Temperature-Induced Structure Reconstruction to Prepare a Thermally Stable Single-Atom Platinum Catalyst

Article abstract of DOI:10.1002/anie.202004929

Single-atom noble metals on a catalyst support tend to migrate and agglomerate into nanoparticles owing to high surface free energy at elevated temperatures. Temperature-induced structure reconstruction of a support can firmly anchor single-atom Pt species to adapt to a high-temperature environment. We used Mn₃O₄ as a restructurable support to load single-atom Pt and further turned into single-atom Pt-on-Mn₂O₃ catalyst via high-temperature treatment, which is extremely stable under calcination conditions of 800 °C for 5 days in humid air. High-valence Pt⁴⁺ with more covalent bonds on Mn₂O₃ are essential for anchoring isolated Pt atoms by strong interaction. An optimized catalyst formed by moderate H₂O₂ etching exhibits the best performance and excellent thermal stability of single-atom Pt in high-temperature CH₄ oxidation on account of more exposed Pt atoms and strong Pt-Mn₂O₃ interaction.

Full text of DOI:10.1002/anie.202004929

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: Temperature-induced structure reconstruction to prepare
thermally stable single-atom Pt catalyst
Authors: Dongxu Yan, Jing Chen, and Hong-Peng Jia
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.202004929
Link to VoR: https://doi.org/10.1002/anie.202004929

10.1002/anie.202004929
Angewandte Chemie International Edition
Temperature-induced structure reconstruction to prepare
thermally stable single-atom Pt catalyst
Dongxu Yan,[a],[b] Jing Chen,[b],[c],[d] Hongpeng Jia*[a],[b]
[a]
CAS Center for Excellence in Regional Atmospheric Environment, and Key
Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese
Academy of Sciences, Xiamen, 361021, China.
[b] University of Chinese Academy of Sciences, Beijing, 100049, China.
[c] Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,
Fuzhou, Fujian 350002, China.
[d]
Xiamen Institute of Rare-earth Materials, Haixi Institutes, Chinese Academy of
Sciences, Xiamen, Fujian 361021, China.
*Corresponding author.
Email: hpjia@iue.ac.cn (H.J.)
1
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Abstract: Single-atom noble metal on catalyst support tend to migrate and agglomerate
into nanoparticles due to high surface free energy at elevated temperatures.
Temperature-induced structure reconstruction of support can firmly anchor single-atom
Pt species to adapt high-temperature environment. We used Mn3O4 as a restructurable
support to load single-atom Pt and further turned into single-atom Pt-on-Mn2O3 catalyst
via high-temperature treatment, which is extremely stable under calcination conditions
of 800oC for 5 days in humid air. Experiments reveal that high valence Pt4+ with more
covalent bonds on Mn2O3 are essential for anchoring isolated Pt atoms by strong
interaction. Optimized catalyst by moderate H2O2 etching exhibits the best catalytic
performance and the excellent thermal stability of single-atom Pt in high-temperature
CH4 oxidation on account of more exposed Pt atoms and strong Pt-Mn2O3 interaction.
2
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Oxide-supported noble-metal catalysts have received tremendous attention due to their
extensive utilization in many fields such as chemical synthesis, energy conversion and
environmental purification. Although the introduction of noble metal plays a critical
role in enhancing reactivity and changing selectivity, the relatively low natural
abundance and expensive price of noble metal hinder the large-scale application of such
catalysts. The appearance and development of single-atom catalysts (SACs) provides a
better alternative strategy because of its maximized noble metal atom-utilization
efficiency.[1] Unique metal coordination environment makes SACs to show more
remarkable catalytic behavior in specific reaction than normal noble-metal catalysts.[2]
To obtain SACs, several innovative synthetic strategies have been developed including
thermal emitting, ball milling, atomic layer deposition, and wet-chemistry approaches.[3]
Nevertheless, single-atom noble metals tend to aggregate into nanoclusters (NCs) or
nanoparticles (NPs) at high-temperature reactions, resulting in the noteworthy
reduction of catalytic activity.[4] Hence, stabilizing noble metals on catalyst support in
single-atom status remains a formidable challenge.
At high-temperature, the difference in free energy and density of adatoms drives
the migration of single atoms to NPs, which is the main reason for the sintering of SACs
and called Ostwald Ripening.[5] To resist sintering of SACs, noble metal atoms trapping
on defective metal oxides (such as CeO2) was proposed, where atoms loaded on the
defects have relatively low free energy and maintain the stability of noble metal single
atom at high-temperature.[1b, 6] However, the density of defects and surface area of
support have great effect on concentration of single atoms, so that the preparation of
thermally-stable SACs with high-density noble metal single atoms is more difficult.
Recently, Wei et al. and Lang et al. reported high-density and thermally stable SACs
synthesized by the reversed sintering process, in which noble metal particles can
3
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
convert into single atoms at high-temperature based on the thermal behavior of
supported noble metal particles.[7] Although it is achieved to obtain SACs, the
conversion process of particles to atoms at high-temperature is commonly
uncontrollable. Therefore, we think about the possibility to determine thermally-stable
SACs through using controllable thermal behavior of support. Additionally, it is more
necessary to validate the stability of single-atom dispersion of SACs for a long time at
high temperature in humid air or reaction atmosphere.
Herein, we report a new synthetic strategy of superior thermally-stable platinum
SACs through structure reconstruction of MnOx support at elevated temperature. We
utilized Mn3O4 as a preloading support for single-atom Pt that could firmly anchor Pt
atoms on support in the following phase transition to Mn2O3 induced by high-
temperature treatment. We observed that confined Pt atoms on Mn2O3 converted into
high-valent Pt4+ species with strong interaction,[7b, 8] and still existed in single-atom
dispersion status even through calcination at 800 °C with 3 vol.% water vapor for 5
days. However, the large Pt NPs would be formed under the same conditions only for
5 hours on unreconstructed Mn2O3 with single-atom Pt. These results can be confirmed
by x-ray diffraction (XRD), energy dispersive spectroscopy (EDS), aberration-
corrected scanning transmission electron microscopy (AC-STEM), diffuse reflectance
infrared Fourier transform spectroscopy (DRIFTS), X-ray absorption near edge
structure (XANES) and X-ray absorption fine structure (EXAFS). Additionally,
optimization through moderate H2O2 etching, the temperature-induced structure
reconstructed Pt-on-Mn2O3 SACs also showed the outstanding thermal stability and
stable catalytic activity in high-temperature methane oxidation.
Our previously reported redox precipitation method was applied to preload single-
atom Pt species on the as-obtained Mn3O4 and Mn2O3, denoted as Pt1/Mn3O4 and
4
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Pt1/Mn2O3, respectively.[9] Isolated Pt single atoms on both Mn3O4 and Mn2O3 are
initially detected by AC-STEM, where Pt species appear as highly-dispersed
distribution with high density on the surface of Mn3O4 and Mn2O3 and no Pt NCs or
NPs are observed in Pt1/Mn3O4 and Pt1/Mn2O3 (Figure 1A and 1C). CO-DRIFTS
spectra display the coverage-independent band at around 2099 cm-1 ascribed to CO
linearly bound to isolated Pt atoms on both Pt1/Mn3O4 and Pt1/Mn2O3 (Figure S1),
which indirectly proves the prevalence existence of single-atom Pt on catalyst
support.[10] Subsequent thermal treatment over both Pt1/Mn3O4 and Pt1/Mn2O3 was
carried out at high-temperature, as illustrated in Figure 1. Pt1/R-Mn2O3-5D was
obtained by calcining Pt1/Mn3O4 at 800°C in air with 3 vol.% water vapor for 5 days
and its AC-STEM image obviously shows the single-atom dispersion of Pt (Figure 1B),
which indicates the ultra-stability of Pt single atoms in the calcination process. Element
distribution images of Pt1/R-Mn2O3-5D display the uniform distribution of Pt element
in EDS mapping (Figure S2), which implies the highly-dispersed state of Pt species on
the support. XRD pattern collected for Pt1/R-Mn2O3-5D (Figure 2A) displays only the
characteristic peaks of Mn2O3 phase from high-temperature-induced reconstruction of
Mn3O4, which is in accordance with the phase change of pure support (Figure S3). No
Pt-phase characteristic peaks appear in XRD pattern, which also verifies only highly-
dispersed Pt species existed on Mn2O3. The interaction between single-atom Pt and
support in Pt1/Mn3O4 is extremely enhanced due to the generation of enough surface
defects and oxygen vacancies in conversion of Mn3O4 to Mn2O3, which can firmly trap
and confine single-atom Pt and result in ultra-thermal stable Pt single atoms on the
surface of Mn2O3 in Pt1/R-Mn2O3-5D. Conversely, non-reconstruction Mn2O3 as the
support cannot stabilize Pt species at single-atom dispersion. Only 5 hours treatment on
Pt1/Mn2O3 at 800°C in air with 3 vol.% water vapors to obtain PtNP/Mn2O3-5H, it leads
5
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
to single-atom Pt to migrate and agglomerate into large-size nanoparticle of about 13.8
nm (Figure 1D). It is also confirmed by XRD pattern of PtNP/Mn2O3-5H (Figure 2A),
in which a small peak assigned to lattice plane of Pt (111) appears at 2θ = 39.7o (JCPDF
no. 01-087-0646) and the grain size is calculated to be 11.8 nm by Scherrer equation.[1b]
EDS images of PtNP/Mn2O3-5H (Figure S4) reveal the presence of Pt NPs on the surface.
Thus, we can deduce that the reconstruction process of Mn3O4 to Mn2O3 firmly anchors
Pt species in single-atom status. Furthermore, this synthetic method also successfully
fulfils ultra-stable single-atom Pt species with high density on the support with very
low surface area, as obtained Mn2O3 and Mn3O4.
Figure 1. A) AC-STEM image of Pt1/Mn3O4. B) AC-STEM image of Pt1/R-Mn2O3-5D obtained via
calcining Pt1/Mn3O4 at 800oC in air with 3 vol.% water vapor for 5 days. C) AC-STEM image of
6
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Pt1/Mn2O3. D) HRTEM image of PtNP/Mn2O3-5H obtained via calcining Pt1/Mn2O3 at 800oC in air
with 3 vol.% water vapor for 5 hours.
XANES measurements (Figure 2B) confirm that the chemical state of Pt species
in Pt1/R-Mn2O3-5D strongly resembles PtO2, implying a high valence state of Pt4+
surrounded by oxygen and a larger population of unoccupied Pt 5d states for Pt ions in
Pt1/R-Mn2O3-5D.[7b, 11] Fourier transform radial distribution functions of k3-weight
EXAFS spectrum for Pt1/R-Mn2O3-5D (Figure 2C) shows a peak at around 1.60 Å from
the Pt-O contribution and no peak is observed for Pt-Pt bond contribution. Additionally,
a second shell peak at around 2.81 Å that is distanced from R values of Pt foil (2.38 Å)
and PtO2 (2.67 Å) is attributed to the Pt−Mn coordination in Pt1/R-Mn2O3-5D. As a
result, we deduced that Pt-O and Pt−Mn coordination are from the strong interaction
between the Pt atom and Mn2O3 due to the firm anchoring of high-valent single-atom
Pt on the surface or sub-surface of support via structure reconstruction, which
effectively inhibits migrating and sintering of Pt atom.[12]
Table 1: Summary of XPS Analysis
Pt species (Pt-4f) (%)[a]
Mn species (Mn-2p) (%)[a]
catalyst
Olatt/Oads
Pt4+
Pt2+
18.2
44.9
0.0
Pt0
Mn4+
16.1
16.7
17.1
22.3
Mn3+
22.2
50.6
60.2
51.2
Mn2+
61.7
32.7
22.8
26.5
Pt1/Mn3O4
Pt1/Mn2O3
0.70
1.52
2.11
2.09
81.8
55.1
0.0
0.0
Pt1/R-Mn2O3-5D
PtNP/Mn2O3-5H
100.0
54.7
0.0
17.1
28.3
[a] The relative contents of Pt, O and Mn species are calculated according to areas of simulated peaks in
Pt-4f7/2, O-1s and Mn-2p5/2 regions, respectively.
XPS patterns (Figure 2D) of Pt-4f for Pt1/Mn3O4 and Pt1/Mn2O3 show the four
well-fitted peaks with binding energies of 77.9, 75.8, 74.5 and 72.4 eV, which are
attributed to Pt4+4f5/2, Pt2+4f5/2, Pt4+4f7/2, and Pt2+4f7/2, respectively. After high-
7
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
temperature calcination, the derived Pt1/R-Mn2O3-5D only remains two peaks at
around 78.2 and 74.8 eV from the spin-orbital split of Pt4+, which indicates that high-
temperature treatment leads to complete conversion of Pt2+ to Pt4+ (Table 1).[13] For
PtNP/Mn2O3-5H, more complicate chemical valence of Pt in XPS Pt-4f curve are
observed that displays the inherited Pt4+ and Pt2+ peaks and a new metallic Pt0 species
with the binding energies of 74.3 and 71.1 eV. Synchronously, an obvious increasing
ratio of Mn3+ in Mn-2p XPS of Pt1/R-Mn2O3-5D (Figure S5 and Table 1) explains the
occurrence of structure reconstruction of support from Mn3O4 to Mn2O3. However, the
XPS ratio of Mn3+ in PtNP/Mn2O3-5H keeps the same level with Pt1/Mn2O3, which
suggests Mn2O3 support is more stable under calcination. Structure reconstruction of
support causes that surface dispersed Pt single atoms of Pt1/Mn3O4 are deeply confined
on the surface or subsurface of Mn2O3 in Pt1/R-Mn2O3-5D during calcination. It
facilitates the generation of more Pt-O bonds between single-atom Pt and O of Mn2O3
and convert all Pt2+ to Pt4+, which further enhances the interaction between Pt and
Mn2O3 to stabilize the single-atom structure at least for 5 days. Due to lack of
confinement effect, a large amount of Pt4+ and Pt2+ existed on the surface of Pt1/Mn2O3
at elevated temperature easily generates the volatile gaseous PtO2 that can depart from
the surface of support and trap each other to form larger NPs (Ostwald Ripening).[7b] It
is also confirmed by HRTEM and XRD analysis of PtNP/Mn2O3-5H, which is quite
consistent with the sintering of Pt to NPs on support after high-temperature
calcination.[6, 14] Based on analysis of XPS data, Pt/Mn ratios on the surface of
Pt1/Mn3O4 and Pt1/R-Mn2O3-5D are calculated, which display an obvious decreasing
of surface Pt content from 2.7:97.3 of Pt1/Mn3O4 to 0.7:99.3 of Pt1/R-Mn2O3-5D via
calcination (Table S1). However, inductively coupled plasma-optical emission
spectroscopy (ICP-OES) results of Pt contents in Pt1/Mn3O4 and Pt1/R-Mn2O3-5D
8
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
express that they have the same Pt loading of 0.82 wt% in the bulk (Table S1). This
discrepancy comes from that structure reconstruction of support makes some Pt single
atoms locate in sub-surface region of support and is beyond the scope of XPS detection.
The very close Pt contents of ICP-OES result for Pt1/Mn2O3 and PtNP/Mn2O3-5H prove
that Pt has not been noticeably lost in vaporization depletion via the path of volatile
PtO2 at high-temperature.
Figure 2. A) XRD patterns of samples in full range. Except PtNP/Mn2O3-5H, no peaks corresponding
to Pt species are observed for the other samples. The inset showing an obvious peak at 39.7o from
Pt (111) in the curve of PtNP/Mn2O3-5H confirms the existence of Pt NPs. B) Pt LIII XANES
spectrum of Pt1/R-Mn2O3-5D alongside PtO2 and Pt foil references. C) Fourier transform radial
distribution function of the Pt LIII-edge k3-weighted EXAFS spectra of Pt1/R-Mn2O3-5D in
9
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
comparison with PtO2 and Pt foil. D) Pt-4f XPS spectra of Pt1/Mn3O4, Pt1/R-Mn2O3-5D, Pt1/Mn2O3
and PtNP/Mn2O3-5H.
The cationic oxidation state on transition metal oxides can be changed during
structure reconstruction especially for Mn cation with multiple oxidation states.[15]
Temperature-induced structure reconstruction in air inserts more oxygen species into
crystal phase structure of Mn3O4 during the irreversible phase transition of Mn3O4 to
Mn2O3 due to charge compensation in the conversion of low-valence Mn ions to high-
valence Mn ions. In this process, the originally ordered structure of Mn3O4 is destroyed,
which inevitably forms surface deformation and generates structure defects to firmly
confine the already-existed Pt single atoms. It finally results in the formation of the
strong interaction between Pt atoms and support by more coordination bonds of Pt4+
and oxygen as well as surface-layer confinement.
Generally, noble metal species of supported noble metal catalyst as catalytic sites
plays a key role in catalytic reaction. Thus, to expose more single-atom Pt catalytic sites
in Pt1/R-Mn2O3-5D, chemical etching by H2O2 to react with MnOx to form water-
soluble Mn2+ was used to prepare xH2O2-Pt1/R-Mn2O3-5D (x = 0.25, 0.5, 1.0 mL) based
on our previous research (Figure 3A).[9a] No change can be obviously observed in XPS
results after treatment by different amount of H2O2 except the gradually enhanced
intensity of Pt4+ signals (Figure S6 and Table S2), which reflects surface Pt single atoms
are increasingly exposed accompanying with the removal of covered MnOx.
CO-DRIFTS of xH2O2-Pt1/R-Mn2O3-5D show the coverage-independent band at
around 2080-2095 cm-1 (Figure 3B), which is the only feature attributed to CO linearly
bound to isolated Pt atoms.[1b, 16] The raised intensity of the peak with increasing H2O2
10
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
amount explains that more Pt single atoms appear on the surface of Mn2O3 after H2O2
treatment and linearly coordinate with more CO. ICP-OES results confirm that samples
still keep very close Pt contents although through H2O2 etching (Table S1), indicating
single-atom Pt on Mn2O3 are not easily washed off.
Figure 3. A) H2O2 etching to remove Mn oxides covered on Pt single atoms. B) DRIFTS spectra of
Pt1/R-Mn2O3-5D and xH2O2-Pt1/R-Mn2O3-5D. C), D) CH4 conversion (C) and CO2 yield (D) on
Pt1/R-Mn2O3-5D, xH2O2-Pt1/R-Mn2O3-5D and Mn2O3.
We test the catalytic activity of methane oxidation on catalyst to verify whether
the catalyst etched by H2O2 show higher catalytic reactivity. High-temperature catalytic
11
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
behavior of CH4 oxidation on xH2O2-Pt1/R-Mn2O3-5D (Figure 3C and 3D) presents that
0.5H2O2-Pt1/R-Mn2O3-5D owns the best catalytic activity for CH4 oxidation with 50%
of conversion at 518oC (T50%) and 90% of conversion at 603oC (T90%), which are more
super than untreated Pt1/R-Mn2O3-5D (T50% = 546oC and T90% = 639oC ) and much
better than pure Mn2O3 (T50% = 580oC and T90% = 694oC) (Table S3). Noticeably, more
H2O2 addition in preparation of xH2O2-Pt1/R-Mn2O3-5D is helpless to further promote
catalytic activity. As observed for 1.0H2O2-Pt1/R-Mn2O3-5D, it shows the slightly less
catalytic activity than that of 0.5H2O2-Pt1/R-Mn2O3-5D. It manifests moderate exposed
Pt single atoms as well as synchronously owning the optimized strong Pt-support
interaction on the surface of Mn2O3 can facilitate CH4 catalytic oxidation. Actually, it
is limited to distinguish the characteristic difference in these catalysts. As a comparison
with Pt1/R-Mn2O3-5D, 0.5H2O2-Pt1/R-Mn2O3-5D is almost unchanged in properties of
XRD, AC-STEM, XANES and EXAFS (Figure 4B, 4D, 4G and Figure S7) except the
intensity of XPS Pt4+ peaks (Figure 4E).
We also performed the cycle experiment of CH4 oxidation on 0.5H2O2-Pt1/R-
Mn2O3-5D at alternative reaction temperatures for 3 cycles (700 and 500oC, each
temperature stage for 10 h, Figure 4A), exhibiting the stable catalytic activity in both
high and low conversions for at least 60 h. The structure stability of 0.5H2O2-Pt1/R-
Mn2O3-5D in oxidation reaction is investigated by analysis of AC-STEM, XANES,
EXAFS, XPS, XRD and ICP-OES before and after the cycle experiment. After 60-hour
reaction, the used catalyst 0.5H2O2-Pt1/R-Mn2O3-5D-Used still retains the single-atom
dispersed Pt on Mn2O3 imaged in AC-STEM (Figure 4B and 4C), the same coordination
sphere and valence state of Pt with 0.5H2O2-Pt1/R-Mn2O3-5D (Figure 4D-4G), and the
almost same XRD pattern and Pt content of ICP-OES with 0.5H2O2-Pt1/R-Mn2O3-5D
(Figure S7 and Table S1). These results confirm that the catalyst
12
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
0.5H2O2-Pt1/R-Mn2O3-5D has an outstanding structure stability even through the harsh
high-temperature reaction. Compared with the reported Pt catalysts (Table S4),
0.5H2O2-Pt1/R-Mn2O3-5D with the lowest Pt loading has relatively good catalytic
activity for methane oxidation and long-term catalytic stability for both low and high
conversions, which is ascribed to single atom distribution of Pt and strong confinement
effect of Pt atoms on the surface of support.
Figure 4. A) 60-hour high-temperature reaction stability test on 0.5H2O2-Pt1/R-Mn2O3-5D at 700
and 500 oC with different conversions. B), C) AC-STEM images of 0.5H2O2-Pt1/R-Mn2O3-5D (B)
and 0.5H2O2-Pt1/R-Mn2O3-5D-Used (C). D) Pt LIII XANES spectra of 0.5H2O2-Pt1/R-Mn2O3-5D
and 0.5H2O2-Pt1/R-Mn2O3-5D-Used. E), F) XPS spectra collected at the Pt-4f on the 0.5H2O2-Pt1/R-
13
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Mn2O3-5D (E) and 0.5H2O2-Pt1/R-Mn2O3-5D-Used (F). G) Fourier transform radial distribution
function of the Pt LIII-edge k3-weighted EXAFS spectra of 0.5H2O2-Pt1/R-Mn2O3-5D and
0.5H2O2-Pt1/R-Mn2O3-5D-Used.
In summary, structure reconstruction to anchor single-atom noble metals is an
efficient approach to obtain high-thermal stable SACs. As a common phenomenon, the
phase transition of materials is structure reengineering process, which can achieve by
various means. In our research, temperature-induced phase transition process from
Mn3O4 to Mn2O3 is a critical prerequisite to firmly confine the existed surface single-
atom Pt species on support, which dramatically promotes the Pt-support interaction and
ensures Pt species with a stable single-atom dispersion status in catalyst. The as-
synthesized Pt1/R-Mn2O3-5D maintains the single-atom stability after calcination at
800 °C in air with water vapor for at least 5 days. Not only that, it also exhibits the
outstanding structure stability via harsh high-temperature catalytic behavior of CH4
oxidation on xH2O2-Pt1/R-Mn2O3-5D optimized by moderate H2O2 etching. Thus,
support reconstruction provides a new direction to successfully solves the problem of
the instability for noble-metal SACs at high-temperature.
Acknowledgments
This work was support from the National Natural Science Foundation of China
(21976172 and 21806162), the Key Research Program of Frontier Sciences, CAS
(QYZDB-SSW-DQC022), the Science and Technology Planning Project of Fujian
Province (2019Y0074), and the FJIRSM&IUE Joint Research Fund (RHZX-2018-002).
We thank Dr Yu Wang for measurement and helpful discussions of XAFS.
Conflict of interest
The authors declare no competing interests.
14
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Keywords: single-atom catalyst • Pt • thermal stability • structure reconstruction •
strong interaction
[1]
a) B. Qiao, A. Wang, X. Yang, L. F. Allard, Z. Jiang, Y. Cui, J. Liu, J. Li, T.
Zhang, Nat. Chem. 2011, 3, 634-641; b) J. Jones, H. F. Xiong, A. T. Delariva,
E. J. Peterson, H. Pham, S. R. Challa, G. S. Qi, S. Oh, M. H. Wiebenga, X. I. P.
Hernandez, Y. Wang, A. K. Datye, Science 2016, 353, 150-154; c) A. Wang, J.
Li, T. Zhang, Nat. Rev. Chem. 2018, 2, 65-81; d) L. Liu, A. Corma, Chem. Rev.
2018, 118, 4981-5079; e) Q. Zuo, T. Liu, C. Chen, Y. Ji, X. Gong, Y. Mai, Y.
Zhou, Angew. Chem. 2019, 58, 10198-10203.
[2]
[3]
J. M. Thomas, Nature 2015, 525, 325-326.
a) P. Xie, T. Pu, A. Nie, S. Hwang, S. C. Purdy, W. Yu, D. Su, J. T. Miller, C.
Wang, ACS Catal. 2018, 8, 4044-4048; b) Y. Qu, B. Chen, Z. Li, X. Duan, L.
Wang, Y. Lin, T. Yuan, F. Zhou, Y. Hu, Z. Yang, C. Zhao, J. Wang, C. Zhao,
Y. Hu, G. Wu, Q. Zhang, Q. Xu, B. Liu, P. Gao, R. You, W. Huang, L. Zheng,
L. Gu, Y. Wu, Y. Li, J. Am. Chem. Soc. 2019, 141, 4505-4509.
a) T. W. Hansen, A. T. Delariva, S. R. Challa, A. K. Datye, Acc. Chem. Res.
2013, 46, 1720-1730; b) W. Yuan, D. Zhang, Y. Ou, K. Fang, B. Zhu, H. Yang,
T. W. Hansen, J. B. Wagner, Z. Zhang, Y. Gao, Y. Wang, Angew. Chem. 2018,
57, 16827-16831.
[4]
[5]
a) X. F. Yang, A. Q. Wang, B. T. Qiao, J. Li, J. Y. Liu, T. Zhang, Acc. Chem.
Res. 2013, 46, 1740-1748; b) X. Yang, Q. Li, E. Lu, Z. Wang, X. Gong, Z. Yu,
Y. Guo, L. Wang, Y. Guo, W. Zhan, J. Zhang, S. Dai, Nat. Commun. 2019, 10,
1611.
[6]
[7]
F. Dvorak, M. Farnesi Camellone, A. Tovt, N. D. Tran, F. R. Negreiros, M.
Vorokhta, T. Skala, I. Matolinova, J. Myslivecek, V. Matolin, S. Fabris, Nat.
Commun. 2016, 7, 10801
a) S. Wei, A. Li, J. C. Liu, Z. Li, W. Chen, Y. Gong, Q. Zhang, W. C. Cheong,
Y. Wang, L. Zheng, H. Xiao, C. Chen, D. Wang, Q. Peng, L. Gu, X. Han, J. Li,
Y. Li, Nat. Nano. 2018, 13, 856-861; b) R. Lang, W. Xi, J. C. Liu, Y. T. Cui, T.
15
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Li, A. F. Lee, F. Chen, Y. Chen, L. Li, L. Li, J. Lin, S. Miao, X. Liu, A. Q.
Wang, X. Wang, J. Luo, B. Qiao, J. Li, T. Zhang, Nat. Commun. 2019, 10, 234.
N. Daelman, M. Capdevila-Cortada, N. López, Nat. Mater. 2019, 18, 1215-1221.
a) J. Chen, M. Jiang, W. Xu, J. Chen, Z. Hong, H. Jia, Appl. Catal. B-Environ.
2019, 259, 118013; b) J. Chen, D. Yan, Z. Xu, X. Chen, X. Chen, W. Xu, H. Jia,
J. Chen, Environ. Sci. Technol. 2018, 52, 4728-4737.
[8]
[9]
[10] H. Wang, J. X. Liu, L. F. Allard, S. Lee, J. Liu, H. Li, J. Wang, J. Wang, S. H.
Oh, W. Li, M. Flytzani-Stephanopoulos, M. Shen, B. R. Goldsmith, M. Yang,
Nat. Commun. 2019, 10, 3808.
[11] L. DeRita, J. Resasco, S. Dai, A. Boubnov, H. V. Thang, A. S. Hoffman, I. Ro,
G. W. Graham, S. R. Bare, G. Pacchioni, X. Pan, P. Christopher, Nat. Mater.
2019, 18, 746-751.
[12] H. Zhang, S. Sui, X. Zheng, R. Cao, P. Zhang, Appl. Catal. B-Environ. 2019,
257, 117878.
[13] D. Kunwar, S. Zhou, A. DeLaRiva, E. J. Peterson, H. Xiong, X. I. Pereira-
Hernández, S. C. Purdy, R. ter Veen, H. H. Brongersma, J. T. Miller, H.
Hashiguchi, L. Kovarik, S. Lin, H. Guo, Y. Wang, A. K. Datye, ACS Catal.
2019, 9, 3978-3990.
[14] A. Bruix, Y. Lykhach, I. Matolinova, A. Neitzel, T. Skala, N. Tsud, M.
Vorokhta, V. Stetsovych, K. Sevcikova, J. Myslivecek, R. Fiala, M. Vaclavu,
K. C. Prince, S. Bruyere, V. Potin, F. Illas, V. Matolin, J. Libuda, K. M. Neyman,
Angew. Chem. 2014, 53, 10525-10530.
[15] C. Y. Ouyang, Z. Sljivancanin, A. Baldereschi, J. Chem. Phys. 2010, 133,
204701.
[16] O. Pozdnyakova, D. Teschner, A. Wootsch, J. Krohnert, B. Steinhauer, H. Sauer,
L. Toth, F. Jentoft, A. Knopgericke, Z. Paal, J. Catal. 2006, 237, 1-16.
16
This article is protected by copyright. All rights reserved.

10.1002/anie.202004929
Angewandte Chemie International Edition
Entry for the Table of Contents
Accompanying with phase transition of support, surface reconstruction process solidly
confines Pt single atoms to form enhanced strong interaction of Pt and support, which
restrains noble metal atoms to aggregate and evaporate at high-temperature. The
resulting single-atom noble metal catalyst exhibits excellent thermal stability both at
800oC in the humid air for 5 days or in high-temperature CH4 catalytic combustion.
17
This article is protected by copyright. All rights reserved.