Jonathan Quinson

Aarhus University | AU · Department of Engineering

Surfactant-free syntheses of colloidal nanomaterials present several potential benefits for various applications, e.g. in catalysis or medicine. However, controlled colloidal syntheses of metal nanoparticles obtained by the reduction of a precursor in a low viscosity liquid phase without surfactants remain scarce. Here, the features of a room tempe...

Large progress has been made towards commercialization of polymer electrolyte membrane fuel cells (PEMFCs) through the development of highly active and robust Pt-Co alloy catalysts for oxygen reduction reaction (ORR).[1,2] However, most ORR catalyst materials suffer from the extremely corrosive conditions occurring during start-up/shut-down (SUSD)....

State-of-the-art industrial electrocatalysts for the oxygen evolution reaction (OER) under acidic conditions are Ir-based. Considering the scarce supply of Ir, it is imperative to use the precious metal as efficiently as possible. In this work, we immobilized ultrasmall Ir and Ir0.4Ru0.6 nanoparticles on two different supports to maximize their dis...

Gold nanoparticles are easily obtained by a range of room temperature processes. In particular, polyols-based syntheses performed in alkaline conditions without the need for surfactants lead to small size nanoparticles around 10 nm in diameter. While highly viscous polyols, such as glycerol, have been the most studied polyols with which to perform...

A room temperature surfactant-free synthesis of gold nanoparticles in the size range 10–20 nm that only requires HAuCl4 as the precursor, NaOH as the base, water as the solvent and a mono-alcohol such as methanol or ethanol as the reducing agent, has recently been detailed. This approach is promisingly simple to obtain colloids stable for months. H...

State-of-the-art industrial electrocatalysts for the oxygen evolution reaction (OER) under acidic conditions are Ir-based. Considering the scarce supply of Ir, it is imperative to use the precious metal as efficiently as possible. In this work, we immobilized ultrasmall Ir and Ir0.4Ru0.6 nanoparticles on two different supports to maximize their dis...

Gold nanoparticles (Au NPs) and gold-based nanomaterials combine unique properties relevant for medicine, imaging, optics, sensing, catalysis, and energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of Au NPs, there is a need for more sustainable and tractable synthetic strategies...

Gold nanoparticles (AuNPs) and gold-based nanomaterials combine unique properties relevant for medicine, biomedical applications, imaging, optics, sensing, catalysis or energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of AuNPs, there is a need for more sustainable and tractable...

Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles have also been a key for the development of kinetic models of nanomaterial formation. However, compared to other metals such as gold or platinum, knowledge on the nature of prenucleation species and structural insight...

Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles 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 pathway of iridiu...

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...

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 cont...

High-entropy alloy (HEA) electrocatalysts offer a vast composition space that awaits exploration to identify interesting materials for energy conversion reactions. While attempts have been made to explore the composition space of HEA thin-film libraries and compare experimental and computational studies, no corresponding approaches exist for HEA na...

Precious metal nanoparticles are key for a range of applications ranging from catalysis and sensing to medicine. While gold (Au), silver (Ag), platinum (Pt), palladium (Pd) or ruthenium (Ru) nanoparticles have been widely studied, other precious metals are less investigated. Osmium (Os) is one of the least studied of the precious metals. However, O...

The production of hydrogen via acidic electrochemical water splitting is an important pillar towards more sustainability. The overall water electrolysis is hindered by the slow kinetics of the oxygen evolution reaction (OER). Therefore, the catalyst material for the anode still requires optimization. Hereby, we present two highly active OER catalys...

Herein, we report a straightforward approach for the in situ preparation of Pt–Au alloy nanoparticles from Pt + xAu/C nanocomposites using monometallic colloidal nanoparticles as starting blocks. Four different compositions with fixed Pt content and varying Pt to Au mass ratios from 1:1 up to 1:7 were prepared as formic acid oxidation reaction (FAO...

Gold nanoparticles (AuNPs) and gold-based nanomaterials combine unique properties relevant for medicine, biomedical applications, imaging, optics, sensing, catalysis or energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of AuNPs, there is a need for more sustainable and tractable...

Based on H‐cell measurements, gold (Au) is one of the most selective catalysts for the CO 2 reduction reaction (CO 2 RR) to CO. To ensure a high dispersion, typically Au small nanoparticles (NPs) are used as catalyst. However, the preparation of small Au NPs based on conventional synthesis methods often requires the use of surfactants such as polyv...

Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts under high mass transport conditions, while maintaining the simplicity of rotating disk electrode (RDE) setups. In contrast to experimental RDE protocols, for investigations using GDE setups only few syste...

Intermetallic nanoparticles (NPs) have shown enhanced catalytic properties as compared to their disordered alloy counterparts. To advance their use in green energy, it is crucial to understand what controls the formation of intermetallic NPs over alloy structures. By carefully selecting the additives used in NP synthesis, it is here shown that mono...

Precious metal nanoparticles are key for a range of applications ranging from catalysis and sensing to medicine. While gold (Au), silver (Ag), platinum (Pt), palladium (Pd) or ruthenium (Ru) nanoparticles have been widely studied, other precious metals are less investigated. Osmium (Os) is one of the least studied of the precious metals. However, O...

Precious metals are key in various fields of research and precious metal nanomaterials are directly relevant for optics, catalysis, pollution management, sensing, medicine, and many other applications. Iridium based nanomaterials are less studied than metals like gold, silver or platinum. A specific feature of iridium nanomaterials is the relativel...

The successful study, understanding, optimization and ultimately scaling up of electroactive and stable electrodes strongly rely on the careful design and preparation of electrocatalytic materials. In particular, precious metal nanoparticles are key electrocatalysts for a wide range of reactions. Colloidal syntheses offer several advantages to deve...

A surfactant-free synthesis of precious metal nanoparticles (NPs) performed in alkaline low-boiling-point solvents has been recently reported. Monoalcohols are here investigated as solvents and reducing agents to obtain colloidal Os nanoparticles by using low-temperature (<100 °C) surfactant-free syntheses. The effect of the precursor (OsCl3 or H2O...

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane f...

The development of nanomaterials often relies on wet-chemical synthesis performed in reflux setups using round-bottom flasks. Here, an alternative approach to synthesize nanomaterials is presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent and energy, generates less waste, provides safer conditions,...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux-setups using round-bottom-flasks. An alternative approach to synthesize nanomaterials is here presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent, uses less energy, generates less waste, provides safer condi...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux-setups using round-bottom-flasks. An alternative approach to synthesize nanomaterials is here presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent, uses less energy, generates less waste, provides safer condi...

The lack of a robust and standardized experimental test bed to investigate the performance of catalyst materials for the electrochemical CO2 reduction reaction (ECO2RR) is one of the major challenges in this field of research. To best reproduce and mimic commercially relevant conditions for catalyst screening and testing, gas diffusion electrode (G...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) is here presented to provide insights into the changes in mean particle sizes and phase fractions in fuel cell catalyst layers during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal Pt/C catalyst was chosen that consists of two distinguishable particle...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) is here presented to provide insights into the changes in mean particle sizes and phase fractions in fuel cell catalyst layers during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal Pt/C catalyst was chosen that consists of two distinguishable particle...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) is here presented to provide insights into the changes in mean particle sizes and phase fractions in fuel cell catalyst layers during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal Pt/C catalyst was chosen that consists of two distinguishable particle...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) is here presented to provide insights into the changes in mean particle sizes and phase fractions in fuel cell catalyst layers during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal Pt/C catalyst was chosen that consists of two distinguishable particle...

Based on H-cell measurements, gold (Au) is one of the most selective catalysts for the CO2 reduction reaction (CO2RR) to CO. To ensure a high dispersion, typically Au small nanoparticles (NPs) are used as catalyst. However, the preparation of small Au NPs based on conventional synthesis methods often requires the use of surfactants such as polyviny...

Based on H-cell measurements, gold (Au) is one of the most selective catalysts for the CO2 reduction reaction (CO2RR) to CO. To ensure a high dispersion, typically Au small nanoparticles (NPs) are used as catalyst. However, the preparation of small Au NPs based on conventional synthesis methods often requires the use of surfactants such as polyviny...

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane f...

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane f...

A surfactant-free synthesis of precious metal nanoparticles performed in low boiling point solvents and in alkaline conditions has been reported recently. This strategy presents several advantages over alternative colloidal syntheses. The resulting nanoparticles are readily relevant for applications like catalysis and the synthetic process is compa...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux-setups using round-bottom-flasks. An alternative approach to synthesize nanomaterials is here presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent, uses less energy, generates less waste, provides safer condi...

A surfactant-free synthesis of precious metal nanoparticles performed in low boiling point solvents and in alkaline conditions has been reported recently. This strategy presents several advantages over alternative colloidal syntheses. The resulting nanoparticles are readily relevant for applications like catalysis and the synthetic process is compa...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux-setups using round-bottom-flasks. An alternative approach to synthesize nanomaterials is here presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent, uses less energy, generates less waste, provides safer condi...

The development of highly active catalysts relies on the development of simple synthesis methods. Ir based materials are state of the art catalysts for the oxygen evolution reaction (OER), the anode reaction for water electrolysis, a key technology for more sustainable energy supply. Here, metallic Ir NPs ca. 2 nm in diameter are simply obtained by...

Colloidal syntheses of nanoparticles (NPs) are one of the preferred approaches to prepare precious metal catalysts. Unfortunately, most colloidal syntheses developed require stabilizing agents to avoid NP agglomeration and/or control NP size and morphology. While these surfactants can bring positive features, they typically block catalytically acti...

A surfactant-free synthesis of precious metal nanoparticles performed in low boiling point solvents and in alkaline conditions has been reported recently. This strategy presents several advantages over alternative colloidal syntheses. The resulting nanoparticles are readily relevant for applications like catalysis and the synthetic process is compa...

A surfactant-free synthesis of precious metal nanoparticles performed in low boiling point solvents and in alkaline conditions has been reported recently. This strategy presents several advantages over alternative colloidal syntheses. The resulting nanoparticles are readily relevant for applications like catalysis and the synthetic process is compa...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux setups using round-bottom-flasks. An alternative approach to synthesise nanomaterials is presented that uses glass tubes designed for NMR analysis as reactors. It uses less solvent, generates less waste, provides safer conditions, is less prone to contaminat...

The development of nanomaterials often relies on wet-chemical syntheses performed in reflux setups using round-bottom-flasks. An alternative approach to synthesise nanomaterials is presented that uses glass tubes designed for NMR analysis as reactors. It uses less solvent, generates less waste, provides safer conditions, is less prone to contaminat...

Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts. As compared to the state-of-the-art in fundamental research, i.e., rotating disk electrode (RDE) measurements, GDE measurements offer several advantages. Most importantly mass transport limitations, inher...

Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts. As compared to the state-of-the-art in fundamental research, i.e., rotating disk electrode (RDE) measurements, GDE measurements offer several advantages. Most importantly mass transport limitations, inher...

In recent years, the development of complex multi-metallic nanomaterials like high entropy alloy (HEA) catalysts has gained popularity. Composed of 5 or more metals, the compositions of HEAs exhibit extreme diversity. This is both a promising avenue to identify new catalysts and a severe constraint on their preparation and study. To address the cha...

In recent years, the development of complex multi-metallic nanomaterials like high entropy alloy (HEA) catalysts has gained popularity. Composed of 5 or more metals, the compositions of HEAs exhibit extreme diversity. This is both a promising avenue to identify new catalysts and a severe constraint on their preparation and study. To address the cha...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) in grazing incidence configuration is presented as a new approach to provide depth-dependent insights into the changes in mean particle sizes and phase fractions occurring for fuel cell catalysts during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal P...

The combination of operando small- and wide-angle X-ray scattering (SAXS, WAXS) in grazing incidence configuration is presented as a new approach to provide depth-dependent insights into the changes in mean particle sizes and phase fractions occurring for fuel cell catalysts during accelerated stress tests (ASTs). As fuel cell catalyst, a bimodal P...

Much research effort has been devoted to the development of effective catalysts for the electrochemical reduction of CO2 (CO2RR). For CO2RR, the most common catalyst screening method is performed in a H-cell configuration where the reactant CO2 gas is usually dissolved in an aqueous bicarbonate-based electrolyte. However, the low solubility of CO2...

Much research effort has been devoted to the development of effective catalysts for the electrochemical reduction of CO2 (CO2RR). For CO2RR, the most common catalyst screening method is performed in a H-cell configuration where the reactant CO2 gas is usually dissolved in an aqueous bicarbonate-based electrolyte. However, the low solubility of CO2...

The polyol synthesis is a well-established method to form so-called “surfactant-free” nanoparticles (NPs). In the present study, the NP size resulting from the thermal reduction of the precursors H2PtCl6, H2Pt(OH)6, or Pt(acac)2 in presence of the bases NaOH or Na(acac) at different concentrations is studied. It is shown that the size control depen...

In recent years, the development of complex multi-metallic nanomaterials like high entropy alloy (HEA) catalysts has gained popularity. Composed of 5 or more metals, the compositions of HEAs exhibit extreme diversity. This is both a promising avenue to identify new catalysts and a severe constraint on their preparation and study. To address the cha...

In recent years, the development of complex multi-metallic nanomaterials like high entropy alloy (HEA) catalysts has gained popularity. Composed of 5 or more metals, the compositions of HEAs exhibit extreme diversity. This is both a promising avenue to identify new catalysts and a severe constraint on their preparation and study. To address the cha...

Much research effort has been devoted to the development of effective catalysts for the electrochemical reduction of CO2 (CO2RR). For CO2RR, the most common catalyst screening method is performed in a H-cell configuration where the reactant CO2 gas is usually dissolved in an aqueous bicarbonate-based electrolyte. However, the low solubility of CO2...

Much research effort has been devoted to the development of effective catalysts for the electrochemical reduction of CO2 (CO2RR). For CO2RR, the most common catalyst screening method is performed in a H-cell configuration where the reactant CO2 gas is usually dissolved in an aqueous bicarbonate-based electrolyte. However, the low solubility of CO2...

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane f...

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane f...

The polyol synthesis is a well-established method to form so-called “surfactant-free” NPs that can be tailored, e.g., in size. The standard procedure of reducing H2PtCl6 or H2PtBr6 in presence of NaOH has been intensively investigated as well as the influence of the counter cation of the base. However, the base anion influence has not been explored...

The polyol synthesis is a well-established method to form so-called “surfactant-free” NPs that can be tailored, e.g., in size. The standard procedure of reducing H2PtCl6 or H2PtBr6 in presence of NaOH has been intensively investigated as well as the influence of the counter cation of the base. However, the base anion influence has not been explored...