Catalytic decomposition and mechanism of formaldehyde over Pt-Al2O3 molecular sieves at room temperature

Article abstract of DOI:10.1039/c6cp08223h

To overcome the drawbacks of powder-like catalysts in practical application, an Al₂O₃ molecular sieve supported Pt (Pt-Al₂O₃) catalyst was prepared by the impregnation method combined with dilute hydrochloric acid solution pretreatment. The role of the pretreatment solution in catalyst preparation and formaldehyde (HCHO) decomposition over Pt-Al₂O₃ catalysts was investigated. The acid solution with pH = 1 was optimal for Pt dispersion on the Al₂O₃ surface. The Pt-Al₂O₃ catalyst was capable of achieving complete and stable HCHO oxidation at ambient temperature. In addition, the excellent activity for HCHO removal was promoted by the mesoporous structure, large specific surface area and high adsorption ability of Al₂O₃ molecular sieves, as determined by N₂-sorption studies. Dioxymethylene (DOM) and formate species were identified as major intermediates by in situ DRIFTS studies. These intermediates were subsequently oxidized into CO₂ and H₂O at ambient temperature. Moreover, a possible reaction mechanism of HCHO removal and a regeneration pathway of surface hydroxyls were proposed. This study provides new insights into the preparation of practical, low-cost catalysts for indoor air purification.

Full text of DOI:10.1039/c6cp08223h

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DOI: 10.1039/C6CP08223H
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Catalytic decomposition and mechanism of formaldehyde over Pt-
Al2O3 molecular sieves at room temperature
Xiaofeng Zhu,a Jiaguo Yu,a,b,* Chuanjia Jianga,* and Bei Chenga
Received 00th Janu ary 20xx,
Accepted 00th January 20xx
To overcome the drawbacks of powder-like catalysts in practical application, Al2O3 molecular sieve supported Pt (Pt-Al2O3)
catalyst was prepared by the impregnation method combined with dilute hydrochloric acid solution pretreatment. The
role of the pretreatment solution in catalyst preparation and formaldehyde (HCHO) decomposition over Pt-Al2O3 catalysts
DOI: 10.1039/x0xx00000x
www.rsc.org/
was investigated. It was found that the acidsolution with pH=1 was optimal for Pt dispersion on Al2O3 surface. The Pt-Al2O
3
catalyst was capable of achieving complete and stable HCHO oxidationatambient temperature. Also, the excellent activity
for HCHO removal was promoted by the mesoporous structure, large specific surface area and high adsorption ability of
Al2O molecular sieves as determined by N2-sorption studies. Dioxymethylene (DOM) and formate species were identified
3
as major intermediates by in situ DRIFTS studies. These intermediates were subsequently oxidized into CO2 and H2O at
ambient temperature. Moreover,a possible reaction mechanism of HCHO removal and a regeneration pathway of surface
hydroxyls were proposed. This work provides new thoughts into preparing practical low-cost catalysts for indoor air
purification.
et al. found that formaldehyde could be decomposed into H2O and
CO2 at room temperature by 1wt% Pt-TiO2, and Pt loading would
Introduction
significantlyaffect the activity of the catalyst.22,23 An et al. prepared
a Fe2O3-supported Pt which showed stable and efficient activity for
completely oxidizing HCHO at ambient temperature after
appropriate calcinations.37 In addition, Nie et al. synthesized
hierarchically macro-mesoporous Al2O3 hollow spheres as the
Indoor air pollution is becoming a critical issue impacting public
health, especially by the volatile organic compounds (VOCs).1−3
Among reported VOCs, formaldehyde (HCHO) has been recognized
as one of the most harmful indoor pollutants, as it is commonly
emitted from building and furnishing materials as well as consumer
products,4−7 causing multiple healthy problems including eye and support for Pt deposition, and the Pt-Al 2O3 catalysts showed
skin irritation, headache, nasal tumors, and even cancer.8,9
efficient performance of HCHO decomposition at room
Therefore, many strategies have been developed to eliminate
temperature.38 Also, Yan et al. utilized micro-emulsion method to
HCHO to meet the environmental regulation requirements and
human health needs. For instance, physical and chemical
adsorption,10−12 photocatalytic oxidation,13−15 thermal catalytic
oxidation,16−19 and plasma-assisted oxidation20,21 have been
prepare Pt-ferrihydrite catalysts, achieving over 90% of room-
temperature HCHO conversion.39 However, despite their superior
catalytic activity, one major disadvantage of these catalysts for
practical applications and commercialization is assigned to the
developed to abate the HCHO pollution. However, adsorption powder form of these reported catalysts, which makes them
difficult to transport, distribute and recycle.40 In this respect, it is
strategies have been restricted by their limited adsorption
capability, and photocatalytic, plasma and thermal oxidation
technologies need extra apparatuses, such as light sources, plasma
generators and heating devices.
desirable to prepare catalysts on porous materials with
macroscopic bulk geometries, such as monoliths, foams, fibers and
granules.40−42
Recently, room-temperature catalytic oxidation has been
As one of the most important industrial materials, alumina
recognized as one of the most promising and efficient methods for (Al2O3) is widely used as ceramics, coatings, catalyst support, filler,
HCHO removal with no harmful byproduct generation.22−25 Among
refractory, abrasive, and medicinal materials due to its excellent
previous catalysts, platinum-deposited metal oxides have exhibited
good performance in HCHO decomposition.26−36 For example, Zhang
chemical stability, porous structure, abundant reserves and low
cost.43−45 Al 2O3-based catalysts therefore have been commonly
utilized in many industrial processes, for instance, selective CO
hydrogenation46 and oxidation,47 aqueous-phase reforming of
methanol and ethylene glycol,48 and oxidation of various aliphatic
and aromatic hydrocarbons (e.g. propane, n-hexane benzene and
toluene).49,50 Among the myriad Al2O3 products, pellet-shaped Al2O3
molecular sieves are widely used as adsorbents and desiccants in
a. State Key Lab orato ry of Ad vanced Technology fo r Materials Synthesis and
Processing, Wuhan University of Technology, Wuhan, 430070, Chin a. Fax: +86-27-
87879428; Tel: +86-27-87871029; E-mail: jiaguoyu@yahoo.com (J. Yu);
jiangcj2016@yahoo.com (C. Jiang)
b. Department of Physics , Faculty of Science, King Abdulaziz Unive rsity, Jeddah
21589, Saudi A rabia.
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industrial processes, but not as frequently used in catalysis, were measured by inductively coupled plasma atomic emission
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DOI: 10.1039/C6CP08223H
especially in catalytic oxidation of VOCs such as HCHO. Thus, it is spectrometry (ICP-AES) after digestion of the samples in aqua regia.
worth exploring the possibility of utilizing Al 2O3 molecular sieves as
catalystsupport for practical HCHO oxidation removal.
The Brunauer-Emmett-Teller (BET) specific surface area (SBET
of each sample was measured by a Micromeritics TriStar II 3020
)
In this study, Al2O3 molecular sieves pretreated with dilute surface area and porosity analyzer; nitrogen (N2) adsorption data
hydrochloric acid (HCl) solutions were used as support to deposit Pt between the relative pressure (P/P0) of 0.05 and 0.3 were utilized in
nanoparticles (NPs) by a facile impregnation method. The as - a multipoint BET method. By using the N2 adsorption volume at a
prepared catalysts exhibited good catalytic activity, stability and P/P0 of 0.98, the pore volume (Vpore) and the average pore size (dpore
applicability for HCHO decomposition. Additionally, the of Pt-Al 2O3 samples were also estimated. The pore-size distribution
physicochemical properties of the catalysts were characterized by was also calculated using the Barret-Joyner-Halender (BJH) method.
)
various techniques, and the effect of acid solution pretreatment
The dispersion of Pt was evaluated by a carbon monoxide
was examined. Furthermore, the mechanism of HCHO chemisorption on BELCAT-B-293 Catalyst Analyzer (Bel, Japan); a
decomposition over the catalysts and the regeneration of surfa ce thermal conductivity detector (TCD) was used to determine the CO
hydroxyls were investigated, in order to guide the design of highly consumption. The sample (50 mg) was loaded into a U-shaped
efficient and stable HCHO oxidation catalysts.
quartz tube and was heated to 200 °C under helium flow (50
mL/min) for 35 min prior to the injection of CO (CO/He, 10%) pulses
at 50 °C. In situ diffuse reflectance infrared Fourier transform
spectra (DRIFTS) were recorded on Thermo Fisher Nicolet 6700
infrared spectrometer. The samples were firstly pretreated in air
flow at 150 °C for 1 h in an in situ cell reactor. Afterwards, a mixed
gas flow of O2 and 80 ppm formaldehyde with a rate of 30 mL/min
was injected to the cell reactor through separate mass flow meters
at ambient temperature. A background spectrum was subtracted
from each spectrum, and all spectra were measured with a
Experimental section
Preparation of Pt-Al2O3 catalysts
The Pt-Al 2O3 catalysts were prepared via the impregnation method.
All reagents were of analytical grade without further purification.
Firstly, commercial spherical Al 2O3 molecularsieves with a diameter
of ca. 0.4 cm were washed with ethanol and deionized water to
remove residual compounds on the surface. Then, 1 g of Al 2O3
molecular sieve was immersed in 5 mL of HCl solution with different
acidities (pH = 1, 3, 5 and 7), and labeled as AO1, AO3, AO5 and AO7,
respectively. The molecular sieves were treated in HCl for 30 min,
followed by the slow injection of 0.5 mL H2PtCl6 (19.3 mM) solution
under magnetic stirring. After 1 h, 5 mL mixed solution of NaBH4
(0.1 M) and NaOH (0.5 M) was quickly injected into the mixture,
which was vigorously stirred for 2 h. Subsequently, the samples
were harvested and washed with deionized water for six times to
eliminate the poisoning effect of Cl − ions.51 The washed samples
were dried at 80 °C for 10 h, and annealed in air at 350 °C for 2 h
with a heating rate of 2 °C/min. The as -obtained Pt-Al 2O3 catalysts
were denoted as Pt-AO1, Pt-AO3, Pt-AO5,and Pt-AO7, respectively.
resolution of 4 cm−1
.
Catalytic activity tests
The HCHO catalytic decomposition over Pt-Al 2O3 catalyst was
performed in an organic glass reactor (inner volume is 6 L and
aluminum foil-covered inner wall) at room temperature. The as-
prepared sample (0.5 g) was placed on the bottom of a glass Petri
dish covered by a glass slide. The dish was placed in the reactor,
and a proper volume of HCHO solution (38%) was quicklyadded to
obtain a stable concentration of gaseous HCHO at ca. 250 ppm in
the reactor; a 5-W fan in the reactor was used to promote gas
dispersion. Concentrations of HCHO, CO2, and CO were on-line
detected by a Photoacoustic Field Gas Monitor (INNOVA AirTech
Instruments, Model 1412). After the concentration of each gas
reached equilibrium, the glass slide was removed to trigger the
Characterization
The component and crystal structure of the as-prepared Pt-Al 2O3 tests. The HCHO removal was estimated via following calculation:
[HCHO] [HCHO]
samples were analyzed by X-ray diffraction (XRD) on X-ray
diffractometer (Rigaku, Japan) with Cu Kα radiation at a scan rate of
0.05° 2θ s−1. The morphology and elemental composition of the
samples were investigated by scanning electron microscopy (SEM)
I
HCHOremoval(%)
F 100%
[HCHO]
I
where [HCHO]I (ppm) and [HCHO]F (ppm) is the initial and final
equilibrium concentration of HCHO measured during the HCHO
(JSM-7500 JEOL, Japan) and its EDS apparatus (X-MAXn Oxford, UK) decomposition test.
with an accelerating voltage of 10 kV and a probe current of 10 nA.
Transmission electron microscopy (TEM) images with the high-
Results and discussion
resolution pattern of the catalysts were obtained on a JEM-2100F
electron microscope (JEOL, Japan) with an accelerating voltage of
200 kV. Also, X-ray photoelectron spectroscopy (XPS) analysis were
conducted on a Kratos XSAM800 XPS system with Al Kα source and a
charge neutralizer; all the binding energies were referenced to the
C 1s peak of the surface adventitious carbon at 284.8 eV. With a
nominal Pt loading of 0.1 wt%, the actual Pt loadings of the samples
Characterization of catalysts
The XRD patterns of all samples are shown in Fig. 1. The primary
peaks at 2θ = 27.3° (3 1 1), 42.9° (3 2 1), 45.9° (4 0 0), 61.5° (5 1 1),
and 66.8° (4 4 1) correspond to the characteristic diffraction peaks
of χ-Al 2O3 (JCPDS No. 04−0880),52 and no peaks of other minerals
were observed in all samples, indicating their relatively high purity.
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Besides, XRD patterns of Pt-AO1, Pt-AO3, Pt-AO5, and Pt-AO7
samples are similar to that of the AO sample, suggesting that Pt
deposition had no impact on the crystal structure of the samples.
No characteristic peaks corresponding to Pt were discernible in the
XRD patterns, majorly owing to the high dispersion of Pt NPs and
the lowloading in the studied samples.32
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DOI: 10.1039/C6CP08223H
Fig.3 TEM (a) and HRTEM (b) images of the Pt-AO1 sample.
The pore structure and texture of the AO, Pt-AO1, Pt-AO3, Pt-
AO5, and Pt-AO7samples were determinded by N2 sorption analysis.
The N2 sorption isotherms and the corresponding pore -size
distribution curves of the catalysts are exhibited in Fig. 4 and its
inset. All the sorption isotherms are type IV with H2-type hysteresis
loops based on International Union of Pure and Applied Chemistry
(IUPAC) classification,53 suggesting the presence of ink bottle-like
mesopores, which is also in accordance with the TEM results. The
pore-size distribution curves calculated for AO and Pt-AO (inset in
Fig. 4) are mostly in the range of 3−10 nm, further implying the
presence of mesopores. Moreover, compared with the N2 sorption
isotherms and the pore-size distribution of AO, those of Pt-AO1, Pt-
AO3, Pt-AO5, and Pt-AO7 show no obvious differences, suggesting
that the general pore structure can be well maintained after the
deposition of Pt NPs. As expected, both Pt-AO1 and Pt-AO3 samples
have slightlylarger Vpore (0.59 and 0.56 cm3/g)and SBET (294 and 292
m2/g) than those of AO (0.52 cm3/g and 278 m2/g) (Table 1), mainly
due to the erosion of Al2O3 molecularsieves bydilute HCl during the
acid pretreatment and preparation. However, the SBET (265 and 257
m2/g) of Pt-AO5 and Pt-AO7 samples were smaller than those of AO,
dominantly resulting from the blocking effect of deposited Pt NPs.
Generally, the larger specific surface area and pore volume could
provide more adsorption and reactive sites in HCHO oxidation and
facilitate the deposition of Pt, which consequently results in
enhanced decomposition activity.
Fig. 1 XRD patterns of AO, Pt-AO1, Pt-AO3, Pt-AO5,and Pt-AO7samples.
As shown in Fig. 2, SEM and EDS elemental analyses of Pt-AO1
confirm the existance of highly dispersed Pt NPs on the surface of
Al2O3 molecular sieves. Additionally, TEM images (Fig. 3) show the
microstructure of the grated Pt-AO1 sample, indicating that the
Al2O3 molecular sieves were assembled with nanoparticles. Besides,
the TEM images reveal that Pt NPs were highly dispersed on the
surface of the Al2O3 nanoparticles with an average diameter of 3−4
nm, increasing the number of active sites for the same Pt loading.
Meanwhile, the HRTEM images demonstrate that the lattice spacing
of the Pt NPs is ca. 0.221 nm (Fig. 3b), which is consistent with that
of metallic Pt (1 1 1) planes,38,39 further indicating the presence of
metallic Pt NPs.
Fig. 4 Nitrogen adsorption-desorption isotherms and corresponding pore
Fig. 2 SEM image and EDS mapping patterns of the Pt-AO1 sample (Al Kα, O
size distribution curves (inset) for AO, Pt-AO1, Pt-AO3, Pt-AO5, and Pt-AO7.
Kα,and Pt Mα).
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Table 1. Properties of the AO, Pt-AO1, Pt-AO3, Pt-AO5,and Pt-AO7 samples. a
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DOI: 10.1039/C6CP08223H
Pt dispersion
Sample
SBET (m2/g)
Vpore (cm3/g)
dpore (nm)
Pt wt%
TOF (min−1)
(%)
AO
278
294
292
265
257
0.52
0.59
0.56
0.53
0.51
7.4
7.7
8.0
8.1
8.0
N/A
N/A
38.4
36.6
35.1
35.0
N/A
1.07
0.95
0.91
0.91
Pt-AO1
Pt-AO3
Pt-AO5
Pt-AO7
0.088
0.090
0.095
0.089
a SBET, BET specific surface area; Vpore, single-point pore volume; and dpore, average pore size.
The XPS measurements of the Pt-AO1 and AO samples were
carried out to analyze the chemical states of their surface elements
(Fig. 5). The deconvolution of the O 1s profiles (Fig. 5a) reveals a
minor peak at 533.0 eV and a main peak at 531.3 eV, which can be
assigned to the oxygen of surface hydroxyl group and the lattice
oxygen of Al2O3 in both Pt-AO1 and AO.52 Besides, one principal
peak of Al 2p of the Pt-AO1 was observed at 74.4 eV (Fig. 5b), with a
slight decrease in binding energy as compared with that of the AO
sample (74.6 eV).52 The negative shift suggests the presence of
electrons transfer from the deposited Pt to surface Al via the
surface oxygen atoms, which results from the interaction between
metallic Pt and Al2O3 molecular sieves.54,55 Unfortunately, the
identification and quantification of metallic Pt species could not be
achieved, due to the close bindingenergy values of Pt 4f5/2 (74.5 eV)
and Al 2p.38,56
HCHO catalytic decomposition
The catalytic HCHO removal by Pt-AO1, Pt-AO3, Pt-AO5, and Pt-AO7
after 1 h of reaction at room temperature is shown in Fig. 6.
According to the results in Fig. 6, the Pt-AO1 sample showed
superior HCHO oxidation and CO2 yield, followed by Pt-AO3, Pt-AO5,
and Pt-AO7 samples, which is well consistent with their Pt
dispersions. The result indicates that high Pt dispersion of catalysts
contributes to the enhanced HCHO decomposition activity.51
Meanwhile, as shown in Table 1, the calculated turnover frequency
(TOF) for HCHO oxidation of Pt-AO1 was 1.07 min−1, which was
slightly higher than that of Pt-AO3 (0.95 min−1), Pt-AO5 (0.91 min−1),
and Pt-AO7 (0.91 min−1), respectively. Given that the Pt content was
almost the same for each catalyst, higher Pt dispersion enhance d
the interaction between Pt NPs and the Al 2O3 support, which may
improve the activity of each reactive site.54,55 Thus, the HCHO
decomposition activity of Pt-AO1 catalyst was higher than that of
Pt-AO3, Pt-AO5, and Pt-AO7. Particularly, Pt dispersion data of
these four catalysts declined with the decreasing acidity of HCl
solution in pretreatment, suggesting that the Pt dispersion of the
sample is significantly influenced by the treatment of acid solution
before the impregnation. We propose an explanation that H+ ion
would adsorb on Al2O3 surface during the pretreatment by the HCl
solution, and the adsorbed H+ subsequently attract the [PtCl6]2−
through electrostatic effects, thus promoting the dispersion of Pt
NPs in the reduction process.
Fig. 6 HCHO removal and corresponding CO2 yield over Pt-AO1, Pt-AO3, Pt-
AO5, and Pt-AO7 samples.
Fig. 5 High resolution XPS spectra for (a) O 1s and (b) Al 2p of the Pt-AO1
and AO samples.
Catalytic stability
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The stability of HCHO decomposition over the Pt-AO1 was 2ω(CH2) of dioxymethylene (DOM),31 respectively. Additionally, the
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evaluated through five recycle tests. As shown in Fig. 7, there was peak at 2545 cm−1 can be ascribed to the adsorbed HCHO
DOI: 10.1039/C6CP08223H
no observable deactivation of the catalyst during five repeated accumulated on the catalyst surface. The peak of linear adsorbed
cycles in terms of HCHO removal and CO2 generation. This suggests CO was also observed at 2088 cm–1 58,59
.
that the catalyst has efficient and stable activity for decomposing
The peaks in the range of 1800 and 1100 cm−1 were more
HCHO at ambient condition, which is of great importance especially closely examined (Fig. 8b). The peak at 1635 cm−1 further confirms
in practical applications. Moreover, it is worth noting that the the formation of H2O on the surface of the catalyst, and a sharp
decrease of CO2 concentration in the first cycle (Fig. 7) was mainly peak at 1598 cm−1 is assigned to νas(COO), further implying the
due to the CO2 adsorption onto the Al2O3 molecular sieves, which existence of formate species.32,60 Moreover, the peaks assigned to
would soon reach equilibrium because of its limited absorption DOM species [1485 cm−1 for δ(CH2) and 1146 cm−1 for ν(CO)] and
capacity.
formate species [1443 and 1428 cm−1 for β(CH), 1265 and 1197 cm−1
for ν(COO)] appeared and became dominant with increasing
reaction time, thus indicating that formate and DOM species are
major intermediates during HCHO decomposition over the
catalyst.58
Fig. 7 Changes in HCHO concentration (a) and ΔCO2 (b) of the Pt-AO1 sample
in recycle tests (ΔCO2 is the difference between CO2 concentrations at t
reaction time and initial time).
Mechanism of HCHO decomposition
Fig. 8 DRIFTS study of HCHO decomposition on Pt-AO1 at room temperature
in the 4000–1100 cm–1 region (a) and magnified 1800–1100 cm–1 region (b).
DRIFTS analysis was performed to investigate the HCHO oxidation
mechanism over the Pt-AO1 catalyst. Fig. 8 exhibits the changes in
the spectra of Pt-AO1 catalystin the mixed gas flow of HCHO and O2
at room temperature. The negative peak at 3735 cm−1 observed in
Fig. 8a can be assigned to the hydroxyl group on the surface of
catalysts.29,32 This declining peak indicates that the hydroxyl group
is consumed in HCHO decomposition,32 while the increasing broad
peak in the range of 3000 and 3500 cm−1 suggests the formation of
surface water.57 Meanwhile, the peaks at 2978, 2880 and 2786 cm−1
could be attributed to ν(CH), νs(CH) of formate species58 and
Therefore, based on the DRIFTS results, a possible pathway of
hydroxyl-consuming HCHO decomposition over Pt-AO1 can be
proposed. Firstly, gaseous HCHO is adsorbed and reacts with
surface OH on the catalyst surface forming DOM. Subsequently, O2
molecules dissociate on the Pt NPs and split into active oxygen
atoms,61 while the generated DOM is converted into formate
species.24 Afterwards, formate species is further oxidized into
adsorbed CO and H2O.30 Finally, CO reacts with nearby active
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Scheme
1 Proposed mechanism of HCHO decomposition and OH
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oxygen atoms to form adsorbed CO2, which is quickly desorbed
from catalyst surface.
regeneration over Pt-AO1sample.
DOI: 10.1039/C6CP08223H
Regeneration of surface hydroxyl group
Conclusions
It should be noted that surface OH is continuously consumed in the The Pt-deposited Al2O3 molecular sieves were prepared through an
above mechanism, while no obvious deactivation of Pt-AO1 was impregnation method. As-prepared catalysts exhibited excellent
observed in catalytic stability tests (Fig. 7). In this case, the
examined Pt-AO1 in the DRIFTS test was maintained in DRIFTS cell
reactor for 2 h without injecting the flow of HCHO and O2, and then
mixed gas was injected to start the second DRIFTS test without
subtracting background spectrum. The corresponding spectra are
catalytic activity and stability for HCHO decomposition. The
enhanced catalytic performance towards HCHO oxidation is
attributed to the large specific surface area, mesopore structure
and well-dispersed Pt NPs improved by the treatment of acid
solution. Besides, the DRIFTS results indicate that DOM and formate
shown in Fig. 9. It can be seen that the surface OH significantly species as intermediates are formed through the reaction between
decreased during the first round of HCHO oxidation for 50 min.
However, the amount of OH improved at the start (0 min) of the
2nd test compared with that of the end of the 1st test (i.e. at 50
min). Besides, the accumulated H2O decreased during the 2-h pause,
indicating that surface OH is probably regenerated from the
HCHO and surface hydroxyls. Then, the intermediates are further
oxidized into CO2 and H2O by active oxygen atoms on Pt-Al 2O3
catalysts at room temperature. Meanwhile, the consumed surface
hydroxyls can be regenerated from the H2O on catalyst surface,
preventing the deactivation of catalysts. In this study, the Pt-Al 2O3
produced H2O on the surface of the catalyst.62−64 Therefore, the molecular sieves with efficient HCHO decomposition activity at
mechanism of HCHO decomposition and OH regeneration over Pt- room temperature can be easilyused in practical application owing
AO1 can be proposed and illustrated in Scheme 1.
to its good portability and recyclability, which also provides new
insights into designing novel catalysts forindoorair purification.
Acknowledgements
This work was supported by the 973 program (2013CB632402),
NSFC (51320105001, 51372190, 21573170 and 21433007), NSFHB
(No. 2015CFA001), Self-determined and Innovative Research Funds
of SKLWUT (2015-ZD-1) and Fundamental Research Funds for the
Central Universities (WUT: 2015-III-034).
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View Article Online
DOI: 10.1039/C6CP08223H
Al2O3 molecular sieve supported Pt was prepared for
catalytic formaldehyde oxidation at room temperature.
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