Laura Keskiväli

Dr. Laura Keskiväli


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 January 2020 in Chemical Communications
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Journal Article
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PAPäivi Tellervo Aakko-Saksa
Päivi Tellervo Aakko-Saksa
MVM. Vehkamäki
M. Vehkamäki
Marianna L KemellMarianna L Kemell
Marianna L Kemell
LKLaura Keskiväli
Laura Keskiväli
Pekka SimellPekka Simell
Pekka Simell
TRT. Repo
T. Repo
A liquid organic hydrogen carrier (LOHC) is an interesting concept for hydrogen storage. Pt supported on a rutile-anatase form of titania was found to be an active catalyst system for dehydrogenation of perhydrogenated dibenzyl toluene.

2 July 2018 in ACS Omega
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Journal Article
Open access
LKLaura Keskiväli
Laura Keskiväli
MPMatti Putkonen
Matti Putkonen
EPEini Puhakka
Eini Puhakka
EKEija Kenttä
Eija Kenttä
JKJeroen Kint
Jeroen Kint
Pekka SimellPekka Simell
Pekka Simell
Novel coating materials are constantly needed for current and future applications in the area of microelectronics, biocompatible materials, and energy-related devices. Molecular layer deposition (MLD) is answering this cry and is an increasingly important coating method for organic and hybrid organic–inorganic thin films. In this study, we have focused on hybrid inorganic–organic coatings, based on trimethylaluminum, monofunctional aromatic precursors, and ring-opening reactions with ozone. We present the MLD processes, where the films are produced with trimethylaluminum, one of the three aromatic precursors (phenol, 3-(trifluoromethyl)phenol, and 2-fluoro-4-(trifluoromethyl)benzaldehyde), ozone, and the fourth precursor, hydrogen peroxide. According to the in situ Fourier-transform infrared spectroscopy measurements, the hydrogen peroxide reacts with the surface carboxylic acid group, forming a peroxyacid structure (C(O)–O–OH), in the case of all three processes. In addition, molecular modeling for the processes with three different aromatic precursors was carried out. When combining these modeling results with the experimental research data, new interesting aspects of the film growth, reactions, and properties are exploited.

11 August 2022 in Physical Chemistry Chemical Physics
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NHNiko Heikkinen
Niko Heikkinen
JLJuha Lehtonen
Juha Lehtonen
LKLaura Keskiväli
Laura Keskiväli
JYJihong Yim
Jihong Yim
SSShwetha Shetty
Shwetha Shetty
MPMatti Putkonen
Matti Putkonen
Atomic layer deposition (ALD) was used to deposit a protective overcoating (Al2O3) on an industrially relevant Co-based Fischer–Tropsch catalyst.

26 August 2021 in Coatings
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LKLaura Keskiväli
Laura Keskiväli
PHPirjo Heikkilä
Pirjo Heikkilä
EKEija Kenttä
Eija Kenttä
TVTommi Virtanen
Tommi Virtanen
HRHille Rautkoski
Hille Rautkoski
MPMatti Putkonen
Matti Putkonen
The growth mechanism of Atomic Layer Deposition (ALD) on polymeric surfaces differs from growth on inorganic solid substrates, such as silicon wafer or glass. In this paper, we report the growth experiments of Al2O3 and ZnO on nonwoven poly-L-lactic acid (PLLA), polyethersulphone (PES) and cellulose acetate (CA) fibres. Material growth in both ALD and infiltration mode was studied. The structures were examined with a scanning electron microscope (SEM), scanning transmission electron microscope (STEM), attenuated total reflectance-fourier-transform infrared spectroscopy (ATR-FTIR) and 27Al nuclear magnetic resonance (NMR). Furthermore, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis were used to explore the effect of ALD deposition on the thermal properties of the CA polymer. According to the SEM, STEM and ATR-FTIR analysis, the growth of Al2O3 was more uniform than ZnO on each of the polymers studied. In addition, according to ATR-FTIR spectroscopy, the infiltration resulted in interactions between the polymers and the ALD precursors. Thermal analysis (TGA/DSC) revealed a slower depolymerization process and better thermal resistance upon heating both in ALD-coated and infiltrated fibres, more pronounced on the latter type of structures, as seen from smaller endothermic peaks on TA.

24 May 2021 in Catalysts
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NHNiko Heikkinen
Niko Heikkinen
LKLaura Keskiväli
Laura Keskiväli
PEPatrik Eskelinen
Patrik Eskelinen
Matti ReinikainenMatti Reinikainen
Matti Reinikainen
MPMatti Putkonen
Matti Putkonen
Atomic layer deposition (ALD) was used to prepare a thin alumina layer on Fischer–Tropsch catalysts. Co-Pt-Si/γ-Al2O3 catalyst was overcoated with 15–40 cycles of Al2O3 deposited from trimethylaluminum (TMA) and water vapor, followed by thermal annealing. The resulting tailored Fischer–Tropsch catalyst with 35 cycle ALD overcoating had increased activity compared to unmodified catalyst. The increase in activity was achieved without significant loss of selectivity towards heavier hydrocarbons. Altered catalyst properties were assumed to result from cobalt particle stabilization by ALD alumina overcoating and nanoscale porosity of the overcoating. In addition to optimal thickness of the overcoat, thermal annealing was an essential part of preparing ALD overcoated catalyst.

23 February 2022 in ACS Omega
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Journal Article
Open access
NHNiko Heikkinen
Niko Heikkinen
LKLaura Keskiväli
Laura Keskiväli
JPJasmiina Palo
Jasmiina Palo
Matti ReinikainenMatti Reinikainen
Matti Reinikainen
MPMatti Putkonen
Matti Putkonen
Atomic layer deposition (ALD) and molecular layer deposition (MLD) methods were used to prepare overcoatings on a cobalt-based Fischer–Tropsch catalyst. A Co–Pt–Si/γ-Al2O3 catalyst (21.4 wt % Co, 0.2 wt % Pt, and 1.6 wt % Si) prepared by incipient wetness impregnation was ALD overcoated with 30–40 cycles of trimethylaluminum (TMA) and water, followed by temperature treatment (420 °C) in an inert nitrogen atmosphere. MLD-overcoated samples with corresponding film thicknesses were prepared by using TMA and ethylene glycol, followed by temperature treatment (400 °C) in an oxidative synthetic air atmosphere. The ALD catalyst (40 deposition cycles) had a positive activity effect upon moderate water addition (PH2O/PH2 = 0.42), and compared with a non-overcoated catalyst, it showed resistance to irreversible deactivation after co-fed water conditions. In addition, MLD overcoatings had a positive effect on the catalyst activity upon moderate water addition. However, compared with a non-overcoated catalyst, only the 10-cycle MLD-overcoated catalyst retained increased activity throughout high added water conditions (PH2O/PH2 = 0.71). All catalyst variations exhibited irreversible deactivation under high added water conditions.