Cooperative Co0/CoII Sites Stabilized by a Perovskite Matrix Enable Selective C?O and C?C bond Hydrogenolysis of Oxygenated Arenes

Article abstract of DOI:10.1002/cssc.201900664

Strontium-substituted lanthanum cobaltite (La_0.8Sr_0.2CoO₃) matrix-stabilized Co⁰/Co^II catalytic sites were prepared, which present tunable C?O and C?C hydrogenolysis activity for the vapor-phase upgrading of oxygenated arenes. Co^II sites associated with oxygen vacancies were favored at low temperatures and performed selective C?O hydrogenolysis, in which Sr-substitution facilitated oxygen vacancy formation, leading to approximately 10 times higher reactivity compared to undoped LaCoO₃. Co⁰ sites were favored at high temperatures and performed extensive C?C bond hydrogenolysis, generating a wide range of alkanes. The lower reaction order with P (Formula presented.) (1.1±0.1) for C?C hydrogenolysis than for C?O hydrogenolysis (2.0±0.1) led to a high selectivity towards C?C hydrogenolysis at low P (Formula presented.). The Co₃O₄ surfaces featured a narrower temperature window for obtaining the respective optimal Co^II and Co⁰ pairs compared to analogous perovskite surfaces; whereas, the perovskite matrix stabilizes these pairs for selective C?O and C?C hydrogenolysis. This stabilization effect offers an additional handle to control reactivity in oxide catalysts.

Full text of DOI:10.1002/cssc.201900664

Accepted Article
Title: Cooperative Co(0)/Co(II) Sites Stabilized by a Perovskite
Matrix Enable Selective C-O and C-C bond Hydrogenolysis of
Oxygenated Arenes
Authors: Manish Shetty, Daniela Zanchet, William H Green, and Yuriy
Román-Leshkov
This manuscript has been accepted after peer review and appears as an
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the VoR from the journal website shown below when it is published
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To be cited as: ChemSusChem 10.1002/cssc.201900664
Link to VoR: http://dx.doi.org/10.1002/cssc.201900664
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Cooperative Co0/CoII Sites Stabilized by a Perovskite Matrix
Enable Selective C-O and C-C bond Hydrogenolysis of
Oxygenated Arenes
Manish Shetty[a], Daniela Zanchet[a],[b], William H. Green[a] and Yuriy Román-Leshkov*[a]
superior activity, remarkable stability and resistance to coking.[1d,
Abstract:
A
strontium (Sr)-substituted lanthanum cobaltite
10]
(La0.8Sr0.2CoO3) matrix stabilized Co0/CoII catalytic sites that featured
tunable C-O and C-C hydrogenolysis activity for the vapor-phase
upgrading of oxygenated arenes. CoII sites associated with oxygen
vacancies were favored at low temperatures and performed selective
C-O hydrogenolysis where Sr-substitution facilitated oxygen vacancy
formation and led to ~10 times higher reactivity compared to undoped
LaCoO3. Co0 sites were favored at high temperatures and performed
extensive C-C bond hydrogenolysis generating a wide range of
alkanes. The lower reaction order with PH2 (1.1 ± 0.1) for C-C
hydrogenolysis than for C-O hydrogenolysis (2.0 ± 0.1) led to high
selectivity towards C-C hydrogenolysis at low PH2. Given that Co3O4
surfaces featured a narrower temperature window for obtaining the
respective optimal CoII and Co0 pairs compared to analogous
perovskite surfaces, the perovskite matrix is implicated in stabilizing
these pairs for selective C-O and C-C hydrogenolysis. This
stabilization effect offers an additional handle to control reactivity in
oxide catalysts.
In the context of renewable transportation fuels and chemicals,
metal-metal oxide interfaces have been tailored to upgrade
1c, 11]
biomass-derived oxygenates via hydrogenolysis.[1a,
For
instance, oxygen vacancies on metal oxide can work
synergistically with metal sites to catalyze C-O bond
hydrogenolysis, through enhanced H2 activation on metal sites.[1a,
12] For ethanol steam reforming (ESR) on cobalt oxide, Co0 sites
catalyzed C-C bond cleavage, while the lattice oxide maintained
catalyst stability through the removal of dehydrogenated
fragments.[12-13] Surprisingly, despite their tremendous potential to
9, 14]
generate tunable metal-metal oxides interfaces,[1d,
perovskites have not been extensively studied as catalysts for C-
O and C-C bond cleavage in biomass-derived oxygenates.
Herein, we investigated the Sr-substituted lanthanum cobaltite
(La0.8Sr0.2CoO3) catalyst for C-O and C-C hydrogenolysis of
oxygenated arenes using coupled reactivity and characterization
measurements. Specifically, we established the cooperative role
of CoII and Co0 sites for C-O and C-C bond hydrogenolysis by
studying the kinetics of C-C and C-O bond hydrogenolysis
pathways during anisole conversion in combination with post-
reaction X-ray photoelectron spectroscopy (XPS) and in situ
powder X-ray diffraction (PXRD) coupled with temperature
programed reduction (TPR). The role of CoII sites for the C-O
hydrogenolysis was further examined by considering the effect of
Sr substitution on oxygen vacancy generation and comparing the
C-O hydrogenolysis reactivity of La0.8Sr0.2CoO3 and LaCoO3. The
reaction pathways for the hydrogenolysis products were mapped
by studying the product selectivities with varying catalyst contact
times and H2O co-feed. Kinetic data for the reaction pathways
was assembled into a kinetic model to gain mechanistic insight
into the role of Co0 and CoII sites on the hydrogenolysis products.
Overall, this study illustrates how the stabilization of interfacial
Co0 and CoII sites can be used as a handle to control C-O and C-
C hydrogenolysis activity.
Metal-metal oxide interfaces play a crucial role in governing C-
O
and C-C bond activation pathways.[1] These interfaces
modulate the activity and product selectivity by influencing the
adsorption and stabilization of intermediates, the availability of
different active sites and the reaction mechanisms through
structural and electronic effects.[2] In this respect, perovskite
oxides (ABO3), with their compositional diversity at the A and B
sites offer ample opportunities to generate these interfaces that
tune the oxygen mobility and redox properties of the catalyst.[3]
These properties have been used in numerous catalytic
applications, including volatile organic compound (VOC)
elimination,[4] soot combustion,[5] selective oxidation of alkanes,[6]
and NOx reduction.[7] Sr-substituted perovskites rivaled Pt-based
commercial catalysts for NOx reduction under simulated diesel
exhaust conditions.[7] They have also shown superior
performance and tunability in electrochemical oxygen reduction
and oxygen evolution reactions.[7-8] Most notably, recent studies
have shown that under strongly reducing conditions, some late
transition metals (e.g., Ni) in perovskites undergo exsolution,
forming surface metallic clusters that are stabilized against
agglomeration by the underlying perovskite matrix, thereby
forming controlled metal-metal oxide interfaces.[9] Such interfaces
provide oxygen vacancies for CO2 activation and metal sites for
C-C and C-H activation in the dry reforming of alkanes with
Figure 1a shows the time-on-stream conversion profiles of
anisole using La0.8Sr0.2CoO3 in the temperature range between
473 and 623 K. At 473 K (PH2 ≈ 1 bar), a 12 h transient induction
zone was observed before reaching steady state at a conversion
of 38%. At 523 K, the induction zone was significantly reduced,
reaching a maximum conversion of 72% after ~1 h on stream. At
this temperature, a conversion of 55% was measured after 18 h,
consistent with a first-order deactivation rate constant of 0.02 h-1
(Figure S2). At higher temperatures (573 and 623 K), no induction
zone was detected and the catalyst underwent a rapid initial
deactivation (0.06 and 0.36 h-1 first order constants, respectively)
achieving final conversions below 20%. The product selectivity
values were invariant after ~5 h at all temperatures (Figure S3).
[a]
[b]
Dr. M. Shetty, Prof. D. Zanchet, Prof. W.H. Green, Prof. Y Román-
Leshkov
Department of Chemical Engineering,
Massachusetts Institute of Technology
Cambridge, MA-02139 (USA)
Product selectivity was a strong function of the reaction
temperature (Figure 1b) and several reaction pathways were
identified in the temperature range between 473 and 623 K,
including C-O bond hydrogenolysis to benzene and methane, C-
C bond hydrogenolysis to form C1-C6 alkanes, hydrogenation to
form methoxycyclohexane and alkylation to form methyl anisole
and toluene. The selectivity to benzene decreased from ~75% at
473 K to ~20% at 623 K with a concomitant increase in the
selectivity to C1-C6 alkanes from ~5% at 473 K to ~70% at 623 K
E-mail: yroman@mit.edu
Prof. D. Zanchet
Institute of Chemistry, University of Campinas
Campinas, SP-13083-970 (Brazil)
Supporting information for this article is given via a link at the end of
the document
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10.1002/cssc.201900664
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(see Figure S4 for product breakdown). The remaining products
represented less than 5% at all temperatures. The increase of C-
C bond hydrogenolysis products with temperature was expected,
as the formation of metallic Co at high temperatures (vide infra)
has been shown to favor the C-C bond cleavage reactions.[15]
Interestingly, however, more than 80% of the hydrogenolysis
products corresponded to methane at 523 K (Figure S4),
suggesting strong adsorption of the reaction intermediates and
complete C-C hydrogenolysis at the active sites. Control
experiments using benzene as a feed at 523 K (Figure S5),
showed complete C-C bond hydrogenolysis to form methane with
low hydrogenation activity towards cyclohexane (~5%).
Surprisingly, cyclohexane did not react under identical conditions.
To probe the reaction pathway from anisole, the conversion and
selectivity of benzene were analyzed with varying catalyst contact
times and PH2O. The steady-state selectivity value to benzene was
independent of the catalyst contact times spanning from 0.7 to 8.3
h (Figure 2a), implying parallel pathways for C-O and C-C bond
hydrogenolysis reactions stemming from a common surface
intermediate (Scheme S1). The addition of H2O co-feed—known
to competitively adsorb on active sites of metal oxides—at 523 K
and ~9.5 h (Figure 2b) instantaneously reduced the conversion of
anisole, but did not alter the product distribution. Upon removing
H2O at 14 h, the conversion increased again, reaching ~45% at
18 h. The reduction in anisole conversion in the presence of H2O
was not due to a shift in reaction equilibrium (see Table S3). We
hypothesize that H2O blocks the sites responsible for anisole
adsorption, as also reported for steam reforming and CO
oxidation.[16] Further, H2O also inhibits the hydrogenolysis of
benzene with no appreciable changes in selectivity (Figure S5).
Taken together, we posit that the higher affinity of anisole to the
perovskite surface favors its high surface coverage and inhibits
the concerted C-C bond hydrogenolysis pathways of benzene.
Guaiacol exhibited similar reactivity trends to those of anisole
at 523 K, with selectivity values approaching nearly constant
values after ~5 h on stream (Figure S6). Both anisole and guaiacol
exhibited selective Caromatic-OCH3 bond cleavage to form benzene
and phenol, respectively (Table S2). The phenolic Caromatic-OH
bond was difficult to break in guaiacol as seen by the low
selectivity towards benzene (~1.3%) and anisole (~1.6%).
Guaiacol exhibited higher carbon accumulation rates (80% of total
surface species) compared to anisole (50 % of total surface
species) after 16 h on stream, as detected by XPS. As such,
guaiacol conversion exhibited a higher deactivation rate (rate
constant 0.07 h-1) compared to anisole (0.02 h-1), likely because
of the faster accumulation of surface carbon (Figure S7).
Figure 2. Reactivity of lanthanum strontium cobaltite (La0.8Sro.2CoO3) catalyst
including (a) Selectivity towards benzene and conversion of anisole with varying
catalyst contact times (1/WHSV) 0.7-8.3 h, 0.15-2.3 g La0.8Sro.2CoO3. (b)
Conversion of anisole and selectivity of products during anisole HDO with and
without H2O as co-feed (PH2O = 0.035 bar). Reaction conditions: PTotal = 1.013
bar (PAnisole = 0.0098 bar, balance H2 without H2O and PAnisole = 0.0098 bar, PH2O
= 0.035 bar, balance H2 with H2O).
To shed light on genesis of reactivity on La0.8Sr0.2CoO3, bulk
and surface characterization were performed on the fresh and
post-reaction catalysts (Figure 3). The PXRD pattern shows that
the fresh La0.8Sr0.2CoO3 was present in cubic structure.[17] The
post-reaction catalysts showed that the material underwent lattice
Figure 1. Reactivity of lanthanum strontium cobaltite (La0.8Sr0.2CoO3) catalyst
including (a) Conversion of anisole, and (b) Steady-state selectivity towards
benzene and light gases (split as methane contribution from anisole HDO and
other light gases) at 473–623 K, 0.3-2.0 g La0.8Sro.2CoO3. Reaction conditions:
PTotal = 1.013 bar (PAnisole = 0.0098 bar, balance H2).
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10.1002/cssc.201900664
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catalyst stability. In order to reinforce the role of CoII sites towards
catalyst stability, anisole conversion was studied on cobalt oxide
(Co3O4) catalyst under similar reaction conditions. At 473 K, the
induction zone of 3h can be associated with the conversion of
Co3O4 to CoO (Figures S14 and S16). At 523 and 573 K, the
catalyst exhibited a higher deactivation rate (first-order constant
0.08 and 0.10 h-1, respectively in Figure S15) than La0.8Sr0.2CoO3,
which is likely associated with the formation of Co metal (Figure
S16). At 623 K, Co3O4 completely converted into Co metal and
lost all catalytic activity (Figures S14 and S16) in stark contrast to
La0.8Sr0.2CoO3, which still exhibited metal-vacancy pairs at 623 K.
The role of CoII sites (oxygen vacancies) towards C-O
hydrogenolysis, reactivity was further examined by comparing the
rates for anisole conversion to benzene on La0.8Sr0.2CoO3 and
LaCoO3 (Table S5) at 523 K. Mefford et al. reported a ~0.5 eV
decrease in oxygen vacancy formation energy with Sr substitution
from LaCoO3 to La0.75Sr0.25CoO3.[8] For C-O hydrogenolysis on
distortion, as indicated by the shift of the peaks at 2Θ = 23.50 and
480 to lower 2Θ values and splitting of the peaks at 33.50, 410 and
590. These peak splittings have been attributed to octahedral
tilting due to oxygen vacancy formation[18] and lattice
expansion.[19] Interestingly, after exposure to air at room
temperature, the PXRD pattern resembled the original pattern
(Figure S9) suggesting that the lattice distortion under reaction
condition is mostly reversed under oxidizing conditions.[20] Metallic
Co was detected in the catalyst used at 623 K. H2-TPR (Figure
S8) showed that the reduction threshold of Co(III,IV) in
La0.8Sr0.2CoO3 was ~553 K, in agreement with the lattice distortion
detected by in situ PXRD (Figure S10).
XPS was used to probe the changes in the catalyst surface
composition post reaction. The Co 2p3/2 spectra (Figure 3b)
shows that the fresh catalyst mainly featured Co(III,IV) species,[21]
while after reaction, broader peaks appeared along with the
satellite peak at ~785 eV (characteristic of octahedral CoII
moieties). Thus, the Co species in the perovskite undergo partial
reduction during reaction, consistent with the oxygen vacancy
formation. At 623 K, the presence of Co0 species at ~778 eV was
detected, corresponding to ~8% Co0 at the surface (Figure S11),
in agreement with post-reaction PXRD. The O1s, La 3d5/2 and Sr
3d profiles did not exhibit any changes post-reaction (Figure S11).
oxides following a reverse Mars-van-Krevelen mechanism, this
8]
effect should lead to
a
higher reactivity.[1a,
Indeed,
La0.8Sr0.2CoO3 exhibited both specific and areal reaction rates an
order of magnitude larger than unsubstituted LaCoO3. These
results strongly suggest the involvement of CoII sites for C-O bond
hydrogenolysis, although other parameters such as surface
composition and crystallinity can also contribute to the superior
performance.[22]
The hydrogenation relative to hydrogenolysis of benzene on
metals has been suggested to be related to its adsorption
modes.[23] While hydrogenation may proceed through a weakly
bound -bonded intermediate, the hydrogenolysis is promoted by
a strong chemisorption involving multiple metal-carbon bonds.[23b]
On a perovskite surface, we propose that an oxygenate adsorbs
on an oxygen vacancy (Scheme 1). The level of hydrogenolysis
likely depends on the prevalence of the Co0 sites and the resulting
Co-CAromatic bonds. With an increase in temperature, larger
concentration of surface Co0 sites are formed that promote C-C
24]
hydrogenolysis reactivity.[21,
Notably, the perovskite matrix
appears to maximize such metal-vacancy pairs over a wider
temperature range than what could be obtained with a regular
monometallic oxide, as shown earlier.
Figure 3. Post-reaction characterization of La0.8Sr0.2CoO3 catalyst (a) PXRD
pattern, and (b) XP spectra. Measurements performed at room temperature.
The dashed lines in (a) corresponds to the main perovskite peaks (ICDD 04-
018-5367) whereas the * indicates the (111) peak of metallic fcc Co (ICSD
622438). In (b), the dashed lines indicates the regions associated the different
Co species.
Scheme 1. Proposed pathways for anisole conversion on La0.8Sr0.2CoO3
catalyst surface. Anisole adsorbs on the catalyst surface on an oxygen vacancy
(represented by empty box) and the aromatic carbon atoms are associated with
an ensemble of metallic Co0 (represented as Co(0)) moieties.
In order to probe the reaction mechanism for anisole
conversion, we examined the reaction kinetics of C-O and C-C
bond hydrogenolysis from anisole at 523 K. As shown in Figure
The concomitant increase in the formation of Co0 sites with the
increase in deactivation rate of the catalyst, with reaction
temperature (Figure S2) suggests that CoII sites are crucial for the
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4, both C-O and C-C hydrogenolysis rates exhibit zero order with
varying PAnisole suggesting saturation of anisole intermediates on
oxygen vacancies. Specifically with respect to PH2, the formation
of C-O and C-C hydrogenolysis products show reaction order of
2.0 ± 0.1 and 1.1 ± 0.1, respectively. Due to the lower reaction
order for C-C hydrogenolysis than C-O, a deleterious increased
selectivity to C-C hydrogenolysis products against benzene
(Figure S18) was observed with decreasing PH2 (~8% to ~57% as
PH2 was decreased from 2.0 to 0.1 bar).
substituting other transition metals (e.g., Fe and Ni) in place of Co
in LaCoO3, our results clearly demonstrate new avenues for
tuning the reactivity of perovskites and for developing highly
active and selective catalysts under mild conditions.
Acknowledgements
This work was supported by BP and the National Science Foundation,
CBET Award No 1454299. The authors would like to thank Karthick
Murugappan and Shiran Zhang for help with XPS data, and Charlie
Settens at CMSE, MIT for help with in situ PXRD measurements. D.Z.
acknowledges funding by the Sao Paulo Research Foundation (FAPESP
2015/23900-2) and the National Council of Technological and Scientific
Development (CNPQ 309373/2014-0).
The observed reaction orders are consistent with a mechanistic
model of anisole adsorption and its conversion to benzene on an
oxygen vacancy (CoII sites). With the participation of Co0 sites in
close proximity to CoII sites, the adsorbed anisole can also
undergo a sequence of hydrogenation and dehydrogenation
steps to form H-deficient intermediates. The proposed
mechanism (detailed in Supplementary Note 1) shows that the H
content of equilibrated surface species leading to C-C
hydrogenolysis requires H addition to achieve appreciable
Conflict of Interest
coverage of active surface species that undergo C-C bond
[25]
cleavage, consistent with the positive reaction order with PH2
.
The authors declare no conflict of interest.
PAnisole /bar
0.008
0.010
0.012
Keywords: biomass conversion• heterogeneous catalysis•
metal-metal oxide interfaces• perovskite phases• reaction
mechanisms
10
7
102
101
C-O bond
2.0 ± 0.1
References
C-C bond 4
1.1 ± 0.1
100
[1]
a) A. V. Mironenko, D. G. Vlachos, J. Am. Chem. Soc. 2016, 138,
8104-8113; b) S. Kattel, P. Liu, J. G. G. Chen, J. Am. Chem. Soc.
2017, 139, 9739-9754; c) X. Xiao, H. Bergstrom, R. Saenger, B.
Johnson, R. Sun, A. Peterson, Catal. Sci. Technol. 2018, 8, 1819-
1827; d) B. H. Zhao, B. H. Yan, S. Y. Yao, Z. H. Xie, Q. Y. Wu,
R. Ran, D. Weng, C. Zhang, J. G. G. Chen, J Catal 2018, 358,
168-178; e) E. M. Anderson, M. L. Stone, M. J. Hulsey, G. T.
Beckham, Y. Roman-Leshkov, ACS Sustainable Chem Eng 2018,
6, 7951-7959; f) K. Murugappan, E. M. Anderson, D. Teschner,
T. E. Jones, K. Skorupska, Y. Roman-Leshkov, Nat Catal 2018,
1, 960-967.
10-1
10-2
10-3
C-O bond
C-C bond
1
0.1
1
PH2 /bar
[2]
[3]
[4]
A. R. Puigdollers, P. Schlexer, S. Tosoni, G. Pacchioni, ACS
Catal. 2017, 7, 6493-6513.
S. Royer, D. Duprez, F. Can, X. Courtois, C. Batiot-Dupeyrat, S.
Laassiri, H. Alamdari, Chem. Rev. 2014, 114, 10292-10368.
N. Russo, D. Fino, G. Saracco, V. Specchia, J Catal 2005, 229,
459-469.
Figure 4. Reaction rate of C-O and C-C hydrogenolysis products from anisole
with varying PAnisole (0.008-0.012 bar) and PH2 (0.1-5 bar) on lanthanum
strontium cobaltite (La0.8Sro.2CoO3) catalyst (0.1-2.35 g) at 523 K. Reaction
conditions: PTotal = 1.013 bar at PH2 ≤ 1 bar, else PTotal ≈ PH2. N2 was used as a
balance gas when PH2 < 1.0 bar.
Previous reports have studied the hydrogenation and
hydrogenolysis of C2-C5 olefins and alkanes on LaCoO3.[21, 24b, 26]
With the aid of mechanistic analysis and tracer studies with D2, it
was deduced that the hydrogenolysis of olefins to form methane
occurred through H deficient active surface species consistent
with our hypothesis.[26b] In contrast to these reports, we do not
observe any hydrogenolysis activity of alkanes. The stabilization
of the bulk oxide lattice appeared to favor catalyst stability with
the partial reduction of Co favoring hydrogenolysis and
hydrogenation activity.[21, 27] Due to the catalyst deactivation with
over-reduction to Co metal, Ichimura et al. attributed the
hydrogenolysis activity to Co(III) moieties,[24b] while Ulla et al.
attributed both the hydrogenation and hydrogenolysis activity to
the presence of Co(0) moieties dispersed on the perovskite
matrix[27b] consistent with our mechanistic model for C-C bond
hydrogenolysis.
[5]
[6]
J. R. Mawdsley, T. R. Krause, Appl. Catal. A 2008, 334, 311-320.
C. H. Kim, G. S. Qi, K. Dahlberg, W. Li, Science 2010, 327,
1624-1627.
J. Suntivich, H. A. Gasteiger, N. Yabuuchi, H. Nakanishi, J. B.
Goodenough, Y. Shao-Horn, Nat Chem 2011, 3, 647-647.
J. T. Mefford, X. Rong, A. M. Abakumov, W. G. Hardin, S. Dai,
A. M. Kolpak, K. P. Johnston, K. J. Stevenson, Nat Commun
2016, 7, 11053.
B. H. Zhao, B. H. Yan, Z. Jiang, S. Y. Yao, Z. Y. Liu, Q. Y. Wu,
R. Ran, S. D. Senanayake, D. Weng, J. G. G. Chen, Chem.
Commun. 2018, 54, 7354-7357.
S. Singh, D. Zubenko, B. A. Rosen, ACS Catal. 2016, 6, 4199-
4205.
a) N. M. Briggs, L. Barrett, E. C. Wegener, L. V. Herrera, L. A.
Gomez, J. T. Miller, S. P. Crossley, Nat. Commun. 2018, 9, 3827;
b) E. M. Anderson, M. L. Stone, R. Katahira, M. Reed, G. T.
Beckham, Y. Román-Leshkov, Joule 2017, 1, 613-622; c) M. L.
Stone, E. M. Anderson, K. M. Meek, M. Reed, R. Katahira, F.
Chen, R. A. Dixon, G. T. Beckham, Y. Roman-Leshkoy, Acs
Sustainable Chem Eng 2018, 6, 11211-11218; d) M. Shetty, K.
Murugappan, T. Prasomsri, W. H. Green, Y. Roman-Leshkov, J.
Catal. 2015, 331, 86-97; e) M. Shetty, K. Murugappan, W.H.
Green, Y. Roman-Leshkov, ACS Sustainable Chem Eng 2017, 5,
5293-5301.
[7]
[8]
[9]
[10]
[11]
Overall, our results demonstrate the tunability of the C-O and
C-C bond hydrogenolysis on perovskites with varying
temperature and PH2. While selective C-C hydrogenolysis was
favored at high temperature and low PH2
, selective C-O
hydrogenolysis can be achieved at low temperature and high PH2
.
We also demonstrated the positive impact of Sr substitution on
the C-O hydrogenolysis rates. Together with the possibility of
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[12]
[13]
[14]
[15]
D. Zanchet, J. B. O. Santos, S. Damyanova, J. M. R. Gallo, J. M.
C. Bueno, Acs Catal 2015, 5, 3841-3863.
C. Huck-Iriart, L. Soler, A. Casanovas, C. Marini, J. Prat, J.
Llorca, C. Escudero, Acs Catal 2018, 8, 9625-9636.
M. Y. Chen, C. B. Chen, B. Zada, Y. Fu, Green Chem 2016, 18,
3858-3866.
T. R. Reina, E. Papadopoulou, S. Palma, S. Ivanova, M. A.
Centeno, T. Ioannides, J. A. Odriozola, Appl. Catal. B 2014, 150,
554-563.
[16]
[17]
[18]
G. A. Martin, J Catal 1979, 60, 345-355.
M. Crespin, W. K. Hall, J Catal 1981, 69, 359-370.
S. Qin, A. I. Becerro, F. Seifert, J. Gottsmann, J. Z. Jiang, J Mater
Chem 2000, 10, 2401-2401.
[19]
A. Y. Zuev, A. I. Vylkov, A. N. Petrov, D. S. Tsvetkov, Solid
State Ionics 2008, 179, 1876-1879.
[20]
[21]
J. H. Kim, Appl Surf Sci 2011, 258, 350-355.
M. A. Ulla, E. A. Lombardo, Bull. Chem. Soc. Jpn. 1982, 55,
2311-2312.
[22]
X. Cheng, E. Fabbri, M. Nachtegaal, I. E. Castelli, M. El Kazzi,
R. Haumont, N. Marzari, T. J. Schmidt, Chem Mater 2015, 27,
7662-7672.
[23]
[24]
a) P. H. Desai, J. T. Richardson, J Catal 1986, 98, 392-400; b) H.
Kubicka, J Catal 1968, 12, 223-237.
a) J. Volter, M. Hermann, K. Heise, J Catal 1968, 12, 307-313;
b) K. Ichimura, Y. Inoue, I. Yasumori, Bull. Chem. Soc. Jpn.
1982, 55, 2313-2314; c) J. H. Sinfelt, Catal Lett 1991, 9, 159-172.
D. W. Flaherty, E. Iglesia, J. Am. Chem. Soc. 2013, 135, 18586-
18599.
a) K. Ichimura, Y. Inoue, I. Yasumori, Bull. Chem. Soc. Jpn.
1980, 53, 3044-3049; b) K. Ichimura, Y. Inoue, I. Yasumori, Bull.
Chem. Soc. Jpn. 1981, 54, 1787-1792.
[25]
[26]
[27]
a) J. O. Petunchi, J. L. Nicastro, E. A. Lombardo, J. Chem. Soc.
Chem. Commun. 1980, 467-468; b) J. O. Petunchi, M. A. Ulla, J.
A. Marcos, E. A. Lombardo, J Catal 1981, 70, 356-363.
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10.1002/cssc.201900664
ChemSusChem
COMMUNICATION
COMMUNICATION
Strontium-substituted lanthanum
cobaltite (La0.8Sr0.2CoO3) stabilizes
Co0/CoII pairs to enable tunable C-
O and C-C bond hydrogenolysis of
lignin-derived oxygenated arenes.
Manish Shetty, Daniela Zanchet,
William H. Green and Yuriy Román-
Leshkov
Page No. – Page No.
Cooperative Co0/CoII sites stabilized
by a perovskite matrix enable
selective C-O and C-C bond
hydrogenolysis of oxygenated
arenes
This article is protected by copyright. All rights reserved.