Determining the role of redox-active materials during laser-induced water decomposition

Kalus, Mark-Robert; Lanyumba, Riskyanti; Lorenzo-Parodi, Nerea; Jochmann, Maik A.; Kerpen, Klaus; Hagemann, Ulrich; Schmidt, Torsten; Barcikowski, Stephan; Gökce, Bilal

doi:10.1039/c9cp02663k

Cited by 50 publications

(90 citation statements)

References 86 publications

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“…A closer look to the spectra reveals slight differences after laser irradiation, as a higher absorption of the C–O peak at 1060 cm −1 and the C–H peaks at 2860 cm −1 and 1470 cm −1 . This fact indicates the increased presence of C–OH and CH 2 surface groups, which can be explained due to the higher surface area after particle size reduction and the generation of molecular O and H based radicals or molecules from water splitting during laser irradiation [ 58 ].…”

Section: Resultsmentioning

confidence: 99%

Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion

et al. 2020

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Driven by the rapid development of additive manufacturing technologies and the trend towards mass customization, the development of new feedstock materials has become a key aspect. Additivation of the feedstock with nanoparticles is a possible route for tailoring the feedstock material to the printing process and to modify the properties of the printed parts. This study demonstrates the colloidal additivation of PA12 powder with laser-synthesized carbon nanoparticles at >95% yield, focusing on the dispersion of the nanoparticles on the polymer microparticle surface at nanoparticle loadings below 0.05 vol%. In addition to the descriptors “wt%” and “vol%”, the descriptor “surf%” is discussed for characterizing the quantity and quality of nanoparticle loading based on scanning electron microscopy. The functionalized powders are further characterized by confocal dark field scattering, differential scanning calorimetry, powder rheology measurements (avalanche angle and Hausner ratio), and regarding their processability in laser powder bed fusion (PBF-LB). We find that heterogeneous nucleation is induced even at a nanoparticle loading of just 0.005 vol%. Finally, analysis of the effect of low nanoparticle loadings on the final parts’ microstructure by polarization microscopy shows a nanoparticle loading-dependent change of the dimensions of the lamellar microstructures within the printed part.

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Section: Resultsmentioning

confidence: 99%

Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion

et al. 2020

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“…For the ablation of the Pt 0.66 Pd 0.33 target, the same trend in the productivity of total mass as well as the catalytically relevant nanoparticle size fraction below 10 nm was found ( Figure S2 ). Interestingly, when comparing the maximal ablation rate for Pt and Pt 0.66 Pd 0.33 , the ablation rate correlates with the material density [ 61 ] so that a similar volume-related ablation rate of about 0.27 cm³/h was found for both (see Figure 2 and Figure S2 ).…”

Section: Resultsmentioning

confidence: 99%

Increasing the Size-Selectivity in Laser-Based g/h Liquid Flow Synthesis of Pt and PtPd Nanoparticles for CO and NO Oxidation in Industrial Automotive Exhaust Gas Treatment Benchmarking

et al. 2020

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PtPd catalysts are state-of-the-art for automotive diesel exhaust gas treatment. Although wet-chemical preparation of PtPd nanoparticles below 3 nm and kg-scale synthesis of supported PtPd/Al2O3 are already established, the partial segregation of the bimetallic nanoparticles remains an issue that adversely affects catalytic performance. As a promising alternative, laser-based catalyst preparation allows the continuous synthesis of surfactant-free, solid-solution alloy nanoparticles at the g/h-scale. However, the required productivity of the catalytically relevant size fraction <10 nm has yet to be met. In this work, by optimization of ablation and fragmentation conditions, the continuous flow synthesis of nanoparticles with a productivity of the catalytically relevant size fraction <10 nm of >1 g/h is presented via an in-process size tuning strategy. After the laser-based preparation of hectoliters of colloid and more than 2 kg of PtPd/Al2O3 wash coat, the laser-generated catalysts were benchmarked against an industry-relevant reference catalyst. The conversion of CO by laser-generated catalysts was found to be equivalent to the reference, while improved activity during NO oxidation was achieved. Finally, the present study validates that laser-generated catalysts meet the size and productivity requirements for industrial standard operating procedures. Hence, laser-based catalyst synthesis appears to be a promising alternative to chemical-based preparation of alloy nanoparticles for developing industrial catalysts, such as those needed in the treatment of exhaust gases.

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“…The redox chemistry between the target material and water affects not only the NP productivity during long‐term ablation but also the oxidation degree of the final NPs, as also theoretically predicted by Reichenberger et al. based on Nernst equation and correlated to experimental findings [35, 62, 63] However, all these experiments were performed for multi‐pulse laser ablation with repetition rates in the kHz regime. Hence, cavitation bubbles, [16, 17] persistent bubbles [60–63] or NPs [61–63, 68–70] formed during LAL induce cross‐effects.…”

Section: Introductionmentioning

confidence: 85%

“…However, the time regime of the rebound/collapse of the bubble must also be considered but is often neglected as most studies focus on the primary cavitation bubble cycle. Within this context, several studies have demonstrated that water is decomposed during LAL resulting in the formation of molecular hydrogen, oxygen, and hydrogen peroxide [60–67] . The individual formation rates of these decomposition products depend strongly on the type of the ablated material.…”

Section: Introductionmentioning

confidence: 99%

How the Physicochemical Properties of the Bulk Material Affect the Ablation Crater Profile, Mass Balance, and Bubble Dynamics During Single‐Pulse, Nanosecond Laser Ablation in Water

Kalus

Barcikowski

Gökce

2021

Chemistry A European J

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Understanding the key steps that drive the laser‐based synthesis of colloids is a prerequisite for learning how to optimize the ablation process in terms of nanoparticle output and functional design of the nanomaterials. Even though many studies focus on cavitation bubble formation using single‐pulse ablation conditions, the ablation efficiency and nanoparticle properties are typically investigated under prolonged ablation conditions with repetition rate lasers. Linking single‐pulse and multiple‐pulse ablation is difficult due to limitations induced by gas formation cross‐effects, which occur on longer timescales and depend on the target materials’ oxidation‐sensitivity. Therefore, this study investigates the ablation and cavitation bubble dynamics under nanosecond, single laser pulse conditions for six different bulk materials (Au, Ag, Cu, Fe, Ti, and Al). Also, the effective threshold fluences, ablation volumes, and penetration depths are quantified for these materials. The thermal and chemical properties of the corresponding bulk materials not only favor the formation of larger spot sizes but also lead to the highest molar ablation efficiencies for low melting materials such as aluminum. Furthermore, the concept of the cavitation bubble growth linked with the oxidation sensitivity of the ablated material is discussed. With this, evidence is provided that intensive chemical reactions occurring during the very early timescale of ablation are significantly enhanced by the bubble collapse.

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Determining the role of redox-active materials during laser-induced water decomposition

Abstract: The decomposition of water and the formation of molecular hydrogen, oxygen, and hydrogen peroxide during laser ablation of redox-active materials is systematically studied and related to the ablation rate and oxidation degree of the nanoparticles.

Cited by 50 publications

References 86 publications

Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion

Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion

Increasing the Size-Selectivity in Laser-Based g/h Liquid Flow Synthesis of Pt and PtPd Nanoparticles for CO and NO Oxidation in Industrial Automotive Exhaust Gas Treatment Benchmarking

How the Physicochemical Properties of the Bulk Material Affect the Ablation Crater Profile, Mass Balance, and Bubble Dynamics During Single‐Pulse, Nanosecond Laser Ablation in Water

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