CASCATBEL Newsletter
www.cascatbel.eu
A P RI L
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CONTENT:
CASCATBEL Project 1
Governing Board
Meeting in Milan
(Italy)
1
A DFT study of Ni
clusters ...
2
Hydrothermally Stable, Conformal….. 3
Adsorption of Ruthenium Atoms….
4
Understanding the
Structure of …
5
Mechanism of the
Cyclo-Oligomerisation of C2H2….
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Hierarchical Mesopourous……..
7
CASCATBEL PROJECT
ASCATBEL is an European Commission’s Seventh Framework programme Project. It started in November 2013 and it is running for 4 years. The project brings together 17 partners from 10 different European countries. CASCATBEL aims to design, op mize and scale‐up a novel mul ‐step process for the produc on of second‐
genera on liquid biofuels from lignocellulosic biomass in a cost‐efficient way through the use of next‐genera on high surface area tailored nano‐catalysts. The strategy propo‐
sed in CASCATBEL will lead to the prepara on of advanced biofuels having composi on and proper es very similar to petroleum‐derived fuels. This is a very relevant advantage regarding the commercial implementa on of this technology, as it would not require any significant changes in the already exis ng infrastructures and engines. Governing Board Meeting in Milan (Italy)
Assessing Biomass
catalytic….
8
Events
9
10
Partners
C
2 0 16
On 27-28th of February
2014, 1st CASCATBEL
th Governing Board mee ng of CASCATBEL project Governing BoardThe 5
meeting
took place in Hamburg,
took place on 16th February in Milan, Italy. Germany. The meeting
was organized byThe mee
TUHH ng was organized by ENI S.p.A. with the par‐
cipa
on of 27 representa ves out of the 17 partners. and representatives
of the
17 partners of the consortium participated in it.
This mee ng aimed to review the project status of the The following main issues
were discussed: project and the next ac vi es, deliverables and mile‐
stones. Current status
of
the project and manage ment issues, including
The next CASCATBEL Governing Board mee ng will deliverables, publications
take place on 16th and 17th May in Thessaloniki, Greece. and events organization.
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A DFT study of Ni clusters deposition on titania and zirconia
(101) surfaces
Sergio Tosoni *, Hsin‐Yi Tiffany Chen, Gianfranco Pacchioni. CASCATBEL PUBLICATIONS http://dx.doi.org/10.1016/j.susc.2015.04.004
Surface Science 646 (2016) 230–238
D
ensity func onal calcula ons are employed to simulate the deposi on of an isolated Ni atomand a Ni10 par cle on the stoichiometric and reduced anatase TiO2 (101) and tetragonal ZrO2 (101) surfaces. The main purpose of this work is to study the modifica on of the electronic structure of the oxide induced by the metal, aiming at the understanding of the physical proper es of new catalysts for biomass conversion. When the adsorp on of a Ni atom takes place on stoichiometric surfaces, no major charge transfer is observed. On reduced tania, and more pronouncedly on reduced zirconia, the Ni atomis nega vely charged, provided that the vacancy is in direct contact with the adsorbed metal atom. For Ni10, on tania the bonding is dominated by the hybridiza on of the metal and the oxide states but we did not find evidence for a direct reduc‐
on of the oxide via forma on of Ti3+ states. For Ni10 on zirconia, the metal par cle is posi vely charged on the stoichiometric surface and nega vely charged on the reduced one but, again, the‐
re is no indica on of a direct reduc on of the oxide. Finally, the reverse oxygen spillover is consi‐
dered as a possible route to reduce the oxide support. The result is that Ni10 promotes oxygen spi‐
llover on tania almost spontaneously, while on zirconia this process is thermodynamically unfa‐
vourable. Keywords: Oxide surfaces, heterogeneous catalysis, supported metal nanopar cles, density func onal calcula ons, oxygen spillover.
CASCATBEL
NEWSLETTER
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Hydrothermally Stable, Conformal, Sulfated Zirconia Monolayer
Catalysts for Glucose Conversion to 5‑HMF
Amin Osatiashtiani,† Adam F. Lee,† Marta Granollers,‡ D. Robert Brown,‡ Luca Olivi, ‡Gabriel Mora‐
les,§ Juan A. Melero,§ and Karen Wilson*,†. CASCATBEL PUBLICATIONS http://dx.doi.org/10.1021/acscatal.5b00965
ACS Catal. 2015, 5, 4345−4352
T
he gra ing and sulfa on of zirconia conformalmonolayers on SBA‐15 to create meso‐
porous catalysts of tunable solid acid/base character is reported. Conformal zirconia and sulfated zirconia (SZ) materials exhibit both Brönsted and Lewis acidity, with the Brönsted/Lewis acid ra o increasing with film thickness and sulfate content. Gra ed zirconia films also exhibit amphoteric character, whose Brönsted/Lewis acid site ra o increases with sulfate loading at the ex‐
pense of base sites. Bilayer ZrO2/SBA‐15 affords an ordered mesoporous material with a high acid site loading upon sulfa on and excellent hydrothermal stability. Cataly c performance of SZ/SBA‐15 was explored in the aqueous phase conversion of glucose to 5‐HMF, delivering a 3‐fold enhance‐
ment in 5‐HMF produc vity over nonporous SZ counterparts. The coexistence of accessible solid ba‐
sic/Lewis acid and Brönsted acid sites in gra ed SZ/SBA‐15 promotes the respec ve isomeriza on of glucose to fructose and dehydra on of reac vely formed fructose to the desired 5‐HMF pla orm chemical. Keywords: SBA-15, sulfated zirconia, solid acid, 5-HMF, hydrothermal stability, solid base. CASCATBEL
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Adsorption of Ruthenium Atoms and Clusters on Anatase TiO2 and
Tetragonal ZrO2(101) Surfaces: A Comparative DFT Study
Hsin‐Yi Tiffany Chen, Sergio Tosoni, and Gianfranco Pacchioni* CASCATBEL PUBLICATIONS http://dx.doi.org/10.1021/jp510468f
J. Phys. Chem. C 2015, 119, 10856−10868
T
he electronic proper es of a single Ru atom and a Ru10 cluster adsorbed on stoichio‐
metric and reduced anatase, a‐TiO2(101), and tetragonal zirconia, t‐ZrO2(101), surfaces have been determined with density func onal theory calcula ons with Hubbard correc ons (DFT+U). The main purpose of the work is to be er understand the role of dispersed metals on the surface of tania and zirconia catalysts in conversion of biomass to biofuels. On the stoichiometric surfaces, the metal adsorp on does not imply major charge transfers. The situa on is different on the redu‐
ced surfaces where electron transfer occurs from the oxide to the metal; this effect is more pro‐
nounced on zirconia than on tania. On both surfaces, the presence of the Ru nanopar cle favors the removal of O from the surface layers. This can result in the occurrence of O reverse spillover, with displacement of an O atom from a la ce posi on of the stoichiometric surfaces to a specific adsorp on site of Ru10. This process is thermodynamically accessible for both TiO2 and ZrO2 surfa‐
ces showing that the metal deposi on can result in an easier reduc on of the oxide support due to this effect more than to a direct electron transfer from the metal. CASCATBEL
NEWSLETTER
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Understanding the Structure of Cationic Sites in Alkali Metal-Grafted
USY Zeolites
Tobias C. Keller,†,§ Miroslav Položij,‡,§ Begoña Puértolas,† Ho Viet Thang,‡ Petr Nachtigall,*,‡ and Javier Pérez‐Ramírez*,† CASCATBEL PUBLICATIONS http://dx.doi.org/10.1021/acs.jpcc.5b12413
J. Phys. Chem. C 2016, 120, 4954−4960
T
his contribu on describes the structure of ca onic sites in alkali metalgra ed high‐
silica USY zeolites, a novel class of zeolite base catalysts, through the combina on of computa onal studies and experimental evidence. Based on density func onal theory calcula ons, we inves gate the geometry various defects that coordinate sodium or potassium, and their interac‐
on with adsorbed CO. The predicted COstretching frequencies are verified experimentally by infra‐
red spectroscopy, which indicates the existence of a distribu on of different site geometries rather than a single site type. The corresponding bands lie in the range of 2180−2160 and 2170−2145 cm−1 for Na+ and K+ ca ons, respec vely. While CO primarily interacts with the gra ed metal ca on (effect from the bo om), the CO stretching frequency is strongly modulated by neighboring silanol groups (effect from the top). Based on a good agreement of experimental and theore cal results, the deprotona on of silanol groups to silanolates followed by an ion exchange appears to be a rea‐
lis c mechanism for alkali metal incorpora on in silica‐rich USY zeolites. The developed insights on the ca on site structure represent an important step to understand the cataly c performance of these basic zeolites in aldol‐type reac ons, and pave the way for future studies inves ga ng transi‐
on states to resolve their role in catalysis. CASCATBEL
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Mechanism of the Cyclo-Oligomerisation of C2H2 on
Anatase TiO2 (101) and (001) Surfaces and Their
Reduction: An Electron Paramagnetic Resonance and
Density Functional Theory Study
Hsin‐Yi Tiffany Chen,[a] Stefano Livraghi,[b] Elio Giamello,[b] and Gianfranco Pacchioni*[a] CASCATBEL PUBLICATIONS DOI : 10.1002/cplu.201500383
ChemPlusChem 2016, 81, 64 – 72
D
ehydroxylated, hydroxylated and hydrated anatase TiO2 samples have been exposed to acetylene at room temperature. The interac on leads to the forma on of poly‐
cyclic aroma c hydrocarbons (PAHs) and is accompanied by the appearance of Ti3+ ions, as shown by electron paramagne c resonance (EPR) spectra. Fully or partly dehydroxylated samples show higher reac vity, whereas the hydrated samples are chemically inert. The experimental results point towards a crucial role of the more reac ve (001) facets of anatase nanopar cles. Density func onal theory calcula ons show that acetylene physisorbs on the anatase (101) surface without ac va on of the C¢H bond. The reduced (101) surface (O vacancies) leads to acetylene ac va on but not to dissocia ve adsorp on. In contrast, the dehydroxylated (001) anatase surfa‐
ce is very ac ve and leads to the spontaneous spli ng of the C¢H bond with forma on of Ti‐C2H and OH groups. This is followed by subsequent addi ons of C2H2 molecules with forma on of PAHs. During the dissocia on of C2H2, radical species do not form and electrons are not transfe‐
rred to the surface because direct Ti‐C covalent bonds form on the surface. However, the ring clo‐
sure in the forma on of the aroma c compounds leaves behind hydrogen atoms that donate their valence electrons to the oxide. This results in the appearance of EPR‐ac ve Ti3+ centres. CASCATBEL
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Hierarchical Mesoporous Pd/ZSM-5 for the Selective Catalytic
Hydrodeoxygenation of m-cresolto Methylcyclohexane
James A. Hunns,a Marta Arroyo,b Adam F. Lee,a José M. Escola,b David Serrano*bc and Karen Wilson*a CASCATBEL PUBLICATIONS http:// DOI: 10.1039/c5cy02072g
Catal. Sci. Technol., 2016, 6, 2560–2564
M
esopore incorpora on into ZSM‐5 enhances the dispersion of Pd nanopar cles throughout the hierarchical framework, significantly accelera ng m-cresol conver‐
sion rela ve to a conven onal microporous ZSM‐5, and drama cally increasing selec vity towards the desired methylcyclohexane deoxygenated product. Increasing the acid site density further pro‐
motes m-cresol conversion and methylcyclohexane selec vity through efficient dehydra on of the intermediate methylcyclohexanol. Advances in the thermochemical processing of lignocellulosic bio‐
mass offer scalable routes to the produc on of sustainable liquid transporta on biofuels from diver‐
se waste‐derived feedstocks.1 Pyroly c thermal decomposi on of biomass delivers a broad product distribu on, which varies with feedstock, reac on temperature and residence me.2 Intermediate pyrolysis typically u lises low temperatures between 300–500 °C and long residence mes which favour charcoal forma on, whereas fast pyrolysis uses moderate temperatures of 450–550 °C and short vapour residence mes <6 s to op mise liquid produc on. Higher temperatures and longer residence mes favour gasifica on for direct power genera on and upgrading of (purified) syngas via Fischer Tropsch and methanol synthesis. Of these routes, fast pyrolysis is the most promising for the direct conversion of agricultural waste and short rota on crops to bio‐oils which retain up to 70% of the energy content of the raw biomass. Unfortunately, such fast pyrolysis bio‐oils possess undesirable physicochemical proper es including high oxygen contents of around 40 wt%, low pH, high viscosity and poor thermal stability, and rela vely poor hea ng values of 16–19 MJ kg−1, which hinders their use as drop‐in petroleum replacement fuels in conven onal combus on engines. Scheme 1 Proposed reac on pathways for m‐cresol HDO over Pd/ ZSM‐5 catalysts. CASCATBEL
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Assessing Biomass Catalytic Pyrolysis in Terms of Deoxygenation
Pathways and Energy Yields for the Efficient Production of
Advanced Biofuels
H. Hernandoa, S. Jimenez‐Sancheza, J. Fermosoa, P. Pizarroa,b, J. M. Coronadoa and D. P. Serranoa,b* CASCATBEL PUBLICATIONS DOI: 10.1039/C6CY00522E
Catal. Sci. Technol., 2016,6, 2829-2843
T
he present work focuses on the pathways through which cataly c pyrolysis of bio‐
mass into bio‐oil proceeds and the effect of the opera on condi ons on parameters like bio‐oil oxygen composi on and mass yield, but also addi onal indicators, such as the distribu‐
on of both the oxygen and the chemical energy contained in the ini al biomass among the diffe‐
rent products. Acid washed wheat straw was used as biomass feedstock. The pyrolysis tests were performed in a labscale downdra fixed‐bed reactor working at atmospheric pressure, employing a nanocrystalline H‐ZSM‐5 zeolite as catalyst. A systema c study was carried out consis ng on de‐
coupling both the thermal and cataly c reac ons in order to evaluate the influence of three key variables: temperature of the thermal zone; temperature of the subsequent cataly c step and ca‐
talyst/biomass ra o. Increasing the pyrolysis temperature in the thermal zone resulted in more bio‐oil* (bio‐oil in water‐free basis) produc on to the detriment of char and water frac ons. In contrast, a significant reduc on in bio‐oil* frac on, due to decarbonyla on and decarboxyla on, occurred when increasing the cataly c bed temperature from 400 up to 500°C. A similar effect was observed by varying the catalyst/biomass ra o since it increased the produc on of CO, CO2, light olefins and coke at expenses of a decline of the bio‐oil* yield. Nevertheless, this bio‐oil con‐
tains oxygen amounts as low as 10 wt%, while retaining about 38% of the energy yield. Char, coke and gaseous hydrocarbons contain a great part of the biomass chemical energy, hence their for‐
ma on should be suppressed or minimized to further improve the bio‐oil* energy yield. At high catalyst/biomass ra os the bio‐oil becomes rich in aroma c compounds, both oxygenated and hydrocarbons, while the content of sugars, furans, carboxylic acids, and other oxygenated pro‐
ducts is strongly reduced. CASCATBEL
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ENMIX/FASTCARD/CASCATBEL/BIOGO Workshop January 20 ‐ 21, 2016, Stu gart (Germany) In the Joint Workshop of ENMIX, FASTCARD, CASCATBEL and BIOGO projects the speakers presented their projects and lectures about the obtained research results. Along the event the partners discussed from different points of view about their projects, its development, possible synergies and future col‐
labora ons. www.cascatbel.eu
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