Ru/TiO2-catalysed hydrogenation of xylose: The role of the crystal structure of the support

Article abstract of DOI:10.1039/c5cy01005e

Effective dispersion of the active species over the support almost always guarantees high catalytic efficiency. To achieve this high dispersion, a favourable interaction of the active species with the support is crucial. We show here that the crystal structure of the titania support determines the interaction and consequently the nature of ruthenium particles deposited on the support. Similar crystal structures of RuO₂ and rutile titania result in a good lattice matching and ensure a better interaction during the heating steps of catalyst synthesis. This helps maintain the initial good dispersion of the active species on the support also in the subsequent reduction step, leading to better activity and selectivity. This highlights the importance of understanding the physico-chemical processes during various catalyst preparation steps, because the final catalyst performance often depends on the type of intermediate structures formed during the preparation.

Full text of DOI:10.1039/c5cy01005e

View Article Online
View Journal
Catalysis
Science &
Technology
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: C. Hernández-
Mejía, E. Raja, A. Olivos-Suarez, J. Gascon, H. F. Greer, W. Zhou, G. Rothenberg and R. N. Shiju, Catal. Sci.
Technol., 2015, DOI: 10.1039/C5CY01005E.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/catalysis

Please do not adjust margins
Catalysis Science & Technology
Page 1 of 8
View Article Online
DOI: 10.1039/C5CY01005E
Journal Name
ARTICLE
Ru/TiO2-catalysed hydrogenation of xylose: the role of crystal
structure of the support
Carlos Hernandez-Mejia,a Edwin S. Gnanakumar,a Alma Olivos-Suarez,b Jorge Gascon,b Heather
Greer,c Wuzong Zhou,c Gadi Rothenberga and N. Raveendran Shijua*
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
Effective dispersion of the active species over the support almost always guarantees high catalytic efficiency. To achieve
this high dispersion, favourable interaction of the active species with the support is crucial. We show here that the crystal
structure of the titania support determines the interaction and consequently the nature of ruthenium particles deposited
on the support. Similar crystal structures of RuO2 and rutile titania result in a good lattice matching and ensure a better
interaction during the heating steps of catalyst synthesis. This helps maintain the initial good dispersion of the active
species on the support also in the subsequent reduction step, leading to better activity and selectivity. This highlights the
importance of understanding the physico-chemical processes during various catalyst preparation steps, because the final
catalyst performance often depends on the type of intermediate structures formed during the preparation.
www.rsc.org/
compound in the food, cosmetics, and pharmaceutical
sectors.24-26 With an estimated market of $340M, xylitol is one
1. Introduction
of the most popular sweeteners.27 Moreover, its relative
inertness gives it a long shelf life, an important feature for
pharmaceutical preparations.28,29 Currently, xylitol is made via
catalytic hydrogenation over Raney nickel.30 Although this
catalyst is cheap, it deactivates quickly due to leaching and/or
Lignocellulosic biomass is an excellent feedstock for chemical
synthesis. It is renewable, abundantly available and does not
compete with food. Consequently, several groups are focused
on converting cellulose and hemicellulose into various
industrially important chemicals.1-12 Among these chemicals,
sugar alcohols attract particular interest, because of the strong
market demand from the food and nutraceuticals sectors.
Cellulose and hemicellulose can be hydrolysed using acid
catalysis into monomeric sugars, that are then hydrogenated
to sugar alcohols.13-15 Converting cellulose into C6 sugar
alcohols such as sorbitol and mannitol over supported metal
catalysts is well studied.16-21 Conversely, there are few reports
on converting hemicellulose into the corresponding C5 sugar
alcohols using solid catalysts.14, 22, 23 In this work, we focused
on the hydrogenation step from xylose (a hydrolysis product of
beechwood hemicellulose) to xylitol, an extensively used
poisoning.31, Any leached Ni must be removed, leading to
32
additional costs.27 Alternatively, one can use noble metals such
as Ru, Rh and Pd.33-37 Ru is the most effective, but it is much
more expensive than Ni, thus its efficiency and long-term
stability must be high to be a viable alternative.
For heterogeneous catalysts the active species such as the
metal is often supported on a high surface area metal oxide.
The interaction between metals and oxide supports, so-called
metal–support interactions, then becomes important.38
Tauster et al. proposed the concept of strong metal–support
interaction (SMSI) in 1978 to describe the drastic changes in
the chemisorption properties of Group 8–10 noble metals
supported on TiO2.39 Later, SMSI was widely observed in many
metal/oxide catalytic systems. Electronic or geometric factors
may be responsible for SMSI. Electronic factors would concern
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 2 of 8
View Article Online
DOI: 10.1039/C5CY01005E
ARTICLE
Journal Name
charge transfer between the metal and the oxide. As a result, recorded using a Gatan 794 CCD camera. This electron microscope
the electronic structure of the metal will be perturbed.
is also equipped with an Oxford Link ISIS SemiSTEM EDX system.
HPLC analyses were performed on an Agilent 1100 series
Here, we report the catalytic hydrogenation of xylose to xylitol instrument, equipped with a Rezex column (RPM-Monosaccharide
(Eq. 1) using Ru supported on TiO2. We show that the Pb+2) and a refractive index detector. Ultrapure water (type 1) was
deposition of Ru on TiO2 gives highly efficient catalyst. used as the mobile phase at a flow rate of 0.6 mL min-1 at 60 °C.
However, we also show that the efficiency depends Ruthenium chloride anhydrous (RuCl3) was purchased from Fluka.
significantly on the crystal structure of the support. The key Titanium dioxide (TiO2) from Hombikat (M311) was used as the
lies in the catalyst preparation steps, wherein the crystal support. D-(+)-xylose (≥99%), xylitol (≥99%), adonitol, and arabitol
structures of the support and RuO2 determine the mutual were purchased from Sigma-Aldrich. All the chemicals were used as
interaction and consequently the Ru particle size.
received.
2.2. Catalyst preparation
The Ru/TiO2 catalysts were prepared by wet-impregnation of four
different titania supports (Table 1). The commercial Hombikat
M311 titanium oxide is predominantly anatase (A). A second
anatase titania (B) support was prepared from the Hombikat M311
titanium oxide by calcination at 450 °C for 2 h. The third support
was rutile titania, obtained by calcining Hombikat M311 at 900 °C
for 24 hours (C). A support with both anatase and rutile phases was
also prepared from Hombikat M311 titanium oxide by calcination at
800 °C for 2 hours (D). Phase composition of each support was
determined by XRD (See ESI).
Eq.1. Xylose hydrogenation to xylitol
2. Experimental section
2.1. Materials and instrumentation
Powder X-ray diffractograms were recorded at ambient
temperature using a Rigaku Mini Flex II diffractometer with Ni-
filtered CuKα radiation (λ= 1.5406 Å) at operating parameters of 15
mA and 30 kV with step size 0.05° and speed of 5° min-1.
Temperature programmed reduction (TPR) studies were done using
a 1100 Series Thermo Electron Corporation TPDRO machine. A
heating rate of 5 °C min-1 was used with a 40 cm3 min-1 flow of 5%
H2/N2. The specific surface areas of samples were measured using
the BET (Thermo Scientific Surfer) method under N2 adsorptive gas
with multipoint modes at ‒196 °C. Scanning electron microscopy
(SEM) images were recorded without sputtering using a JEOL JSM-
6010LA with an accelerating voltage of 10 kV and a Everhart-
Thornley detector. SEM coupled with an energy dispersive X-ray
analysis (EDX) and equipped with a Silicon-drift detector confirmed
the elemental composition. Mapping analysis and element
detection where analysed with KLM markers of the characteristic X-
ray peak and a beam potential of 20 kV. A Backscattered-electron
detector (Semiconductor detector) was used to detect Ru particles
at a beam potential of 20 kV. Transmission electron microscope
(TEM) images were attained using a JEOL JEM-2011 electron
microscope operating at an accelerating voltage of 200 kV,
For each catalyst, RuCl3 (0.396mmol) , corresponding to 1wt% Ru
loading, was dissolved in deionized water (50 ml) in a round-bottom
flask and heated up to 75 ºC using an oil bath. Then titania (4 g) was
added into the RuCl3 solution under stirring and left at 75 ºC until
the water was completely evaporated. The samples were dried at
120 ºC for 12 h and were calcined at 400 ºC for 3 h. The samples
were then reduced at 350 ºC for 2 h under H2 atmosphere. The
samples were analysed by powder X-ray diffraction (see ESI).
Table 1. The properties of various Ru/TiO2 catalysts.
SSA* of
calcined reduced
catalysts catalysts
SSA of
Crystal
structure
Sample
Preparation
Hombikat M311
(Commercial
support)
A
B
C
Anatase
Anatase
Rutile
86
47
2
7
47
4
Hombikat
M311calcined at
450 °C, 2 h.
Hombikat M311
calcined at 900
°C, 24 h.
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 3 of 8
View Article Online
DOI: 10.1039/C5CY01005E
Journal Name
ARTICLE
Hombikat M311
calcined at 800
°C, 2 h.
Anatase supported Ru (
A
) gave a mixture of products, with low
Anatase
and rutile
D
14
12
xylitol selectivity. Interestingly, Ru supported on rutile titania
(catalyst ) gave 100% xylose conversion and up to 98% yield
for xylitol in 15 min. The catalyst showed similar behaviour to
C, indicating that the Ru properties are influenced by the rutile
part of the support. was more active and selective than
though still worse than rutile supported Ru. Note that is still
predominantly anatase, but has lower surface area
compared to . Thus, the surface area seems not to be critical
*SSA: Specific Surface Area (m2g-1)
C
D
2.3. Procedure for catalytic experiments
B
A,
B
The catalytic tests were carried out in 35 ml cylindrical stainless
steel autoclaves. In a typical catalytic test, 10 ml of xylose aqueous
solution (conc. ∼10 g L-1), 0.10g of catalyst and stirring bar were
placed in the autoclave. Then the autoclave was sealed, purged
three times with argon at room temperature and was pressurized
with H2 (20 bar). The autoclave was put in the heating block under
magnetic stirring and temperature was raised at a rate of 8 °C min-1
until reaching the desired temperature. After the reaction time, the
autoclave was rapidly cooled down by using an ice bath. Finally, the
reaction mixture was filtered and analysed by HPLC. The reaction
was carried out at three temperatures initially, 120, 140 and 160 °C.
From this, 120 °C was chosen as the optimal temperature and the
reaction was studied at different times: 15, 45, 120, 180 and 360
min.
a
A
here. The same trends in performance were observed at
140 °C and 160 °C, albeit that increasing temperature
decreased the xylitol yield (see Figure 1), giving instead more
of the diastereomers arabitol and adonitol.
Figure 2. Diastereomers of xylitol.
The kinetic studies at 120 °C (Figure 3) confirm that
C and D are
more active and selective than the anatase based catalysts
A
and
B
. Xylitol was selectively formed (98%) within 15 minutes
and . The selectivity decreased marginally with
3. Results and discussion
In a typical reaction (eq. 1), an aqueous solution of xylose was
over
C
D
increasing the reaction time.
A
does not show a major xylitol
, a maximum xylitol yield is
mixed with one of the Ru/TiO2 catalysts A–D (see Table 1) in a
yield at any given time. For
B
stainless steel autoclave at 120–160 °C under 20 bar hydrogen.
After the desired reaction time, the autoclave was quenched in
an ice bath and the products were analysed using HPLC.
observed at 180 min. Full conversion was not achieved with
both A and B under these conditions.
A recycling test for
C and D was carried out at 120 °C. The
reaction mixture after each time was centrifuged and the
liquid phase was separated from the catalyst. This liquid phase
was analysed and the catalyst was washed with distilled water.
Conversions and xylitol yields were constant even after the
fourth recycling test, showing the stability of these two
catalysts.
100
120 o
140 o
160 o
C
C
C
90
80
70
60
50
40
30
20
10
0
D
B
C
A
Figure 1. Xylitol yield at different temperatures after 3 h reaction. Reaction conditions:
20 bar H2, xylose:Ru ratio 100:1(w/w), solvent water.
Examining the substrate conversion and product yield at
120 °C, one sees immediately
a striking performance
difference between the anatase and rutile supports (Figure 1).
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 4 of 8
View Article Online
DOI: 10.1039/C5CY01005E
ARTICLE
Journal Name
Figure 4. TPR profiles for calcined Ru/TiO2 catalysts.
100
90
80
70
60
50
40
30
20
10
0
15 min.
45 min.
120 min.
180 min.
360 min.
SEM analysis (ESI) revealed a uniform dispersion of ruthenium
over after calcination as well as after reduction. In contrast,
EDX detected visible metallic agglomerations on the surface of
and , before and after reduction. We further studied the
C
A
B
catalysts by TEM, which provided important information
(Figure 5). The rutile TiO2 particles (Figure 5b) were of several
hundred nanometers in diameter. In contrast, the anatase TiO2
particles (Figure 5a) were smaller in size. Since the rutile form
was obtained by high temperature calcination, formation of
B
C
D
A
Figure 3. Xylitol yield during different reaction times at 120°C.
the larger titania particles is expected. Importantly,
homogeneous surface covering of Ru particles was observed
on rutile surface ( ). The typical Ru particle size is between 5-7
a
In order to explain the activity trends, we characterized the
catalysts by several techniques. The XRD patterns (See ESI)
confirmed that A and C are predominantly anatase and rutile
respectively. We also calculated the percentage of rutile phase in
each catalyst (B, C and D have 1.1%, 99.5% and 34.5% rutile phase,
respectively). Note that the most predominant crystallographic
plane for anatase is (101) and for rutile is (110).40 These planes
were used for calculating the ratio of the phases and for the images
shown in Figure 6. Diffraction peaks corresponding to ruthenium
species could not be observed, indicating high dispersion of
supported ruthenium. H2 TPR profiles of the calcined catalysts
(Figure 4) show a sharp peak between 180 and 230 °C, which can be
assigned to the reduction of RuO2. 36, 41, 42 Hydrogen intake from the
catalysts A, B, C and D are 1254, 1438, 739 and 507 ꢀg mol-1
respectively. Anatase-based catalysts have a higher hydrogen
consumption compared to rutile catalysts. The second peak on the
TPR profile (between 270 and 450 °C) may be ascribed to a partial
reduction of the support, inducing the formation of oxygen
vacancies or Ti3+ species.43
C
nm (see also ESI). On the contrary, Ru particles were very
localised on the anatase surface. These are much bigger (see
the dark particle in Figure 5a) and could easily be detected by
EDX (SEM images in ESI).
D
C
B
A
Figure 5. The TEM images of catalysts
A (a) and C (b) show the agglomeration of
100
200
300
400
the Ru on the anatase support.
Temperature ( )
oC
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 5 of 8
View Article Online
DOI: 10.1039/C5CY01005E
Journal Name
ARTICLE
The uniform distribution of Ru nanoparticles with a narrow size
distribution over rutile titania (C and D) suggests a lattice anchoring
interaction between Ru and the support. Since RuO2 also has a
rutile-type structure, we expect a high degree of lattice matching
between RuO2 and the rutile titania support, preventing the
agglomeration of Ru particles during the calcination step (Figure 6,
left).44-46 Since there is no such matching with the anatase support,
the RuO2 particles are less stable (Figure 6, right). Thus, the
agglomeration of Ru on anatase, as shown by TEM, can explain the
lower catalytic performance compared with rutile catalysts. RuO2
nanoparticles are reported to be easily aggregated in oxidative
atmosphere due to the volatility of oxidized ruthenium.47 This is the
case observed in the RuO2/anatase-TiO2. However, the intimate
interaction between RuO2 and rutile-TiO2, as a result of their high
degree of lattice matching stabilizes the RuO2 and maintains its high
dispersion during calcination and further reduction. The binding
nature of RuO2 nanoclusters on rutile TiO2 (110) and anatase TiO2
(101) surfaces was studied by first-principle calculations
previously.48 These studies showed that the adsorption energy of
RuO2 cluster on rutile is larger than that on anatase due to more
interfacial bonds formed between cluster and surface. This further
confirms our experimental observations that the rutile support
provides highly dispersed Ru with uniform nanosize, leading to high
activity and stability in xylose hydrogenation to xylitol. When the
support contains both rutile and anatase (D), the Ru is
predominantly present on the rutile. We observed such behaviour
previously for vanadia supported on Al2O3–MgO. Vanadium species
was preferentially attached to Al2O3 at low loadings and to MgO at
high loading.49
Figure 6. Atomic structures of RuO2 on rutile (left) and anatase (right) TiO2 showing the
high degree of lattice matching of RuO2 on rutile TiO2 (created by viewerlite software).50
Based on the information from electron microscopy and TPR, we
can also infer that large Ru species on anatase TiO2 leads to a higher
reducibility of the support. As mentioned before, the peak between
270 and 450 °C in the TPR of anatase-based catalysts may be
ascribed to a partial reduction of the support, inducing the
formation of oxygen vacancies and Ti3+ species.43 This could happen
most likely at the interface between the Ru species and TiO2
support. These species have two main effects. First they alter the
charge transfer between the metal and its support leading to
51, 52
changes on the catalyst’s performance.
Second, the presence
of Ti3+ species interacting with the C‒O bond has been related in
53
previous studies34, with either a hydrogenolysis pathway where
this C‒O bond is cleaved or as a Lewis base leading to a retro-aldol
reaction (Figure 7). Thus, the production of glycols by anatase based
catalysts can be explained. Moreover, the surface is deficient in
We also analysed the catalysts after the reaction by XRD and TEM.
The peak at 2θ=25° was slightly broader for the spent A catalyst.
There was no other major change in the XRD patterns before and
after the reaction for any of the catalysts (Fig. S2). TEM images did
not show any obvious changes for the spent catalysts (see ESI). The
Ru particles are small and highly dispersed for the spent catalyst C
as in the fresh catalysts. This indicates that the structure remains
unchanged during the reaction. Indeed, this catalyst retained the
same level of activity after multiple recycling tests.
oxygen, leading to aldehyde decomposition in favour of oxygen
55
restoration at the lattice, forming different by-products.54,
All
these effects collectively lead to a lower selectivity for the anatase-
supported Ru catalysts.
Figure 7. Ti3+ acting as a Lewis base for xylose retro-aldol reaction to glycols.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 6 of 8
View Article Online
DOI: 10.1039/C5CY01005E
ARTICLE
Journal Name
15.
W. Y. Lim and J. Dumesic, Angew. Chem. Int. Ed., 2013, 52,
1270-1274.
Conclusions
16.
17.
P. L. Dhepe and A. Fukuoka, Catal. Surv. Asia 2007, 11, 186.
M. Yabushita, H. Kobayashi and A. Fukuoka, Appl. Catal. B,
2014, 145, 1-9.
Y.-B. Huang and Y. Fu, Green Chem., 2013, 15, 1095-1111.
A. M. Ruppert, K. Weinberg and R. Palkovits, Angew. Chem. Int.
Ed., 2012, 51, 2564-2601.
R. Palkovits, K. Tajvidi, J. Procelewska, R. Rinaldi and A.
Ruppert, Green Chem., 2010, 12, 972-978.
A. Fukuoka and P. L. Dhepe, Angew. Chem. Int. Ed., 2006, 45,
5161-5163.
F. Cherubini and A. H. Strømman, Biofuels, Bioprod. Bioref.,
2011, 5, 548-561.
S. Dutta, RSC Adv., 2012, 2, 12575-12593.
C. Hayes, J. Dent. Educ., 2001, 65, 1106-1109.
K. Mäkinen, J. Appl. Nutr., 1992, 44, 16–28.
M. Uhari, T. Kontiokari, M. Koskela and M. Niemelä, Br Med J.,
1996, 313, 1180–1184.
M. Yadav, D. K. Mishra and J. S. Hwang, Appl. Catal. A 2012,
425– 426, 110– 116.
S. S. Schiffman and C. A. Gatlin, Neurosci. Biobehav. R., 1993,
Ru/TiO2 is an effective catalyst for xylose hydrogenation to
xylitol. However, care should be taken in preparing the
catalyst, as the crystal structure of TiO2 support has a strong
influence on the efficiency of the final catalyst. Thus,
ruthenium supported on rutile titania gives high conversion as
well as high selectivity to xylitol, in spite of a low surface area,
while Ru on anatase is less active and non-selective. TEM
analysis revealed well dispersed Ru particles, 5–7 nm size over
the rutile-titania whereas bigger Ru agglomerations were
found on anatase TiO2. This can be explained by a high degree
of lattice matching for rutile since RuO2 also has a rutile-type
structure, preventing mobility of Ru particles during heating
treatments. Small dispersed Ru particles mean more active
centres for hydrogenation, improved charge transfer with the
support and easier reduction of any superficially oxidised
ruthenium. Additionally, possible formation of Ti3+ species over
anatase based catalysts may serve as Lewis base sites
modifying the reaction pathway and thus contributing further
to the lack of selectivity. This work shows the importance of
understanding the intermediate steps in the catalyst synthesis
process.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
17, 313-345.
H. Förster, H. L. Sipple and K. W. McNutt, Sugars in Nutrition,
Academic Press, New York, 1974.
Finland Pat., FI 589388, 1981.
J. P. Mikkola and T. Salmi, Chem. Eng. Sci., 1999, 54, 1583-
1588.
J. P. Mikkola and T. Salmi, Catal. Today, 2001, 64, 271–277.
J. Wisniak, M. Hershkowitz and S. Stein, Ind. Eng. Chem., Prod.
Res. Develop., 1974, 13, 232-236.
30.
31.
32.
33.
34.
C. Newman, X. Zhou, B. Goundie, I. T. Ghampson, R. A.
Pollock, Z. Ross, M. C. Wheeler, R. W. Meulenberg, R. N. Austin
and B. G. Frederick, Appl. Catal. A-Gen., 2014, 477, 64-74.
M. Besson, P. Gallezot, A. Pigamo and S. Reifsnyder, Appl.
Catal. A, 2003, 250, 117-124.
Acknowledgements
CHM thanks the National Council of Science and Technology,
Mexico (Consejo Nacional de Ciencia y Tecnología CONACyT)
for financial support (Scholarship 216968). WZ and HFG thank
the EPSRC for a Platform grant (EP/K015540/1). This work is
part of the Research Priority Area Sustainable Chemistry of the
UvA, http://suschem.uva.nl
35.
36.
37.
J. W. da-Silva and A. J. G. Cobo, Appl. Catal. A, 2003, 252, 9-16.
S. J. Tauster, S. C. Fung and R. L. Garten, J Am. Chem. Soc.,
1978, 100, 170-175.
N. R. Shiju, ChemCatChem, 2011, 3, 112-114.
S. J. Tauster, Acc. Chem. Res., 1987, 20.
38.
39.
40.
K. Sivaranjani and C. S. Gopinath, J. Mater. Chem., 2011, 21,
2639-2647.
41.
42.
43.
44.
T. Omotoso, S. Boonyasuwat and S. P. Crossley, Green Chem.,
2013, 16, 645-652.
B. D. McNicol and R. T. Short, J. Electroanal. Chem., 1978, 92,
115-120.
T. Ekou, L. Ekou, A. Vicente, G. Lafaye, S. Pronier, C. Especel
and P. Marecot, J. Mol. Catal. A, 2011, 337, 82-88.
J. M. G. Carballo, E. Finocchio, S. Garcia, S. Rojas, M. Ojeda, G.
Busca and J. L. G. Fierro, Catal. Sci. Technol., 2011, 1, 1013-
1023.
J. Li, G. Lu, G. Wu, D. Mao, Y. Guo, Y. Wang and Y. Guo,
Catal. Sci. Technol., 2014, 4, 1268-1275.
G. A. Rizzi, A. Magrin and G. Granozzi, Phys.Chem.Chem.Phys.,
1999, 1, 709-711.
Y. Zhang, X. Wang, Y. Zhu and T. Zhang, Appl. Catal. B, 2013,
129, 382-393.
Notes and references
1.
2.
W. Keim, Pet. Chem., 2010, 50, 298-304.
T. Werpy and G. Petersen, Top value added chemicals from
biomass, volume I: results of screening for potential candidates
from sugars and synthesis gas, Pacific Northwest National
Laboratory, 2004.
3.
4.
5.
6.
7.
8.
B. Kamm, P. R. Gruber and M. Kamm, Biorefineries – Industrial
Processes and Products, Wiley-VCH, Weinheim, 2006.
R. Beerthuis, M. Granollers, D. R. Brown, H. J. Salavagione, G.
Rothenberg and N. R. Shiju, RSC Adv., 2015, 5, 4103-4108.
Z. Strassberger, F. van der Klis, D. S. van Es, S. Tanase, P.
Prinsen and G. Rothenberg, Green Chem., 2015, 17, 325-334.
E. V. Ramos-Fernandez, N. J. Geels, N. R. Shiju and G.
Rothenberg, Green Chem., 2014, 16, 3358-3363.
P. Demma Carà, R. Ciriminna, N. R. Shiju, G. Rothenberg and M.
Pagliaro, ChemSusChem, 2014, 7, 835-840.
V. Subbiah, P. van Zwol, A. C. Dimian, V. Gitis and G.
Rothenberg, Top. Catal., 2014, 57, 1545-1549.
45.
46.
47.
48.
49.
50.
51.
52.
H. Dong, L. Zhang and X. Zhou, Theor. Chem. Acc., 2014, 133,
1-9.
Z. Strassberger, E. V. Ramos-Fernandez, A. Boonstra, R. Jorna, S.
Tanase and G. Rothenberg, Dalton Trans., 2013, 42, 5546-5553.
G. W. Watson, E. T. Kelsey, N. H. de Leeuw, D. J. Harris and S.
C. Parker, J. Chem. Soc., Faraday Trans., 1996, 92, 433.
Z. Jiang, W. Zhang, L. Jin, X. Yang, F. Xu, J. Zhu and W. Huang,
J. Phys. Chem., 2007, 111, 12434-12439.
S. Fischer, F. Schneiderb and K.-D. Schierbaum, Vacuum, 1996,
47, 1149-1152.
K. Kreuzer and R. Kramer, J. Catal., 1997, 167, 391-399.
H. Idriss, K. S. Kim and M. A. Barteau, Surf. Sci., 1992, 262, 113-
127.
9.
A Corma and P. Serna, Science, 2006, 313, 332.
10.
M. Dusselier, M. Mascal and B. F. Sels, Top. Curr. Chem., 2014,
353, 1-40.
11.
12.
13.
14.
I. Delidovich, K. Leonhard and R. Palkovits, Energy Environ.
Sci., 2014, 7, 2803-2830.
C. Caro, K. Thirunavukkarasu, M. Anilkumar, N. R. Shiju and G.
Rothenberg, Adv. Synth. Catal., 2012, 354, 1327-1336.
P. Maki-Arvela, T. Salmi, B. Holmbom, S. Willfor and D. Y.
Murzin, Chem. Rev., 2011, 111, 5638-5666.
P. Demma Carà, M. Pagliaro, A. Elmekawy, D. R. Brown, P.
Verschuren, N. R. Shiju and G. Rothenberg, Catal.Sci.Technol.,
2013, 3, 2057-2061.
53.
54.
55.
G. Lu, A. Linsebigler and J. T. Yates, J. Phys. Chem., 1995, 99,
7626-7631.
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Catalysis Science & Technology
Page 7 of 8
View Article Online
DOI: 10.1039/C5CY01005E
Journal Name
ARTICLE
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Catalysis Science & Technology
Page 8 of 8
Lattice matching holds the secret to the Ru-
catalysed hydrogenation of xylose to xylitol, a
key reaction in practical biomass conversion.