Complex PtPdRh nanoparticles: Synthesis, characterization, and performance in the electrocatalytic oxidation of ammonia

Júlio César Martins Silva)Highlights Direct ammonia fuel cell (DAFC) performance using PtRh/C electrocatalysts as anode.Ammonia oxidation evaluation by electrochemical experiments. An optimization study of the NH 4 OH and KOH concentrations used as fuel in a DAFC.Using PtRh/C 90:10 were obtained the highest power density and open circuit voltage.Using 3 mol L -1 KOH and 3 mol L -1 NH 4 OH the best result in a DAFC was obtained. AbstractThis study reports on the use of PtRh/C electrocatalysts prepared by the borohydride reduction method with different Pt:Rh atomic ratios: (90:10, 70:30 and 50:50) which was investigated toward the ammonia electro-oxidation considering electrochemical and also direct ammonia fuel cell (DAFC) experiments. The DAFC experiments were conducted using different proportions of NH 4 OH and KOH as fuels.X-ray diffraction showed the formation of PtRh alloy while transmission electron micrographs showed the particles sizes between 4.1 and 4.5 nm. Among the different NH 4 OH and KOH concentrations the combination of 3 mol L -1 NH 4 OH and 3 mol L -1 KOH was the most favorable due to the higher KOH concentration, which increased the electrolyte conductivity, thus improving the ammonia oxidation. Moreover, among the PtRh/C electrocatalysts the Pt:Rh ratio of 90:10 showed to be the best suited one since it showed a power density almost 60 % higher than Pt. X-ray photoelectron spectroscopy results revealed for this catalyst that the nanoparticles contain a high proportion of metallic Pt and Rh phases, supporting the alloy formation between Pt and Rh. The improved fuel cell efficiency can be related to the combination of different effects: the alloy formation between Pt and Rh (electronic effect), suppressing the adsorption strength of poisonous intermediates, and a synergic effect between Pt and Rh at this composition.

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“…However, until now the Pt group metals show the most promising catalytic activity toward this reaction [8,[11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Normally the formation of N ads causes the poisoning of the Pt surface because the adsorption energy of N ads on Pt is relatively high [17]. Then, in order to improve Pt electrocatalytic performance of ammonia oxidation the use of platinum-based binary catalysts is an attractive alternative [8,[11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of ammonia using PtRh/C electrocatalysts: Fuel cell and electrochemical evaluation

Assumpção

Piasentin

Hammer

et al. 2015

Applied Catalysis B: Environmental

103

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“…Until now, PtPdRh-based multimetallic catalysts are widely employed in industry despite their extremely high cost . Nevertheless, up to 800 °C of reaction temperature is required to promote the yield of NO x , resulting in the degradation of catalysts at such high temperature. , Besides, the synthesis of solid-solution of PtPdRh multimetallic system is difficult owing to the immiscibility. Yao and his co-worker successfully applied PtPdRhRuCe HEA NPs into AOR to achieve remarkable activity, selectivity, and stability (Figure ).…”

Section: Catalysis Of Heasmentioning

confidence: 99%

High-Entropy Alloys as a Platform for Catalysis: Progress, Challenges, and Opportunities

Yue¹,

Li²,

Qian³

et al. 2020

ACS Catal.

500

282

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High-entropy alloys (HEAs), which are defined as near-equimolar alloys of five or more elements, are attracting ever increasing attention because of the unique properties in a variety of applications. Recently, HEAs have already exhibited remarkable catalytic performance toward several thermal-driven and electrocatalytic reactions. HEAs not only regulate the electronic and geometric structures to a large degree but also serve as a platform to construct catalysts with unexpected performance. Herein, recent advances regarding HEA-based catalysis are systematically summarized, with a special focus on the synthetic methods for HEA-based catalysts, catalytic performance, and mechanistic understanding. Moreover, the challenges and future opportunities for this research area are carefully discussed. A series of open questions and promising directions to be explored are proposed, including synthetic methods, regulation of electronic properties, identification of active centers, and applications into photocatalysis. This Review provides an overview about the progress, challenges, and opportunities for HEA-based catalysis.

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“…Pt [1][2][3], Au [1,4,5], and Ag [6][7][8] are the main noble metals used in noble metal catalyst. It is well-known that Pt could exhibit an excellent catalytic activity for various oxidation reactions including propylene epoxidation, CO oxidation, and hydrocarbon methanol oxidation reaction [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

A highly reactive and enhanced thermal stability nanocomposite catalyst based on Pt nanoparticles assembled in the inner surface of mesoporous SiO2 spherical shell

et al. 2015

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Complex PtPdRh nanoparticles: Synthesis, characterization, and performance in the electrocatalytic oxidation of ammonia

Cited by 11 publications

References 42 publications

Oxidation of ammonia using PtRh/C electrocatalysts: Fuel cell and electrochemical evaluation

Oxidation of ammonia using PtRh/C electrocatalysts: Fuel cell and electrochemical evaluation

High-Entropy Alloys as a Platform for Catalysis: Progress, Challenges, and Opportunities

A highly reactive and enhanced thermal stability nanocomposite catalyst based on Pt nanoparticles assembled in the inner surface of mesoporous SiO2 spherical shell

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