Iridium and IrOx nanoparticles: an overview and review of syntheses and applications

Quinson, Jonathan

doi:10.1016/j.cis.2022.102643

Cited by 42 publications

(51 citation statements)

References 213 publications

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“…(iii) Several synthetic protocols are well documented to obtain in a relatively simple way various nanomaterials in most modern research laboratories. [11][12][13][14][15] (iv) The production methods of precious metal NPs are increasingly developed to respect most of the principles of environment-friendly and sustainable chemistry that are increasingly driving both academic and industrial research. 16 These latest developments are likely to facilitate bridging the gap between academia and industry.…”

Section: Introductionmentioning

confidence: 99%

“…The colloidal production of nanomaterials is indeed a routine approach in many laboratories over the world. 8,11,14,15 The field of catalysis certainly already largely benefited, and still benefits, from colloidal syntheses of nanomaterials, as it has been extensively highlighted in recent work. 2,8,10,19,20 A deeper insight into size, shape, This review proposes a definition to surfactant-free syntheses, highlights established and emerging surfactant-free colloidal syntheses that offer several benefits over more conventional colloidal strategies to develop precious metal NPs, with direct relevance to study and optimize precious metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Surfactant-free colloidal syntheses of precious metal nanoparticles for improved catalysts

Quinson

Kunz²,

Arenz

2022

Preprint

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Colloidal syntheses of nanomaterials offer multiple benefits to study, understand and optimize un-supported and supported catalysts. In particular, colloidal syntheses are relevant to synthetize (precious) metal nanoparticles. By separating the synthesis of the active phase nanoparticles from supporting steps, a deeper knowledge and a rational control on supported catalyst properties is gained. The effect of nanoparticle size, shape, composition, nature of support or metal loading on a support can be studied in more systematic ways. The fundamental knowledge gained paves the way for catalyst optimization by tuning the catalyst activity, selectivity, and stability. However, a major drawback is that most colloidal syntheses require the use of additives or surfactants, which are detrimental to most catalytic reactions since they typically block catalyst active sites. Surfactant removal typically adds complexity, can introduce a lack of reproducibility, is energy consuming, generates waste, and prevents the full exploitation of the many benefits of colloidal syntheses for catalysis. Several surfactant-free strategies to obtain stable colloidal nanoparticles are here reviewed. A focus is given to laser synthesis and processing of colloids (LSPC), solution plasma process (SPP), N,N-dimethylformamide (DMF), polyols, and recently reported mono-alcohols based syntheses. The relevance of these synthetic approaches for catalysis is detailed with a focus on heterogeneous catalysis and electro-catalysis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surfactant-free colloidal syntheses of precious metal nanoparticles for improved catalysts

Quinson

Kunz²,

Arenz

2022

Preprint

Self Cite

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“…6,15 For other systems such as iridium (Ir) NPs, there is a lack of understanding of the formation at the molecular and atomic level. 21 This is at first surprising for two reasons. Firstly, Ir is a relevant material for multiple applications, 21,22 including heterogeneous catalysis.…”

Section: Introductionmentioning

confidence: 99%

“…21 This is at first surprising for two reasons. Firstly, Ir is a relevant material for multiple applications, 21,22 including heterogeneous catalysis. 23,24 Ir has also found applications in sensing 25 or medicine, 26,27 both as monoatomic, or within multimetallic materials.…”

Section: Introductionmentioning

confidence: 99%

“…23,24 Ir has also found applications in sensing 25 or medicine, 26,27 both as monoatomic, or within multimetallic materials. 21 Ir NPs are also increasingly studied for energy conversion, in particular as catalyst for the oxygen evolution reaction. 21,25,28 Secondly, Ir NPs have been a model system used for development of kinetic models of nanomaterial formation.…”

Section: Introductionmentioning

confidence: 99%

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Chemical insights on the formation of colloidal iridium nanoparticles from in situ X-ray total scattering: Influence of precursors and cati-ons on the reaction pathway

Mathiesen

Quinson

Blaseio

et al. 2022

Preprint

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Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of Ir na-noparticles have also been key for the development of kinetic models of nanomaterial formation. However, compared to other metals such as gold or platinum, there is very limited knowledge on the actual formation mechanism of iridi-um nanoparticles on the atomic and molecular level. Here, we use in situ X-ray total scattering experiments with pair distribution function analysis to study a simple, surfactant-free synthesis of colloidal iridium nanoparticles. The reac-tion is performed in methanol at 50 °C with only an iridium salt and a base as precursor. From different precursor salts - IrCl3, IrCl4, H2IrCl6, or Na2IrCl6 –colloidal nanoparticles as small as Ir55 are obtained. The nanoparticles do not show the bulk Ir face centered cubic (fcc) structure, but decahedral and icosahedral structures. Surprisingly, the for-mation mechanism is highly dependent on the precursor salt used. Using IrCl3 or IrCl4, metallic iridium nanoparticles form rapidly from IrxCly complexes, whereas using H2IrCl6 or Na2IrCl6, the iridium nanoparticle formation follows a sudden growth after an induction period and the brief appearance of a crystalline intermediate. With H2IrCl6, the formation mechanism depends on the nature of the cation in the base - LiOH, NaOH, KOH, or CsOH - and larger parti-cles are obtained with larger cations. As the particles grow, the nanoparticle structure changes from partly icosahedral to decahedral. The presented results introduce a new iridium nanoparticle synthesis model system and provide new chemical insights into nanoparticle formation and growth.

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Agglomerate Engineering to Boost PEM Water Electrolyzer Performance

Zhao,

Yuan,

Cheng

et al. 2024

Advanced Energy Materials

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Densely packed IrOx‐ionomer agglomerates play a crucial role in the high mass transport resistance inside the anode catalyst layer (ACL), which in turn greatly affects the electrolysis performance at high current density. Therefore, agglomerate engineering for PEMWE is proposed in this work to enhance the oxygen transport process inside ACLs. Using self‐assembling nanotechnology, tightly packed primary aggregates are avoided and introduce the interconnected submicron pores and nanocavities into the catalyst‐ionomer agglomerate, confirmed by synchrotron radiation‐based nano‐CT, TEM, and BET. Such agglomerate engineering results in the enhancement of both dissolved oxygen and oxygen bubble transport inside the ACL confirmed by RDE tests and in‐situ bubble visualization. As a result, the mass transport overpotential is significantly reduced from 330 to 30 mV at 5 A cm−2 in PEMWE, optimized Ohmic resistance and catalyst utilization are also observed. Finally, high operating current density is achieved, i.e., 5 A cm−2 @2.04 V with Nafion 115 membrane and 7 A cm−2 @ 2.07 V with Nafion 212 membrane, under a low catalyst loading of 0.72 mgIr cm−2. This study proves the importance and feasibility of agglomerate engineering in further elevating the performance of PEMWE.

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Iridium and IrOx nanoparticles: an overview and review of syntheses and applications

Cited by 42 publications

References 213 publications

Surfactant-free colloidal syntheses of precious metal nanoparticles for improved catalysts

Surfactant-free colloidal syntheses of precious metal nanoparticles for improved catalysts

Chemical insights on the formation of colloidal iridium nanoparticles from in situ X-ray total scattering: Influence of precursors and cati-ons on the reaction pathway

Agglomerate Engineering to Boost PEM Water Electrolyzer Performance

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