Effect of organic template removal approaches on physiochemical characterization of Ni/Al-SBA-15 and eugenol hydrodeoxygenation

Article abstract of DOI:10.1016/j.jssc.2019.121063

Template removing approaches can significantly impact the physiochemical properties of mesoporous molecular sieve materials. In order to better understand the relationship between template removing approaches and the properties of Ni/Al-SBA-15, four kinds of template removing approaches were introduced to remove the organic template from Al-SBA-15, respectively. The structural characteristics of these materials were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray fluorescence (XRF), powder X-ray diffraction (XRD), N₂-sorption, Fourier transform infrared spectra (FT-IR), infrared spectra of pyridine adsorption (Py-FTIR), magic angle spinning-nuclear magnetic resonance (MAS-NMR), X-ray photoelectron spectroscopy (XPS) and gas chromatography-mass spectrometry (GC-MS). Ni/Al-SBA-15 of which the organic template was removed by two-step calcination method had the maximum specific surface area (619 ?m²/g). In contrast, Ni/Al-SBA-15 of which the organic template was removed using solvent extraction approaches had the lowest specific surface area (555 ?m²/g). The mesopore diameter of Ni/Al-SBA-15, using electric heating digestion method to remove the template, was significantly increased and the wall thickness was significantly decreased to 11.62 ?nm in comparison with the other samples. The selectivity of products during the process of eugenol hydrodeoxygenation was investigated. High hydrocarbons were obtained during catalytic hydrodeoxygenation over Ni/Al-SBA-15 of which the organic template was removed by using solvent extraction approaches. Compared with direct calcination process, two-step calcination was more effective in removing template and the corresponding catalyst was much more suitable for the hydrodeoxygenation process.

Full text of DOI:10.1016/j.jssc.2019.121063

Journal Pre-proof
Effect of organic template removal approaches on physiochemical characterization of
Ni/Al-SBA-15 and eugenol hydrodeoxygenation
Xiangping Li, Han Yin, Jianguang Zhang, Juping Liu, Guanyi Chen
PII:
S0022-4596(19)30568-7
DOI:
https://doi.org/10.1016/j.jssc.2019.121063
YJSSC 121063
Reference:
To appear in: Journal of Solid State Chemistry
Received Date: 17 September 2019
Revised Date: 12 November 2019
Accepted Date: 12 November 2019
Please cite this article as: X. Li, H. Yin, J. Zhang, J. Liu, G. Chen, Effect of organic template removal
approaches on physiochemical characterization of Ni/Al-SBA-15 and eugenol hydrodeoxygenation,
Journal of Solid State Chemistry (2019), doi: https://doi.org/10.1016/j.jssc.2019.121063.
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Effect of organic template removal approaches on physiochemical
characterization of Ni/Al-SBA-15 and eugenol hydrodeoxygenation
Xiangping Li1, 2, Han Yin1, Jianguang Zhang3,*, Juping Liu1, Guanyi Chen1, 4
1 China-Australia Centre for Sustainable Urban Development/School of Environmental Science and
Engineering, Tianjin University, Tianjin 300072, China;
2Qingdao Institute for Ocean Technology of Tianjin University, Qingdao 266235, China;
3 School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong
266580, China;
4 Tianjin Key Lab of Biomass/Wastes Utilization, Tianjin 300354,China
*Corresponding authors.. E-mail addresses: eduzjg@163.com
Abstract
Template removing approaches can significantly impact the physiochemical
properties of mesoporous molecular sieve materials. In order to better understand the
relationship between template removing approaches and the properties of
Ni/Al-SBA-15, four kinds of template removing approaches were introduced to
remove the organic template from Al-SBA-15, respectively. The structural
characteristics of these materials were analyzed by transmission electron microscopy
(TEM), scanning electron microscopy (SEM), X-ray fluorescence (XRF) , powder
X-ray diffraction (XRD), N2-sorption, Fourier transform infrared spectra (FT-IR),
infrared spectra of pyridine adsorption (Py-FTIR), magic angle spinning-nuclear
magnetic resonance (MAS-NMR), X-ray photoelectron spectroscopy (XPS) and gas
chromatography-mass spectrometry (GC-MS). Ni/Al-SBA-15 of which the organic
template was removed by two-step calcination method had the maximum specific
surface area (619 m2/g). In contrast, Ni/Al-SBA-15 of which the organic template was

removed using solvent extraction approaches had the lowest specific surface area (555
m2/g). The mesopore diameter of Ni/Al-SBA-15, using electric heating digestion
method to remove the template, was significantly increased and the wall thickness
was significantly decreased to 11.62 nm in comparison with the other samples. The
selectivity of products during the process of eugenol hydrodeoxygenation was
investigated. High hydrocarbons were obtained during catalytic hydrodeoxygenation
over Ni/Al-SBA-15 of which the organic template was removed by using solvent
extraction approaches. Compared with direct calcination process, two-step calcination
was more effective in removing template and the corresponding catalyst was much
more suitable for the hydrodeoxygenation process.
Keywords:
Ni/Al-SBA-15, template removing approaches, hydrodeoxygenation, eugenol
1. Introduction
In recent years, materials with different structure have attracted extensive
attention, especially for mesoporous materials [1-5]. With high specific surface area,
regular and tunable pore size, large pore volume, as well as stable and interconnected
framework, mesoporous materials have great potential to be applied in heterogeneous
catalysis [6], bio-adsorption [7], separation [8], drug delivery [9], sensing [10, 11] as
well as optical and electronic uses [12]. Since MCM-41 was synthesized by BECK
using quaternary ammonium supramolecular surfactant as template, mesoporous
materials entered a new stage of development, especially in the field of catalysis [13,
14]. Mesoporous materials has been widely used in aromatization [15, 16],
hydrodesulfurization and hydrodeoxygenation [17, 18]. The pore structure and
hydrothermal properties of mesoporous material can be improved by changing the
synthesis method and post-treatment method [19].

SBA-15 with stable skeleton structure is one kind of silica-based mesoporous
material. For SBA-15, the specific surface area can reach to 1000 m2/g, the pore wall
thickness is about 6 nm, and the molecular surface contains a large number of silanol
groups make SBA-15 become an ideal catalyst carrier [20]. Al-SBA-15 with large
specific surface area, large pore diameter and pore volume can be obtained by adding
aluminium source during synthesis process. The unique structure, surface
characteristics, good thermal stability and mechanical strength make Al-SBA-15 have
higher catalytic activity than those of traditional alumina catalysts during the reaction.
It is effective to prepare Al-SBA-15 using hydrothermal synthesis process by adding
organic template agent.
However, organic templates which occluded within the pores of Al-SBA-15
should be removed before application [21]. Only the template agent is removed from
the original network structure, can the ideal ordered mesoporous materials be obtained
[22]. Various methods have been explored to remove organic template from the
precursor of the synthesized porous materials. The most commonly used organic
templates removing methods are calcination and solvent extraction (by conventional
solvent) [23, 24]. The organic template can be completely removed by using
calcination method, but the structure of materials can also be contracted or collapsed
after calcination. Moreover, a large amount of CO2 and organic amine mixture are
produced [25]. He et al. reported that when two-step calcination method was used to
remove the organic template, MCM-41 with a better long-range structure and larger
quantities of acid sites was obtained in comparison with MCM-41 prepared by
directly calcination process at high temperature [26]. Solvent extraction can preserve
the skeleton structure of the material to a great extent while recycling expensive
organic agents, however the removal of the organic template was not complete [27].

Ultraviolet decomposition method [28] and ozone oxidation method [29] were also
used to remove the organic template from porous materials, which can remove the
template at a relatively low temperature, and the damage to the hole is less. But the
processing amount is very limited at a time, thus long processing time is needed, and
the operating conditions are complex [27]. Supercritical carbon dioxide extraction is
another method, which is high-efficiency and environment-friendly [30]. However,
due to the harsh operation, high operating cost and requirement for expensive
equipment, the wide application of this method is limited. Microwave-assisted method
has also been used in removing templates [21, 31]. This method can quickly remove
the templating agent from mesoporous materials. But the removal conditions of the
microwave-assisted method are difficult to control for some mesoporous materials
[31]. Template removing method have a great influence on the structural stability of
the mesoporous material and the silanol groups on the surface of the mesoporous
material. However, the impact of these methods on the physiochemical properties of
Al-SBA-15 and the corresponding catalytic activity of Al-SBA-15 supported catalysts
has not been deeply investigated.
Nickel as one kind of transition metal with unique properties has been widely
used in catalysts [32-34]. Ni/Al-SBA-15 is regarded as one of the most promising
catalysts to be used in bio-oils refining processes such as hydrodeoxygenation (HDO),
cracking and so on [35, 36]. Due to the complex composition of bio-oil and its
instability, investigation of bio-oil upgrading by HDO directly is challenged. Eugenol
as one of the model compounds of bio-oil has been used to develop highly active and
selective hydrodeoxygenation catalysts [35, 37].
In this study, four kinds of template removing methods were introduced to
remove the template existing in Al-SBA-15 precursor. Ni/Al-SBA-15 is synthesized

and used as catalyst for eugenol hydrodeoxygenation. Nickel species were loaded
onto Al-SBA-15 by using incipient wetness impregnation method. The effects of
different template removing methods on the physiochemical characteristics of
Al-SBA-15 and Ni/Al-SBA-15, and on the eugenol hydrodeoxygenation activity in
liquid phase over Ni/Al-SBA-15 were investigated.
2. Materials and methods
2.1. Materials
Pluronic P123 (EO20-PO70-EO20) was purchased from Sigma-aldrich company.
Tetraethyl orthosilicate (TEOS, AR) was purchased from Sinopharm Chemical
Reagent company. Aluminium nitrate 9-hydrate (AR, Al(NO3)3·9H2O), nickel nitrate
hexahydrate (98 %), p-cresol (≥ 99.7 %) and eugenol (99 %) were purchased from
Aladdin Chemical company. n-dodecane (AR) was purchased from Tianjin Kermel
Chemical company. All the chemicals were used as received.
2.2. Preparation of Al-SBA-15 precursors
Al-SBA-15 precursor was synthesized by using P123 as polymeric template
according to the method reported [35, 38]. At the first step, 1.0 g of Pluronic P123
was put in a glass beaker with volume of 150 mL. Then, 80 mL of deionized water
was added into the above beaker and stirred to dissolve the Pluronic P123. Thirdly,
0.41 g of Al(NO3)3·9H2O was put into the mixture and stirred magnetically until
completely dissolved. Afterwards, 7.3 mL of TEOS was added into the above mixture,
followed by vigorous magnetic stirring for 15 h at room temperature, and then at 313
K for 24 h. Afterwards, the obtained mixture was transformed into the hydrothermal
synthesis reactor at 363 K for 2 days. Finally, the solid product in the bottom of

reactor was filtered, washed with distilled water, and put in an oven for drying at 333
K overnight in air.
2.2. Methods for removing the template of Al-SBA-15 precursors
The template of Al-SBA-15 precursor was removed by different methods,
including the direct calcination, two-step calcination, solvent extraction and electric
heating digestion method. In direct calcination process, Al-SBA-15 precursor in
square crucible was firstly put into a muffle furnace and heated from room
temperature to 823 K with a heating rate of 3 K/min, and held at this temperature for 5
h. The obtained Al-SBA-15 was named as SC1 for short in this paper. In two-step
calcination process, Al-SBA-15 precursor in square crucible was firstly put into a
muffle furnace for heating from room temperature to 373 K with a heating rate of 3
K/min and held at this temperature for 2 h, followed by heating from 373 K to 823 K
with a heating rate of 3 K/min and held at this temperature for 5 h. The obtained
Al-SBA-15 was named as SC2 for short in this paper. In the solvent extraction
process, Al-SBA-15 precursor was dried at 353 K for 24 h to evaporate water. Then, 6
g of Al-SBA-15 precursor was added into a round-bottom flask containing 250 mL of
ethanol. The template was removed by using a Soxhlet system for 6 h. After
extraction, the samples were filtrated and dried at 353 K for 12 h, resulting in the
formation of Al-SBA-15 named as SE for short in this paper. The electric heating
digestion process was as follows. (1) 5.83 mL of HNO3 was solved in 5.17 mL of
water, then 4 mL of H2O2 (30%) was added to the solution; (2) 1 g of Al-SBA-15
precursor was added into the above solution; (3) the mixture was poured into a PTFE

digestion tube and sealed, then the PTFE digestion tube was put into an electric
digestion apparatus (Hanon, SH230) at 600 w and 423 K for 15 min; (4) After
filtration, the solid was washed with deionized water until to pH=7; (5) the solid
material was put in an oven at 363 K overnight, resulting in the formation of
Al-SBA-15 named as SD for short in this paper.
Incipient wetness impregnation method was applied to load nickel species onto
Al-SBA-15. The process was proceeded as according to the method reported in
reference using ethanol as the impregnant and using nickel nitrate hexahydrate as
nickel source [35]. SC1, SC2, SE and SD was respectively named as NSC1-C,
NSC2-C, NSE-C and NSD-C after loading nickel species and calcination. Before
reaction, Ni/Al-SBA-15 was reduced under H2 and N2 atomosphere (3:7) at 100
mL/min and kept at 823 K for 2 h with a heating rate of 3 K/min. Samples after
reduction were named as NSC1-R, NSC2-R, NSE-R and NSD-R, respectively.
2.3. Catalyst characterization
Hitachi S-4800 SEM-microscope was used to measure the SEM images of
samples. TEM images were taken by a Hitachi FB-2100 FIB apparatus. Before TEM
measurement, a drop of an ultra-sonicated methanol-sample mixed suspension was
deposited onto a carbon-coated Cu grid. The measurement of nitrogen sorption
isotherms of samples were carried out at 77 K by using a physical sorption instrument
(Micromeritics ASAP 2460). Samples were outgassed at 423 K for 3 h before
adsorption measurements. Brunauer-Emmett-Teller (BET) model was introduced to
calculate the total specific surface areas of the samples, and t-plot method was used to

calculate the micropore volume and the external specific surface area of the samples.
The non-local density functional theory (NLDFT) was introduced to analyze the
mesopore diameter. The crystal structure of samples was analyzed by XRD patterns
which were obtained by using a Bruker D8 Advance diffractometer with Cu Kα
radiation. The XRD patterns were accumulated within the wide-angle range of 20-70°
(2θ) and small-angle the range of 0-5° (2θ). XPS measurements of samples were
taken by a X-ray photoelectron spectrometer (ThermoFischer, ESCALAB 250Xi, Al
Kα radiation (hv=1253.6 eV)). The binding energies (BE) of elements in samples
were calibrated by referring to the BE of C 1s peak at 284.60 eV. XRF spectrometer
(Axios PW4400, Panalytical) was used to detect Si to Al ratio and nickel content of
29
the Ni/Al-SBA-15. Si MAS-NMR spectra were collected by the solid state nuclear
magnetic resonance spectrometer (Infinityplus 300, Varian). FT-IR spectra of samples
were collected by a FT-IR spectrometer (Nicolet, Nexus 410) at room temperature.
Before detection, samples were mixed with KBr, ground thoroughly and compressed
into self-supporting wafers. Then, the FT-IR spectra of samples were collected within
wavenumber range of 2000 to 400 cm-1 with resolution of 4 cm-1. The distribution,
strength and type of acid sites were calculated by Py-FTIR on a FTIR spectrometer
(Thermo Nicolet 380).
2.4. Catalytic conversion of eugenol
Eugenol hydrodeoxygenation over different Ni/Al-SBA-15 in liquid phase was
carried out in an autoclave reactor with internal volume of 100 mL. Before reaction,
770 µL of eugenol, 40 mL of n-dodecane and 0.05 g of Ni/Al-SBA-15 were put into

the reactor. 0.1 Mpa of H2 was used to flush the reactor for three times and eugenol
hydrodeoxygenation was took place at 513 K for 2 h under stirring speed of 680 rpm.
After reaction, the liquid product was separated and put in glass bottles and sealed.
The catalyst was dried at 373 K overnight, weighed and recorded. All products were
analyzed by GC-MS (Agilent 7890A/5975C) and p-cresol was used as an internal
standard during the detect process.
3. Results and discussion
3.1. Characterization of the samples
In order to obtain the mesostructure of Ni/Al-SBA-15, small-angle powder XRD
was introduced. The XRD patterns of samples are shown in Fig. 1. Three
characteristic peaks, namely (100), (110) and (200), appeared in the XRD patterns of
all the samples. This indicated that all Ni/Al-SBA-15 samples had an ordered
two-dimensional (2D) hexagon structure, which is very consistent with the topology
pattern of SBA-15. The (100) plane of NSD-C moved to lower angle of 2θ due to the
increase of lattice spacing(d) after removing the organic template [39].
NSD-C
NSE-C
NSC2-C
NSC1-C
0.7
1.7
2.7
3.7
2θ/º
Fig. 1. Small-angle Powder X-ray diffraction patterns after calcination.

The nitrogen sorption isotherms and pore size distribution curves of NSC1-C,
NSC2-C, NSD-C and NSE-C are as shown in Fig. 2. All the samples showed typical
IV type isotherms of IUPAC classification (Fig. 2a). In addition, due to the capillary
condensation phenomenon, hysteresis loops were observed in the IV type isotherms
[40]. The hysteresis loops presented in the desorption branch of the calcined samples
were divided into two steps. The first step was the desorption process within the range
fron 0.75 to 0.61 p/p0 on the desorption branch, which was corresponded to the
nitrogen desorption from the “open” mesopores. The second step was the desorption
process within the range from 0.61 to 0.47 p/p0, which was corresponded to the N2
adsorption in the “blocked” mesopores [38, 41, 42]. This indicates that NSC2-C and
NSE-C had larger ratio of “open” mesopores than the other two samples. The NLDFT
pore size distribution curves of samples are shown in Fig. 2b. It could be seen that the
pore size distribution of NSD-C was moved to higher diameter. The parameters such
as pore diameter, pore volume and specific surface area of samples are as shown in
Table 1. The Si to Al ratios maintained within range of 60-64 for NSC1-C, NSC2-C
and NSE-C. However, the Si to Al ratio of NSD-C was up to 844, which was caused
by aluminum leaching during the template removal process by using electric heating
digestion methods. The nickel contents of samples were within the range of
17.6-20.4 %. The specific areas of samples were in the order of
NSC2-C>NSC1-C>NSD-C>NSE-C. NSC2-C had the largest specific surface area
(619 m2/g); while NSE-C had the lowest (555 m2/g). NSC1-C, NSC2-C and NSE-C
had approximately the same mesopore diameter, which was about 6.1 nm. While for
NSD-C, the mesopore diameter was up to 6.68 nm. The wall thickness of NSC1-C,
NSC2-C and NSE-C was about 12.2 nm. In contrast, the wall thickness of NSD-C
was significantly decreased to 11.62 nm. In combined with the shape of hysteresis

loops appearing in the adsorption-desorption isotherms, it can be deduced that the part
of the ordered pore structure in NSD-C was destroyed after removal of organic
templates by using electric heating digestion methods.
a
b
NSD-C
NSD-C
NSE-C
NSC2-C
NSC1-C
NSE-C
NSC2-C
NSC1-C
4
6
8
10
12
0
0.2
0.4
0.6
0.8
1
p/p0
PSD/nm
Fig. 2. (a) nitrogen adsorption-desorption isotherms at 77 K determined on calcined Ni based
Al-SBA-15 samples with different organic template removal approaches and (b) NLDFT pore
size distribution curves calculated from adsorption branches of calcined Ni based Al-SBA-15
samples with different organic template removal approaches.
Table 1 The structural properties of Ni/Al-SBA-15 samples with different organic template
removal approaches from N2 sorption and XRD data.

Sample
Si/Ala Ni/%a
ABET
Vp
Vmic
Vmes
a0
Dp
t
(nm)
(m2/g) (cm3/g) (cm3/g) (cm3/g)
(nm)
(nm)
NSC1-C
NSC2-C
NSE-C
64
60
17.6
18.4
20.4
20.2
574
619
555
571
0.552
0.584
0.568
0.687
0.103
0.118
0.091
0.048
0.448
0.465
0.477
0.640
18.3 6.12
18.3 6.11
18.3 6.11
18.3 6.68
12.18
12.19
12.19
11.62
63
NSD-C
844
a, the Si to Al ratios and the nickel content were obtained by XRF. ABET- total specific surface area
obtained by the BET method. Vp-total pore volume of single point adsorption at p/p0= 0.995. Aext
and Vmic-external specific surface area and micropore volume obtained by the t-plot method.
Vmes-mesopore volume, calculated as Vmeso=Vtotal-Vmicro. a0- unit cell parameter determined by
XRD. Dp-mesopore diameter corresponding to the maximum of PSD calculatd by NLDFT method
from ads orption branch; t-wall thickness, calculated as t=a0-Dp.
Powder X-ray diffraction patterns of NSC1, NSC2, NSD and NSE after calcining
and reduction are shown in Fig. 3. The broad peak appearing at about 20º-30º for all
samples was attributed to amorphous silica in framework [43]. NiO diffraction peaks
at ~37º, ~43º and ~63º were observed in the XRD spectra of NSC1-C, NSC2-C,
NSD-C and NSE-C [44]. As shown in Fig. 3b, Ni diffraction peaks at ~44.5ºand ~52º
were observed in the XRD spectra of NSC1-C, NSC2-C, NSD-C and NSE-C [45].
Moreover, the diffraction peaks of NiO were still can be observed in the XRD spectra
of reduced samples, which indicated that NiO was partially converted to Ni after
reduction at 823 K. The chemical states of Ni in the NSD-C and NSD-R were also

analyzed by the Ni 2p XPS (Fig.S1). Spin-orbit doublets peaks at ~856 and ~873 eV
were observed for NSD-C and NSD-R, which were ascribed to Ni 2p3/2 and Ni 2p1/2,
respectively [46]. Peak at 852.6 eV appearing at the XPS spectra of NSD-R was
attributed to 2p3/2 of Ni0 [47]. Two satellite peaks of Ni were appeared at ~862.0 eV
and ~880.3ꢀeV for both NSD-C and NSD-R [48]. The presence of Ni2+ at the XPS
spetra of NSD-R was mainly due to the strong interactions between the Ni particles
and the support. The XPS results show that both Ni0 and Ni2+ existed on the surface of
NSD-R.
NSD-R
NiO(200)
NiO(111)
NSD-C
NSE-R
NiO(220)
NSE-C
NSC2-R
NSC2-C
NSC1-R
NSC1-C
20
30
40
50
60
70
20
30
40
50
60
70
2θ/º
2θ/º
Fig. 3. Powder X-ray diffraction patterns of nickel based Al-SBA-15 samples: (a) nickel based
Al-SBA-15 samples after calcination and (b) nickel based Al-SBA-15 samples after reduction.
SEM and TEM images of NSC1-C, NSC2-C, NSE-C and NSD-C are as shown
in Fig. 4. All the samples exhibited aggregated morphology like wheat. But for
NSD-C, part of the long rod-like particles were damaged. All the samples showed
regular long ordered pore structure. The TEM images of samples demonstrated that

particles of nickel species were existed on the surface of samples and the ordered
2D-hexagonal symmetry is observed.
Fig. 4. SEM and TEM image of calcined nickel based Al-SBA-15 samples with different organic
template removal approaches.
The FTIR spectra of NSD, NSE, NSC2 and NSC1 after calcination or reduction
are shown in Fig. 5. All samples after calcination exhibited peaks at 1630, 962, 800,
575, 466 cm-1, as well as broad bands at 1091 and 1221 cm-1. The peak appearing at
1630 cm-1 was attributed to the vibration of hydroxyl bands for adsorption water [49].
A broad band appearing at 1091 cm-1 coupling with a shoulder peak at 1221 cm-1 was
due to the asymmetric stretching vibration of Si-O-Si [49]. The reason for the
appearance of the band at about 962 cm-1 is still in dispute. It was reported that this
peak was caused by the part asymmetry of the framework due to the existence of
defects [50]. A strong shoulder peak indicated the symmetry of the framework was
decreased. The peak appearing at 962 cm-1 in NSD-C and NSD-R was significantly
stronger than that in the other three samples. The peak appearing at ~800 cm-1 was
caused by the intrinsic symmetric stretching vibration of the TO4 containing Al and Si

[35, 49, 51]. The band appearing at 575 cm-1 and 466 cm-1 was attributed to the
bending vibration of Si-O [49]. It can be seen from Fig.5 that the band appearing at
1630 cm-1 was significantly decreased after reduction of sample, which indicated that
adsorption water in samples was further removed after reduction. No other difference
was observed for these samples before and after reduction.
a
b
NSD-C
NSD-R
NSE-C
NSE-R
NSC2-C
NSC1-C
NSC2-R
NSC1-R
2000 1800 1600 1400 1200 1000 800 600 400
2000 1800 1600 1400 1200 1000 800 600 400
Wavenumber (cm-1)
Wavenumber (cm-1)
Fig. 5. FT-IR spectra of 16 % Ni based Al-SBA-15 obtained with different organic template
removal approaches: (a) represents Ni/Al-SBA-15 samples after calcination and (b) represents
Ni/Al-SBA-15 after reduction.
The 29Si MAS-NMR spectra of SC1, SC2, SE and SD are shown in Fig. 6. In the
29Si MAS-NMR spectra, three resonances at about -90, -100 and -110 nm were
obtained for all the samples, which can be ascribed to Q2, Q3 and Q4 sites,
respectively. n in Qn represents the number of the adjacent silicon atoms which are

linked with oxygen bridge. The chemical shift of Q3 ranged from -100 to -106 nm,
which was probably resulted from two structure units including Si(OSi)3(OAl) and
Si(OSi)3(OH) for Al-SBA-15 [43]. The chemical shift of Q2 at around -90 nm was
corresponded to structure units including Si(OSi)2(OH)2, Si(OSi)2(OAl)2 or
29
Si(OSi)2(OAl)(OH) [52]. The Si MAS-NMR spectra of NSC1 and NSC2 are very
similar. However, for sample SE and sample SD, the concentration of Q2 sites was
increased. Based on the Si/Al ratios obtained by XRF, it can deduced that much more
Si(OSi)3(OH) and Si(OSi)2(OAl)(OH) or Si(OSi)2(OAl)2 existed in SE. Moreover,
part of SD structure was destroyed and much more Si(OSi)3(OH) was formed.
SC1
SC2
-70
-80
-90
-100
-110
-120
-130
-140
-70
-80
-90
-100
-110
-120
-130
-140
Chemical shift (ppm)
Chemical shift (ppm)
SE
SD
-70
-80
-90
-100
-110
-120
-130
-140
-70
-80
-90
-100
-110
-120
-130
-140
Chemical shift (ppm)
Chemical shift (ppm)
Fig. 6. 29Si MAS-NMR spectra of Al-SBA-15 samples after removal of template.
3.2. Performance of eugenol hydrodeoxygenation over Ni/Al-SBA-15
The reaction results of eugenol hydrodeoxygenation over Ni/Al-SBA-15 with
different organic template removal approaches are shown in Fig. 7. The conversion of
eugenol after reaction was nearly 100 % for all the reaction. Four products, including

4-propyl-guaiacol, propylbenzene, 4-propyl-hexane and methanol, were obtained over
NSC1-R, NSC2-R, NSE-R and NSD-R, respectively. Moreover, the selectivity of
each product varied significantly with the type of catalysts. The selectivity of
4-propyl-hexane was in the order of NSE-R>NSC2-R>NSC1-R>NSD-R. The highest
selectivity of 4-propyl-hexane was obtained when using NSE-R as catalyst, which
was about 89.87 %. The lowest selectivity of 4-propyl-hexane was 3.96 %, which was
obtained when using NSD-R as HDO catalyst. The selectivity of 4-propyl-guaiacol
was in the order of NSD-R>NSC1-R>NSC2-R>NSE-R. Only few propylbenzene was
produced for all the reactions over different Ni/Al-SBA-15 catalysts. The results
showed that high hydrocarbons were obtained during hydrodeoxygenation process by
using NSE-C as catalyst. A higher hydrocarbon selectivity was obtained by the
hydrodeoxygenation over NSC2-R than that over NSC1-R. This indicated that
two-step calcination was more effective than the direct calcination process in template
removal and was much more suitable for the hydrodeoxygenation process. Through
physiochemical analysis, it can be concluded that electric heating digestion method
was not suitable for the template removal of Al-SBA-15.

Fig. 7. Eugenol hydrodeoxygenation on Ni/Al-SBA-15 with different organic template removal
approaches.
4. Conclusions
Three kind of template removing methods were introduced, including calcination,
solvent extraction and electric heating digestion. The effects of these template
removing methods on the physiochemical characterization of Ni/Al-SBA-15 and the
corresponding hydrodeoxygenation activities were investigated. In terms of specific
area, samples were in the order of NSC2-C>NSC1-C>NSD-C>NSE-C. NSC2-C had
the largest BET specific surface area, which was about 619 m2/g. NSC1-C, NSC2-C
and NSE-C had similar mesopore diameter, which was about 6.1 nm. While for
NSD-C, the mesopore diameter was increased to 6.68 nm. NSC1-C, NSC2-C and
NSE-C had similar wall thickness, which was about 12.2 nm, while NSD-C had a
decreased wall thickness, which was about 11.62 nm. Part of the ordered pore
structure in NSD-C was destroyed after removal of the organic templates by using

electric heating digestion method. The selectivity of each product varied with the type of
catalyst. Results showed that the selectivity of 4-propyl-guaiacol was in the order of
NSD-R>NSC1-R>NSC2-R>NSE-R. The results showed that high hydrocarbons were
obtained during hydrodeoxygenation process by using NSE-C as catalyst. Two-step
calcination was more effective than the direct calcination process in template removal
and was much more suitable for the hydrodeoxygenation process. Electric heating
digestion method was not suitable for the template removal of Al-SBA-15.
Acknowledgment
This work is financially supported by National Natural Science Foundation of
China Through Project (grant number 51602215), the Guangdong Provincial Key
Laboratory of New and Renewable Energy Research and Development (Y807s41001),
the Fundamental Research Funds for the Central Universities (18CX02101A), the
Independent Innovation and Entrepreneurship projects of Qingdao Institute for Ocean
Technology of Tianjin University (20190201-8) and the National Science and
Technology Major Project (grant number 2016ZX05014-004-007).
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Highlights
‹ Physicochemical properties of Al-SBA-15 were notably impacted by template
removal approaches
‹ Template removal approaches can affect the catalytic activity of Ni/Al-SBA-15
‹ Eugenol hydrodeoxygenation over Ni/Al-SBA-15 was investigated
‹ Two-step calcination method for Al-SBA-15 template removal was more
effective

Xiangping Li and Jianguang Zhang designed the research and collected the
experiment data; Xiangping Li and Han Yin wrote this paper; Xiangping Li and
Jianguang Zhang revised the paper; Guanyi Chen and Juping Liu edited the
manuscript and provided some suggestions for manuscript organization.

The named authors have no conflict of interest, financial or otherwise.