Tuning Nano-Nickel Catalyst Hydrogenation Aptitude by On-the-Fly Zirconium Doping

Article abstract of DOI:10.1002/cctc.202000235

The effect of nano-Ni catalyst post-synthetic Zr-modification on hydrogenation reaction of 6-methyl-5-hepten-2-one was investigated in a fixed bed continuous-flow micro-reactor to produce fine chemicals. The catalytic performance revealed that Zr-doping achieved by surface organometallic chemistry approach modifies the natural aptitude of nickel to hydrogenate C=C bond, since the addition of small quantities of zirconium significantly increased the amount of unsaturated and saturated alcohols formed in 6-methyl-5-hepten-2-one hydrogenation. Quantum chemical calculations revealed a stronger interaction between Zr←O=C that promotes the formation of C=C semihydrogenation product and enhances the probability of complete hydrogenation. The on-the-fly strategy presented herein enables for rapid optimization and understanding of catalytic processes.

Full text of DOI:10.1002/cctc.202000235

The European Society Journal for Catalysis
Supported by
Accepted Article
Title: Tuning nano-nickel catalyst hydrogenation aptitude by on-the-fly
zirconium doping
Authors: Małgorzata Zienkiewicz-Machnik, Ilona Goszewska, Damian
Giziński, Anna Śrębowata, Katarzyna Kuzmowicz, Adam
Kubas, Krzysztof Matus, Dmytro Lisovytskiy, Marcin Pisarek,
and Jacinto Sa
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ChemCatChem
10.1002/cctc.202000235
FULL PAPER
Tuning nano-nickel catalyst hydrogenation aptitude by on-the-fly
zirconium doping
Małgorzata Zienkiewicz-Machnik*,[a] Ilona Goszewska,[a] Damian Giziński,[a] Anna Śrębowata,[a]
[
a]
[a]
[b]
[a]
[a]
Katarzyna Kuzmowicz, Adam Kubas, Krzysztof Matus, Dmytro Lisovytskiy, Marcin Pisarek, and
Jacinto Sá*[a, c]
Abstract: The effect of nano-Ni catalyst post-synthetic Zr-
modification on hydrogenation reaction of 6-methyl-5-hepten-2-one
was investigated in a fixed bed continuous-flow micro-reactor to
produce fine chemicals. The catalytic performance revealed that Zr-
doping achieved by surface organometallic chemistry approach
modifies the natural aptitude of nickel to hydrogenate C=C bond, since
the addition of small quantities of zirconium significantly increased the
amount of unsaturated and saturated alcohols formed in 6-methyl-5-
hepten-2-one hydrogenation. Quantum chemical calculations
revealed a stronger interaction between Zr←O=C that promotes the
formation of C=C semihydrogenation product and enhances the
probability of complete hydrogenation. The on-the-fly strategy
presented herein enables for rapid optimization and understanding of
catalytic processes.
so far focused on hydrogenation reactions catalysed by nano-Ni
[8-10]
catalysts supported on inert polymeric resins
alteration via on-the-fly surface modification [
and their
to increase the
9,10]
understanding of the processes and improve catalytic
[
9]
performance. We reported on the impact of particle accretion
and Sn-doping
[
10]
on the activity and selectivity in the
hydrogenation of α, β – unsaturated aldehydes and ketones. The
obtained results showed that on-the-fly modification offers a
simple workflow, cost-effective and adaptable strategy for
process intensification and optimization. Catalyst surface
alterations were achieved via surface organometallic chemistry
(SOMC) route. [11,12]
Sn-doping of parent Ni catalyst decreased the stability of the
adsorption complex and a switch of the thermodynamic order of
the favoured products. [10] Spurred by these findings, we decided
to extend our studies on the hydrogenation of 6-methyl-5-hepten-
[
10]
2-one to nano-Ni surface modification with zirconium.
Introduction
Zirconium was selected as dopant due to its difference in the
electronic structure including electronegativity compared to Ni
and Sn, which allows exploring both, the geometric and electronic
effects on hydrogenation of 6-methyl-5-hepten-2-one to produce
fine chemicals. [13,14] Ultimately, the study aims to establish if the
surface modifications and their impact in the catalysis can be
assigned to tabulated parameters (e.g., electronegativity, atom
radius, etc) or each element must be treated independently.
In the past few decades, organic processes conducted under flow
conditions have attracted growing attention due to significant
benefits in respect to environmental compatibility, safety and
efficiency. [1-4] In particular, chemoselective flow heterogeneous
catalysis yields desired products without significant levels of by-
product, avoiding costly, unsustainable and time-consuming
purification processes. This feature enables flow processes to be
assembled as a continuous multi-step workflow for the synthesis
[5-7]
of fine chemicals.
Results and Discussion
To fully capitulate the advantages offered by chemoselective flow
heterogeneous catalysis, novel catalysts must be developed that
can operate under the constrains of flow processes (e.g. minimum
particle size, stable to mechanical stress, etc). Additionally, the
new catalysts should be when possible made of transition metals,
which are abundant and cheap. Our research efforts have been
2
Nano-Ni parent catalyst (NiTSNH ) was obtained at room
temperature conditions, during one-pot, two-step synthesis where
Ni NPs were grafted on the polymeric resin terminated with amino
groups (TentaGel-S-NH
NiTSNH
2
, TSNH
2
). [8-10] The metal content in
was found to be 0.68% wt. [
8-10]
For the modification of
2
the parent catalyst with Zr we applied the procedure adopted to
synthesize the Ni-Sn catalyst. [10] Shortly, Ni-Zr material was
synthesised using ThalesNano H-Cube Pro™ flow micro-reactor
via surface organometallic chemistry route. The bimetallic catalyst
was subsequently flushed with ethanol to remove Zr ions excess
and used in 6-methyl-5-hepten-2-one hydrogenation immediately
after the preparation. The metals loading estimated for
NiZr0.12TSNH by atomic absorption spectroscopy was found to
2
be 0.74 wt%, where the subscript value corresponds to Ni/Zr
atomic ratio.
PXRD diffraction pattern of the bimetallic catalyst was recorded
and compared with the results reported previously [10] for the
polymeric resin and the monometallic Ni catalyst. Obtained
results show that the patterns are nearly the same (Fig. 1), with
two diffraction peaks associated with the polymer structure. The
lack of clear diffraction peak for metal nanoparticles is related to
[
a]
Dr M. Zienkiewicz-Machnik, I. Goszewska, Dr D. Giziński, Dr A.
Śrębowata, K. Kuzmowicz, Dr A. Kubas, Dr D. Lisovytskiy, Dr M.
Pisarek, Prof. J. Sá
Institute of Physical Chemistry, Polish Academy of Sciences
Kasprzaka 44/52, 01-224 Warsaw (Poland)
E-mail: mzienkiewiczmachnik@ichf.edu.pl, jacinto.sa@kemi.uu.se
K. Matus
Institute of Engineering Materials and Biomaterials
Silesian University of Technology
Konarskiego 18 A, 44-100 Gliwice (Poland)
Prof. J. Sá
[
[
b]
c]
Department of Chemistry, Ångström Laboratory
Uppsala University
Box 532, 751 20 Uppsala (Sweden)
Supporting information for this article is given via a link at the end of
the document.
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ChemCatChem
10.1002/cctc.202000235
FULL PAPER
the low metal loading but also to the small particles average size
(
size of the Zr speckles is not associated with Zr size but to EDS
pixel size and metal intensity.
estimated previously to be ca. 6.8 nm [10]). The polymeric
diffraction peaks did not change with metal anchoring, as well as
with the doping, which suggests that neither affects significantly
the support structure. [6,10]
XPS analysis was carried out to determine the oxidation state of
Ni in the un- and -doped catalysts. Ni 2p3/2 XPS spectra of the
catalysts (Fig. 3) are dominated by three signals ascribed to Ni0
(
maximum between 852 - 853 eV), [ Ni3+ (maximum between
15]
16]
8
8
8
55 - 856 eV) [ and Ni shake-up satellite (maximum between
60 - 861 eV). [ We have in the past the signal between 855 -
15]
[10]
based on the binding energy [17]
56 eV associated to Ni(OH)
2
but recent X-ray absorption spectroscopy (XAS) experiments
2
+
revealed that the signal could not be fitted to a Ni but rather to
3
+
[9]
3+
Ni . Our earlier studies also suggest that Ni form is located
primarily on the surface and is the product of surface passivation
with atmospheric air, [ which can be reduced partially or even
9]
0
fully to Ni during the catalytic test. There was a good match of
2 3
the XAS spectrum with Ni O we suspect that its structure is
different because Ni
somehow modulated/strained by the underlying Ni structure.
However, at present, we are unable to state what is the true
2
O
3
is not reducible at low temperature and
0
3
+
structure and coordination status of the Ni species. The ratio of
0
3+
Figure 1. PXRD patterns for the polymeric resin, mono- and bimetallic catalysts.
Ni :Ni was found to be roughly 1:3 for both samples. Zr 3d5/2 XPS
region for the bimetallic Ni-Zr catalyst was fitted with a single
4+
component with a maximum at 182.4 eV associated with Zr as
18,19]
ZrO
2
. [
The good match between the measured binding
reference prevents us
energy for Zr in the catalyst and the ZrO
2
from detecting any electron donation from Zr to Ni, meaning XPS
analysis suggests minimal to no electron donation.
Figure 3. Ni 2p3/2 XPS region of NiTSNH
the NiZr0.12TSNH signal.
2 2
and NiZr0.12TSNH . Insert fitting of
2
2
Figure 2. STEM images with EDS elemental mapping for NiZr0.12TSNH .
2
Since the NiTSNH used in this study is the same as the one
reported elsewhere, [10] the TEM images are not reported but the
Ni average particles size was estimated to be 6.8 nm. Zr-doping
did not affect the Ni average particles size in a measurable way.
To establish the presence of Zr on the surface of Ni, STEM
analysis with EDS-elemental mapping was investigated for the
doped catalyst (Fig. 2). We selected a large particle assemble
region to assess that Zr is only found when Ni is presence. Fig. 2
shows clearly that Zr is evenly distributed on the nickel surface
and absent when Ni is not present. Please take notice that the
Scheme 1. The possible pathways for 6-methyl-5-hepten-2-one hydrogenation.
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ChemCatChem
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Scheme 1 shows the reaction pathways for 6-methyl-5-hepten-2-
one hydrogenation. Continuous-flow hydrogenations of 6-methyl-
The decrease in the catalytic activity of Sn-doped catalyst was
connected with geometric blocking of the nickel surface. [10] On
the basis of STEM with EDS and XPS analysis and the fact that
Zr is inactive in the catalysis, the observed decrease in activity is
rationalized as geometric blocking of the nickel surface,
analogous to tin investigation.
5-hepten-2-one were carried out under different conditions of
temperature (25 – 100 C) and pressure (10 – 60 bar) using H-
Cube Pro™ micro-reactor. The catalytic experiment was
conducted with a constant reactant flow rate (0.5 ml/min).
6
-methyl-5-hepten-2-one hydrogenation over parent NiTSNH
2
Moreover, Zr doping modifies significantly the natural aptitude of
nickel to hydrogenate C=C bond (Fig. 5). The addition of small
amounts of zirconium results in the formation of other
hydrogenation products, namely unsaturated alcohol and
complete hydrogenation of 6-methyl-5-hepten-2-one. The
formation of unsaturated and/or saturated alcohol is strongly
dependent on the reaction conditions (Fig. 5). In most cases, both
saturated ketone and saturated alcohol are formed in the
catalysed reaction. Furthermore, the higher temperature (≥ 65 C)
causes the presence of all three hydrogenation products in the
post-reaction solution whereas at lower temperature there is no
unsaturated alcohol formation. Obtained data revealed that
independently of Zr content, the formation of complete
hydrogenation product is more favourable than the saturation of
C=O bond. This finding can be assigned to the high adsorption
strength of C=C hydrogenation product which leads to further
saturation of the carbonyl group and the formation of complete
hydrogenation product. It should be mentioned that the catalyst
maintained the reported performance for 5h on stream. Moreover,
EDXRF analysis of the post-reaction solutions had no measurable
amount of metals what suggests the effect of active phase
leaching is believed to be negligible. This was also confirmed by
XPS analysis of the spent catalyst (Fig. 6 and S1), which shows
no significant change in the metals content. Furthermore, XPS
revealed that the electronic structures of Ni and Zr were preserved,
confirming catalyst robustness.
yielded 100% selectivity toward saturated ketone formation and a
substrate activity of ca. 21 mol/min for a reaction conducted at
100 C and 40 bar of H
2
(the optimum values of temperature and
The addition of small quantities of zirconium to the
[
10]
pressure).
parent catalyst affected both activity and product selectivity.
Starting with activity studies (Fig. 4), the addition of Zr led to at
least twofold drop in activity no matter what temperature or H
pressure used, similar to what was found with Sn modification. [10]
The general trend is that activity increases when reaction
temperature and/or H
noticeable for the experiments ran at 45 C, where the catalytic
activity is only detected when H pressure reaches 60 bar.
2
2
pressure increases. This is particularly
2
Figure 4. Dependence of the reaction conditions on 6-methyl-5-hepten-2-one
catalytic activity over NiZr0.12TSNH with 0.5 ml/min flow rate of the reactant.
2
2
Figure 6. Ni 2p3/2 XPS region of NiZr0.12TSNH fresh and spent (after catalysis).
To comprehend further the structure-activity relationship, we
evaluated the effect of substrate flow rate on the catalytic
performance of Zr-doped material by carrying experiments with
Figure 5. Effect of the reaction conditions on the selectivity of 6-methyl-5-
0.3 and 1 ml/min substrate flow rates (Fig. 7 and S2-S5). Based
hepten-2-one hydrogenation over NiZr0.12TSNH
reactant.
2
with 0.5 ml/min flow rate of the
on the obtained results for different substrate flow rates, it can be
noticed that the catalytic activity increases in the following order:
0.3 ml/min < 0.5 ml/min << 1 ml/min. The observed trend was not
anticipated and suggests reversible substrate poisoning. At low
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ChemCatChem
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flow rates, the substrate is allowed to be on the surface for a
computations on larger nickel clusters doped with light atoms. [20]
Multiplicity of 7 was identified as the most stable spin state of the
nanoparticle model Ni13. Structures, where the zirconium replaced
central atom or was kind of ad-atom (similarly to Sn), were found
to be higher in energy by 11.3 or 32.3 kcal/mol, respectively. Zr
atom incorporation influences Ni...Ni average interatomic
distance that increases from 2.28 Å (Ni13) to 2.30 Å (Ni13Zr).
Closest Ni...Zr contact is 2.47 Å. According to Löwdin population
analysis, [21] Zr gains small positive charge of 0.13 a.u. while an
average charge of nickel atoms is -0.01 a.u. Furthermore, four
unpaired electrons of isolated Zr atom were found to be coupled
antiferromagnetically with the nickel atoms (Zr spin population of
longer period, leading to site saturation that blocks sites for H
2
activation. Contrastingly, at high flow rates, the sites cannot be
fully saturated thus providing sufficient amounts of activated
hydrogen to perform the hydrogenation reactions. The overall
selectivity was not affected significantly, which is expected since
the flows should not change meaningfully the catalytic aptitudes
to specific bond hydrogenation, considering that the catalyst is
stable throughout the reaction.
-
0.35, average Ni spin population of 0.49). The magnitude of
2
coupling is large as the calculated expectation value of S
operator (12.21) does not deviate much from the expected value
for six unpaired electrons (12.00).
According to Fig. 9, the interaction mode of the substrate with the
catalyst species is similar for both undoped and doped catalysts,
i.e. the interaction occurs via both C=O and C=C bonds. Small
positive charge associated with Zr atom makes it better Lewis acid
centre than Ni and carbonyl oxygen prefer interaction with
zirconium atom over nickel atom (see inset in Figure 9). The
binding energy of the substrate increases by 10.0 kcal/mol when
going from Ni13 to Ni13Zr catalyst. The degree of substrate
activation can be tracked back to changes in C=C and C=O bond
lengths that are 1.36 and 1.22 Å for isolated substrate,
respectively. The carbon-carbon double bond is elongated by
0.05 Å for Ni13 and 0.07 Å in the case of Ni13Zr. Carbonyl group is
altered in a more pronounced way with the elongation of 0.12 Å
and 0.17 Å for the two catalysts, respectively.
Figure 7. The reactant flow rate impact on catalytic performance of
NiZr0.12TSNH
conditions: T = 100 C, H
2
in hydrogenation of 6-methyl-5-hepten-2-one. Reaction
pressure = 40 bar.
2
According to our earlier studies, [10] the optimum conditions of
temperature and H pressure (100 C, 40 bar) for 6-methyl-5-
2
hepten-2-one hydrogenation were selected to evaluate the effect
of Zr doping. Data summarised in Fig. 8 show that the catalytic
activity, as well as the selectivity for the tested Ni-Zr bimetallic
catalyst (NiZr0.12TSNH
2
) and the one with higher amount of Zr
Table 1. Unbinding energies of monohydrogenation products out of the complex
(
NiZr0.18TSNH ), are nearly the same, independently on Zr
2
with catalyst models Ni13 and Ni13Zr that were used to represent NiTSNH
NiZrTSNH catalysts, respectively.
2
and
concentration. This suggests that Zr decorates specific sites on
Ni surface and once they are saturated the new Zr atoms will
coordinate on top of the already existing ZrO . Since these atoms
2
2
Catalyst model
Product unbinding energy [kcal/mol]
will have to direct contact with Ni they cannot affect its electronic
and/or geometric structures, and thus cause no significant
changes to the catalytic properties of the catalyst.
CC-hydrogenation
CO-hydrogenation
Ni13
45.2[a]
52.1
54.5[a]
64.0
Ni13Zr
[
a] Calculated with structures from Ref. 10
2
Addition of one H molecule to the activated substrate yields two
possible monohydrogenation products. Whereas for the Ni13
formation of both products is exothermic, zirconium doping makes
hydrogenation of C=O bond mildly uphill in energy (ΔE = +0.3
kcal/mol). Formation of C=C hydrogenation product is in both
cases exothermic (ΔE = -5.2 and -4.4 kcal/mol for Ni13 and Ni13Zr,
respectively). Energy spacing between the monohydrogenation
products interacting with the catalyst models is about 4 kcal/mol
for both catalysts studies and is smaller than energy spacing
between isolated hydrogenation products (ca. 13 kcal/mol).
Interestingly, unbinding energies of both possible products are
very different for the two catalyst models (see Table 1). Ni13Zr
interacts more strongly with the semihydrogeation products by
about 7 – 10 kcal/mol so that it eases double hydrogenation.
Figure 8. Comparison of the catalytic performance of the mono- and Zr-modified
catalysts. Reaction conditions: T = 100 C, H pressure = 40 bar.
2
Quantum chemical calculations revealed that zirconium atom
incorporates into the nickel lattice at the surface of model Ni13
species. The model adapted is analogous to the system adapted
for Ni-Sn studies before. [10] This outcome is in line with recent
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ChemCatChem
10.1002/cctc.202000235
FULL PAPER
Figure 9. Relative energies (incl. zero-point energies) of reactants, intermediates and products of monohydrogenation reaction of the 6-methyl-5-hepten-2-one.
Uncatalyzed reaction is shown for reference (left). In the presence of pure (represented with Ni13 structure) or Zr-doped (Ni13Zr) the complex is formed that undergoes
further hydrogenation reaction to form product bound to the catalyst molecule. Unbinding energies of the products are given in Table 1. Results for uncatalyzed and
Ni13-catalyzed reaction were taken from Ref. 10.
Conclusions
Herein, we extended the on-the-fly protocol to Zr modification of
parent Ni catalyst. The addition of zirconium led to a shift of the
catalytic selectivity to the fully hydrogenated product also via the
unsaturated alcohol reaction pathway, which is completely absent
in the parent catalyst. The effect of Zr contrasts with what has
Experimental Section
been observed with Sn, in which we observed a clear switch in
the thermodynamic order of the products. Comparison of XPS
data for mono- and Zr-doped catalyst suggests that zirconium
affects nickel electronic structure. According to theoretical
calculations, the interaction model of the substrate with the
catalyst species is similar for both undoped and doped catalysts,
i.e. the interaction occurs via both C=O and C=C bonds.
Additionally, Zr seems to gain a small positive charge while nickel
decreases slightly its charge making it better Lewis acid centre
than Ni and carbonyl oxygen prefer interaction with zirconium
atom over nickel atom, resulting in a significant increase of the
adsorption energy compared with the parent catalyst. It was also
noted that the increase of the substrate flow rate increased the
overall activity without affecting the process selectivity. This has
been rationalized based on reversible surface poisoning by the
substrate. On-the-fly modification coupled with spectroscopy and
theoretical calculations is a powerful tool to evaluate and
understand in real-time catalytic systems.
Preparation of the catalysts
Synthesis of NiTSNH : Nickel catalyst (NiTSNH ) was obtained at room
2
2
temperature conditions, during one-pot, two-step synthesis. Firstly, Ni
nanoparticles (Ni NPs) were collected by chemical reduction of Ni(II)
acetylacetonate (0.001 mol) with NaBH (molar ratio 1:2) in 65 ml of
4
ethanol. To prevent agglomeration of Ni NPs, tenfold excess of
trioctylophosphine oxide (TOPO) in relation to Ni was used. Synthesised
NPs of Ni were subsequently immobilised on the commercial amino group
2
terminated polymeric resin (TentaGel-S-NH , 5 g).
Synthesis of bimetallic Ni-Zr catalyst: Parent catalyst modification with
zirconium was conducted in the H-Cube Pro™ continuous-flow system by
surface organometallic modification chemistry (SOMC) methodology,
similar as it was done for our previous work.[10] Briefly, 0.15 g of NiTSNH
was loaded in the stainless-steel cartridge (70 mm long, 4 mm i.d.) and
pretreated for 1 h with 40 bar of hydrogen and ethanol flow. Subsequently,
a solution of bis(cyclopentadienyl)dimethylzirconium(IV) (ZrCp Me ) in
2 2
ethanol (3.1710-3 M) was flown through the cartridge at 100 C under 40
bar of hydrogen with a flow rate of 0.5 ml/min for 10 min resulting in the
2
2
preparation of NiZr0.12TSNH . The obtained bimetallic catalyst was used in
6-methyl-5-hepten-2-one hydrogenation immediately after the preparation.
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Catalysts characterisation
between 5 and 19 were considered. Cartesian coordinates of all relevant
structures are provided in the Supplementary Information.
The metals concentration, both in monometallic and bimetallic catalyst was
determined by atomic absorption spectrometry (AAS) after the dissolution
of the metals in aqua regia.
Transmission electron microscopy (TEM) experiments were carried out on
the electron microscope Titan G2 60 – 300 kV (FEI, Japan) equipped with
EDAX EDS (energy-dispersive X-ray spectroscopy) detector. Microscopic
studies of the catalysts were carried out at an accelerating voltage of the
electron beam equal to 300 kV. The samples were prepared by their
dispersing in pure alcohol using an ultrasonic cleaner and putting a drop
of this suspension on carbon films on copper grids.
Acknowledgements
This work was partially supported by grant from the National
Science Centre in Poland (OPUS 8, grant no. UMO-
2014/15/B/ST5/02094) and the Polish Ministry of Science and
Higher Education (IDEAS Plus II IdPII 2015000164). A.K.
acknowledges support from the National Science Centre, Poland,
grant number 2018/30/E/ST4/00004. Access to high performance
computing resources was provided by the Interdisciplinary Centre
for Mathematical and Computational Modelling in Warsaw,
Poland, under grants no. G64-9 and GB77-11.
Powder X-ray diffraction (PXRD) measurements were performed
employing Bragg-Brentano configuration. This type of arrangement was
provided using PANalytical Empyrean diffraction platform, powered at 40
kV × 40 mA and equipped with a vertical goniometer, with theta-theta
geometry using Ni filtered Cu Kα radiation. Data were collected in a range
of 2θ = 5 – 95°, with a step size of 0.008° and counting time 60 s/step.
The chemical composition and chemical state of the catalyst samples were
characterized by the X-ray photoelectron spectroscopy (XPS). XPS
spectra were measured in a Microlab 350 spectrometer (Thermo Electron)
using AlKα (hυ = 1486.6 eV, 300 W) as a source. Survey spectra and high-
resolution spectra were recorded using 100 and 40 eV pass energy,
respectively. A linear or Shirley background subtraction was made to
obtain XPS signal intensity. The peaks were fitted using an asymmetric
Gaussian/Lorentzian mixed function. Sample charging was corrected
Conflicts of interest
There are no conflicts to declare.
Keywords: Chemoselective flow hydrogenation • 6-methyl-5-
hepten-2-one • nano-Ni grafted on resin • on-the-fly catalyst
modification • zirconium surface modification
3
using C 1s sp signal (284.6 eV). The Ni and Zr signals were fitted using
orbital doublet separations reported by NIST database.[22]
6-Methyl-5-hepten-2-one hydrogenation on the bimetallic catalyst
[1] J. Yue, Catal. Today, 2018, 308, 3-19.
[
[
2] I. Rossetti, B. Catal. Today, 2018, 308, 20-31.
3] J. Sá, J. W. Medlin, ChemCatChem, 2019, 11, 3355-3365.
Catalytic hydrogenation on bimetallic catalyst was performed according to
the same procedure as for NiTSNH [10]
[4]
K. Masuda, T. Ichitsuka, N. Koumura, K. Sato, S. Kobayashi,
Tetrahedron, 2018, 74, 1705-1730.
2
using ThalesNano H-Cube Pro™
continuous-flow micro-reactor. 6-methyl-5-hepten-2-one solution in
ethanol (510-2 M) was flown through 0.15 g of a catalyst with a HPLC pump.
[5]
C. Paun, D. Giziński, M. Zienkiewicz-Machnik, D. Banaś, A. Kubala-
Kukuś, J. Sá, Catal. Commun., 2017, 92, 61-64.
®
The catalyst was placed in CatCart 70 cartridge. The hydrogen was
[
6] I. Goszwska, D. Giziński, M. Zienkiewicz-Machnik, D. Lisovytskiy, K.
Nikiforov, J. Masternak, A. Śrębowata, J. Sá, Catal. Commun., 2017
4, 65-68.
7] G. Vilé, N. Almora-Barrios, N. López, J. Pérez-Ramírez, ACS Catal.,
015, 5, 3767-3778.
generated in situ via water electrolysis. The catalytic reactions were
conducted with over a wide range of temperatures (25 – 100 C) and
pressures (10 – 60 bar) but constant reactant flow rate (0.5 ml/min).
Additionally, the flow rate influence on catalytic performance was analysed.
Hence, two additional flow rates of reagents were tested: 0.3 and 1 ml/min.
Substrate conversion and products formation were analysed by gas
chromatography (GC), namely a Bruker 456 GC equipped with FID
detector and non-polar BP-5 0.25 µm (5% phenyl, 95% dimethyl
polysiloxane) column.
,
9
[
[
2
8] D. Giziński, I. Goszewska, M. Zieliński, D. Lisovytskiy, K. Nikiforov, J.
Masternak, M. Zienkiewicz-Machnik, A. Śrębowata, J. Sá, Catal.
Commun., 2017, 98, 17-21.
[
[
9] D. Giziński, W. Błachucki, A. Śrębowata, M. Zienkiewicz-Machnik, I.
Goszewska, K. Matus, D. Lisovytskiy, M. Pisarek, J. Szlachetko, J. Sá,
ChemCatChem, 2018, 10, 3641-3646.
Quantum chemical calculations
10] M. Zienkiewicz-Machnik, I. Goszewska, A. Śrębowata, A. Kubas, D.
Giziński, G. Słowik, K. Matus, D. Lisovytskiy, M. Pisarek, J. Sá, Catal.
Today, 2018, 308, 38-44.
Computational strategy was described in details in our previous study of
nickel-tin catalyst.[10] Briefly, all computations were carried out within the
density functional theory as implemented in ORCA 4.2.0 suite of
[
[
[
[
[
11] J. P. Candy, B. Didillon, E. L. Smith, T. B. Shay, J. M. Basset, J. Mol.
Catal., 1994, 86, 179-204.
[
23]
programs. We employed PBE gradient-corrected exchange-correlation
functional[ that was augmented with a posteriori dispersion correction of
Grimme (D3).[25] Geometry optimizations and second derivative
calculations used compact def2-SVP basis set, while triple-ζ def2-TZVP
basis was chosen for single-point refinement.[26] All energy minima
possess only positive normal modes. Final reported energies are thus
PBE+D3/def2-TZVP and include zero-point energy correction. Global
energy minimum geometry search of the Ni13Zr catalyst model was
performed on the basis of Ni13 icosahedral minimum.[10] All multiplicities
12] L. Deghedi, J. M. Basset, J. P. Candy, J. A. Dalmon, A. C. Dubreuil, L.
Fischer, Chem. Engineer. Trans., 2009, 17, 31-36.
24]
13] S. V. Gribanova, Y. Y. Kharitonov, D. N. Dzhabarov, B. A. Rudenko, M.
T. Yanotovskii, Zh. Anal. Khim., 1990, 45, 1009-1016.
14] D. McGinty, C. S. Letizia, A. M. Api, Food Chem. Toxicol., 2010, 48,
S82-S83.
15] (a) S. O. Grim, L. J. Matienzo, W. E. Swartz Jr., J. Am. Chem. Soc.,
1
972, 94, 51165117; (b) G. Ertl, R. Hierl, H. Knozinger, N. Thiele, H. P.
Urbach, Appl. Surf. Sci., 1980, 5, 49-64.
This article is protected by copyright. All rights reserved.

ChemCatChem
10.1002/cctc.202000235
FULL PAPER
[
16] (a) K. S. Kim, N. Winograd, Surf. Sci., 1974, 43, 625-643; (b) L. Salvati,
L. E. Makovsky, J. M. Stencel, F. R. Brown, D. M. Hercules, J. Phys.
Chem., 1981, 85, 3700-3707; (c) K. Kishi, J. Electron Spectrosc. Relat.
Phenom., 1988, 46, 237-247.
[
[
17] (a) B. P. Loechel, H. H. Strehblow, J. Electrochem. Soc., 1984, 131,
7
13-723; (b) J. C. Klein, D. M. Hercules, J. Catal., 1983, 82, 424-441.
18] M. C. Biesinger, B. P. Payne, A. P. Grosvenor, L. W. M. Lau, A. R.
Gerson, Appl. Surf. Sci., 2011, 257, 2717-2730.
[
[
19] X. Yu, F. Zhang, W. Chu, RSC Adv., 2016, 6, 70537-70546.
20] W. Song, P. Ma, J. Wang, W. Zhang, Theor. Chem. Acc., 2020, 139,
2
8.
[
[
[
[
21] P. O. Löwdin, J Chem Phys, 1950, 18, 365.
‐
22] https://srdata.nist.gov/xps/main_search_menu.aspx.
23] F. Neese, WIREs: Comp. Mol. Sci., 2017, 8, 1, e1327.
24] J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett., 1996, 77, 3865-
3
868.
25] S. Grimme, J. Antony, S. Ehrlich, H. Krieg, J. Chem. Phys., 2010, 132,
54104.
26] F. Weigend, R. Ahlrichs, Phys. Chem. Chem. Phys., 2005, 7, 3297-
305.
[
[
1
3
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Entry for the Table of Contents (Please choose one layout)
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On-the-fly protocol to optimize
catalytic investigations by post-
synthetic modification of nano-Ni
catalyst morphology by
Małgorzata Zienkiewicz-Machnik*,
Ilona Goszewska, Damian Giziński,
Anna Śrębowata, Katarzyna
Kuzmowicz, Adam Kubas, Krzysztof
Matus, Dmytro Lisovytskiy, Marcin
Pisarek and Jacinto Sá*
introduction of zirconium is
presented. The addition of small
amounts of zirconium changes Ni
ability to reduce C=C bond and
significantly increases the
concentration of other
hydrogenation products, namely
saturated and unsaturated alcohol.
Page No. – Page No.
Tuning nano-nickel catalyst
hydrogenation aptitude by on-the-
fly zirconium doping
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