Impact of Single-Pulse, Low-Intensity Laser Post-Processing on Structure and Activity of Mesostructured Cobalt Oxide for the Oxygen Evolution Reaction

Budiyanto, Eko; Zerebecki, Swen; Weidenthaler, Claudia; Kox, Tim; Kenmoe, Stéphane; Spohr, Eckhard; DeBeer, Serena; Rüdiger, Olaf; Reichenberger, Sven; Barcikowski, Stephan; Tüysüz, Harun

doi:10.1021/acsami.1c08034

Cited by 34 publications

(63 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The IR drop was compensated at 85% for all measurements. Pulse-by-Pulse laser doping of the colloidal Co3O4 sample with Fe 3+ cations was conducted in several subsequent passages of the colloidal Co3O4 dispersion through a self-developed flat liquid jet setup (previously introduced 28 , successfully employed 27,29 , and depicted in Fig. 1).…”

Section: Materials Characterizationmentioning

confidence: 99%

“…Hereby, PLPP holds particular opportunities since PLPP has been reported to kinetically stabilize catalysis-relevant metastable structures such as amorphous, 24,25 defective 19 , and/or single-atom catalysts 26 while maintaining the particle size and oxide phase when choosing a sufficient laser intensity regime. 27,28 In this study, we investigated a heat-induced, diffusion-controlled pulse-by-pulse laser-doping strategy of spinel-based Co3O4 catalyst particles with iron cations to systematically correlate the laser-imprinted dopant surface-concentration with the catalytic activity (or selectivity). Laserdoping of the colloidal nanoparticles was conducted using a previously developed continuously operating flat liquid jet setup.…”

Section: Introductionmentioning

confidence: 99%

“…28 The continuous flow ensures the illumination of each colloid volume element by a single laser pulse during one passage through the setup. 28 Multiple passages allow for a gradual pulse-by-pulse processing 27,29 and hence a laser pulse-resolved doping of the colloid as well as the correlation of the doping process and the catalytic activity. The flat liquid jet geometry of the setup ensures uniform illumination conditions (laser fluence) which were found mandatory to maintain the initial particle properties such as size, crystal phase, and BET-area (at adequately low laser intensity).…”

Section: Introductionmentioning

confidence: 99%

“…The flat liquid jet geometry of the setup ensures uniform illumination conditions (laser fluence) which were found mandatory to maintain the initial particle properties such as size, crystal phase, and BET-area (at adequately low laser intensity). 27,29 On solving 2 nd Fick's equation considering relevant temperatures and heating times of pulsed laser heating it will be shown that the developed laserinduced surface doping method for nanoparticles, allows the control of the doping depth by the variation of the number of applied pulses. XRD measurements reveal an increase of the Co3O4 lattice parameter with the rising number of step-by-step applied laser pulses indicating the incorporation of Fe into the Co3O4 lattice.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Gradually Fe-doped Co3O4 nanoparticles in 2-propanol and water oxidation catalysis with single laser pulse resolution.

Zerebecki

Schott

Salamon

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Controlling the surface composition of colloidal nanoparticles is still a challenging yet mandatory prerequisite in catalytic studies to investigate composition-activity trends, active sites, and reaction mechanisms without superposition of particle size- or morphology-effects. Laser post-processing of colloidal nanoparticles has been employed previously to create defects in oxide nanoparticles, while the possibility of laser-based cation doping of colloidal nanoparticles without affecting their size, remains mostly unaccounted for. Consequently, at the example of doping iron into colloidal Co3O4 spinel nanoparticles, we developed a pulse-by-pulse laser cation doping method to provide catalyst series with gradual surface composition but maintained extrinsic properties such as phase, size, and surface area for catalytic studies. Laser pulse number-resolved doping series were prepared at laser intensity chosen to selectively heat the Co3O4-NPs to roughly 1000 K and enable cation diffusion of surface-adsorbed Fe3+ into the Co3O4 lattice while maintaining the spinel phase, particle size, and surface area. The combination of bulk-sensitive X-ray fluorescence (XRF) and surface-sensitive X-ray photoelectron spectroscopy (XPS) was used to confirm a surface enrichment of the Fe-dopant. XRD, Magnetometry, and Mössbauer spectroscopy revealed an increasing interaction between Fe and the antiferromagnetic Co3O4 with an increasing number of pulses, in line with a proposed laser-induced surface doping of colloidal Co3O4 with Fe. Using Fick’s second law the thermal diffusion-related doping depth was estimated to be roughly 2 nm after 4 laser pulses. At the example of gas-phase 2-propanol oxidation and liquid-phase oxygen evolution reaction, the activity of the laser-doped catalysts is in good agreement with previous observations on binary iron-cobalt oxides. The catalytic activity was found to linearly increases with the calculated doping depth in both reactions, while only catalysts processed with at least one laser pulse were catalytically stable, highlighting the presented method in providing comparable, active, and stable gradual catalyst doping series for future catalytic studies.

show abstract

Section: Materials Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gradually Fe-doped Co3O4 nanoparticles in 2-propanol and water oxidation catalysis with single laser pulse resolution.

Zerebecki

Schott

Salamon

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Not solely Co-containing transition metal oxides are interesting for catalytic oxidation reactions, also mixed Co and Fe transition metal oxides are used either within perovskites or spinel structures [22][23][24][25][26][27][28][29][30][31][32]. With increasing Fe content in spinels, the reducibility decreased steadily until inversion of the spinel materials was found experimentally.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Reactive Oxygen Species on Cobalt-Containing Spinel Oxides in Cyclic CO Oxidation

et al. 2021

Self Cite

View full text Add to dashboard Cite

Reactive oxygen species (ROS) are considered to be responsible for the high catalytic activity of transition metal oxides like Co3-xFexO4 in oxidation reactions, but the detailed influences of catalyst composition and morphology on the formation of these reactive oxygen species are not fully understood. In the presented study, Co3O4 spinels of different mesostructures, i.e., particle size, crystallinity, and specific surface area, are characterized by powder X-ray diffraction, scanning electron microscopy, and physisorption. The materials were tested in CO oxidation performed in consecutive runs and compared to a Co3-xFexO4 composition series with a similar mesostructure to study the effects of catalyst morphology and composition on ROS formation. In the first run, the CO conversion was observed to be dominated by the exposed surface area for the pure Co-spinels, while a negative effect of Fe content in the spinels was seen. In the following oxidation run, a U-shaped conversion curve was observed for materials with high surface area, which indicated the in situ formation of ROS on those materials that were responsible for the new activity at low temperature. This activation was not stable at the higher reaction temperature but was confirmed after temperature-programmed oxidation (TPO). However, no activation after the first run was observed for low-surface-area and highly crystalline materials, and the lowest surface-area material was not even activated after TPO. Among the catalyst series studied here, a correlation of small particle size and large surface area with the ability for ROS formation is presented, and the benefit of a nanoscaled catalyst is discussed. Despite the generally negative effect of Fe, the highest relative activation was observed at intermediate Fe contents suggesting that Fe may be involved in ROS formation.

show abstract

Fluoride Substitution: Quantifying Surface Hydroxyls of Metal Oxides with Fluoride Ions

Lau,

Zerebecki,

Pielsticker

et al. 2024

Adv Materials Inter

View full text Add to dashboard Cite

Surface hydroxyls (OH) are crucial for heterogeneous catalysis in water. However, they are commonly characterized at solid–gas interfaces (e.g., FTIR, XPS, TGA), which may not represent the surface in aqueous environments. Here, the surface OH of five catalytically relevant oxides (Al2O3, ZrO2, TiO2, Fe2O3, Co3O4) are quantified by substituting them with F− ions at pH 3–10, where the surface fluoride (F) density is evaluated by XPS using the geometry factor for spherical particles. These results show that the surface F density peaks at around pH 4 across all oxides, but decreases at more basic pH due to increased OH− competition. Generally, oxides more abundant in surface OH can also accommodate more surface F, establishing F− ions as effective probes. While terminal F are likely the preferential substitution product, bridging F also appear to form at lower pH levels. Furthermore, fluoride substitution is applied to a series of Co3O4 gradually enriched with defects using pulsed laser defect engineering in liquid (PUDEL). This approach reveals a linear correlation between laser processing and surface OH density, which aligns with a previously observed improvement in OER activity, and is supported by additional DFT calculations here. This work will stimulate further studies adopting fluoride substitution to better understand the relationship between surface chemistry and catalytic processes in aqueous environments.

show abstract

Impact of Single-Pulse, Low-Intensity Laser Post-Processing on Structure and Activity of Mesostructured Cobalt Oxide for the Oxygen Evolution Reaction

Cited by 34 publications

References 69 publications

Gradually Fe-doped Co3O4 nanoparticles in 2-propanol and water oxidation catalysis with single laser pulse resolution.

Gradually Fe-doped Co3O4 nanoparticles in 2-propanol and water oxidation catalysis with single laser pulse resolution.

Dynamics of Reactive Oxygen Species on Cobalt-Containing Spinel Oxides in Cyclic CO Oxidation

Fluoride Substitution: Quantifying Surface Hydroxyls of Metal Oxides with Fluoride Ions

Contact Info

Product

Resources

About