raney Ni [52] have limited further development efforts.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogenation of aqueous nitrate and nitrite with ruthenium catalysts

Huo

Hoomissen

Liu

et al. 2017

Applied Catalysis B: Environmental

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Historically, development of catalysts for treatment of nitrate-contaminated water has focused on supported Pd-based catalysts, but high costs of the Pd present a barrier to commercialization. As part of an effort to develop lower cost hydrogenation catalysts for water treatment applications, we investigated catalysts incorporating Ru with lower cost. Pseudo-first-order rate constants and turnover frequencies were determined for carbon-and alumina-supported Ru and demonstrated Ru's high activity for hydrogenation of nitrate at ambient temperature and H 2 pressure. Ex situ gas pretreatment of the catalysts was found to enhance nitrate reduction activity by removing catalyst surface contaminants and exposing highly reducible surface Ru oxides. Ru reduces nitrate selectively to ammonium, and no aqueous nitrite intermediate is observed during reactions. In contrast, reactions initiated with nitrite yield a mixture of two endproducts, with selectivity shifting from ammonium towards N 2 at increasing initial aqueous nitrite concentrations. Experimental observation and Density Functional Theory calculations

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“…Moreover, Epron et al [ 49 ] reported the catalytic reduction of nitrate (

by using Pd/CeO 2 catalyst and highlighted the promoting effect of ceria support based on its redox properties. Several studies have documented that activity of supported metal nanoparticles is influenced by nanoparticle size, metal–support interaction, synthesis method and capping agent [ 50 , 51 , 52 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Nanoparticle Size in Pt/SiO2 Catalyzed Nitrate Reduction in Liquid Phase

et al. 2021

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Effect of platinum nanoparticle size on catalytic reduction of nitrate in liquid phase was examined under ambient conditions by using hydrogen as a reducing agent. For the size effect study, Pt nanoparticles with sizes of 2, 4 and 8 nm were loaded silica support. TEM images of Pt nanoparticles showed that homogeneous morphologies as well as narrow size distributions were achieved during the preparation. All three catalysts showed high activity and were able to reduce nitrate below the recommended limit of 50 mg/L in drinking water. The highest catalytic activity was seen with 8 nm platinum; however, the product selectivity for N2 was highest with 4 nm platinum. In addition, the possibility of PVP capping agent acting as a promoter in the reaction is highlighted.

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Impact of particle size and metal–support interaction on denitration behavior of well-defined Pt–Cu nanoparticles

Abstract: Well-dispersed Pt–Cu nanoparticles with two average sizes were synthesized: small (≈1.6 nm) and large (≈4.8 nm), respectively.

Cited by 22 publications

References 37 publications

Highly N2-Selective Activated Carbon-Supported Pt-In Catalysts for the Reduction of Nitrites in Water

Highly N2-Selective Activated Carbon-Supported Pt-In Catalysts for the Reduction of Nitrites in Water

Hydrogenation of aqueous nitrate and nitrite with ruthenium catalysts

Effect of Nanoparticle Size in Pt/SiO2 Catalyzed Nitrate Reduction in Liquid Phase

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