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Constructing Pd/CeO2/C to Achieve Highly Leaching-resistance and Active for Catalytic Wet Air Oxidation of Aqueous Amide Jile Fu, Qingqing Yue, Haozhe Guo, Changjian Ma, Yaoyao Wen, Hua Zhang, Nuowei Zhang, Yanping Zheng, Jinbao Zheng, and Bing-Hui Chen ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.8b00962 • Publication Date (Web): 25 Apr 2018 Downloaded from http://pubs.acs.org on April 25, 2018
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Constructing Pd/CeO2/C to Achieve Highly Leachingeaching-resistance and Active for Catalytic Wet Air Oxidation of Aqueous Amide Jile Fu, Qingqing Yue, Haozhe Guo, Changjian Ma, Yaoyao Wen, Hua Zhang, Nuowei Zhang,* Yanping Zheng, Jinbao Zheng, and Bing-Hui Chen* Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of AlcoholsEthers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
Supporting Information Placeholder ABSTRACT: Strong metal-support interaction involving the electron and oxygen transfer in Pd/C (no leaching but less active) and Pd/CeO2 (active but leaching) catalysts determines their catalytic performance in the catalytic wet air oxidation of amide. To control these two types of interaction, the triple-layer structure of Pd/CeO2/C, where Pd is predominantly located on CeO2 and CeO2 on C support, was designed and prepared. As a result, the electrons could be transferred from carbon to Pd via CeO2 for excellent leaching-resistance, while oxygen was transferred from CeO2 to Pd for high oxidation activity. Besides, both of these two types of interaction could be easily adjusted by changing the amount of CeO2. Keywords: catalytic wet air oxidation, metal-support interaction, triple-layer structure, resistance to metal leaching, Pd, CeO2 Introduction The so-called ‘strong metal-support interaction’ (SMSI) has been well known since Tauster1,2 reported the dramatic changes of the H2 and CO chemisorption on Pt or other Group VIII metals which are dispersed on TiO2 in the 1970s. The chemisorption of CO and H2 was largely suppressed after the catalysts were reduced by H2 at elevated temperature. This phenomenon was correlated with the SMSI between the reduced cations of metal oxide and adjacent nanoparticles. After that, a large number of studies have focused on the investigations of local environment of metal-metal oxide, especially the perimeter interface sites.3-10 Recently, Illas and coworkers11 identified two types of interactions on well-defined models of Pt-CeO2 using computational method: electron transfer from Pt to CeO2 and activated oxygen transfer from CeO2 to Pt (oxygen reverse spillover). These two mechanisms coexist in two different channels and have been detected by resonant photoelectron spectroscopy. On one hand, the electron transfer is purely electronic effect, which is then suggested to be electronic metal–support interaction (EMSI) by Campbell.12 Its catalytic enhancement was soon verified in the water-gas shift (WGS) reaction, leading to 20-fold increase in rate.13 Similar phenomenon has also been observed in Au nanoparticles on ZnO nanorods and Pt nanoparticles on vacancy-abundant hexagonal boron nitride nanosheets.14,15 Lykhach and co-workers16 quantified charge transfer between Pt nanoparticles and ceria support by combing experiments and density functional calculations, further confirming the electronic metal– support interaction. On the other hand, the second channel involv-
ing the transport of activated oxygen is only operative on nanostructured ceria in intimate contact with Pt.11 Happel and coworkers identified the oxygen reverse spillover from support (ceria) to Pt through vibrational spectroscopy of adsorbed CO.17 Furthermore, oxygen diffusion in the interface of Pt and Ce2Zr2Ox was directly imaged by scanning X-ray absorption fine structure (XAFS) using hard X-ray nanobeams.18 It is clear that this new type of SMSI enhances the activity of noble metal in CO oxidation or WGS. However, in some other practical reactions, different properties of metal nanoparticles are needed based on the reaction mechanism. For instance, the group of Zheng 19 reported the effect of electronic change of Pt on the partial hydrogenation of nitroaromatics. Pt nanoparticles were made electron-rich through the electron donation from the coated ethylenediamine for the high selectivity of N-hydroxylanilines. This reverse electron transfer (Pt as electron acceptor) is openminded and inspiring for us to make the SMSI more flexible and generally applicable. Herein, we reported a new idea to tune the electron transfer and oxygen transfer between metal and support by constructing a triple-layer catalyst which presents unexpectedly good performance in the catalytic wet air oxidation (CWAO) of N, N-dimethylformamide (DMF). DMF is one of the most common chemical pollutants in industrial wastewater.20 CWAO shows great potentials with its high efficiency and adaptability in such wastewater treatment.21 However, according to the results of Besson,22 dimethylamine (DMA) and methylamine (MA) as intermediates in the DMF decomposition can induce serious leaching (20%-100%) since these compounds possess lone pair electrons on their nitrogen atom which easily enter the unoccupied orbital of metals and convert them to be soluble material. But what is even worse is that, as indicated previously, the widely used metal-oxide supports (i.e. ceria) always work as electron acceptor, making the complexation even easier. Our results indicated that the C support can give electrons to Pt and Cu metal to compensate the electron loss,23,24 but carbon has no ability to activate and transfer oxygen to metal nanoparticles. Thus, what if we combine carbon and CeO2 to take the advantage of both? In this work, a triple-layer Pd/CeO2/C catalyst with high leaching-resistance and activity for CWAO of DMF has been designed and prepared, where C support can be the electron donor to reverse the electron transfer on the purpose of resistance
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Figure 1. (a) Surface charge of support at different pH values. PZC is the pH at which the support is neutral. (b) Zeta-potential of CeO2 and C at different pH values. (c) UV-vis absorption spectra of NH3, H2PdCl4, and Pd(NH3)4Cl2 solution. (d) UV-vis adsorption spectra of the mixture of H2PdCl4 and NH3 solution. (e) Mechanism of the synthesis of Pd/CeO2/C and Pd-CeO2/C. leaching while CeO2 will enhance the oxidizing ability of Pd metal due to its oxygen storage and transfer capacity. For comparison, the Pd-CeO2/C catalyst was also prepared, where most of Pd and CeO2 were separately supported on carbon. Catalysts preparation The CeO2/C was prepared by the impregnation method with calcination (supporting information) to ensure the interaction between C and CeO2. Fornasiero et al25 used the magnetic CNTs as nanocatalysts supports, which showed that the C functionalization may affect the interaction between C and ceria precursor. The separation of CeO2 and C is possible to occur. In order to confirm that all the CeO2 particles were supported on C, the statistical analysis of TEM images was performed (figure S1). The results proved that only CeO2/C could be observed. As is shown in work of Regalbuto,26 there is strong electrostatic adsorption between the metal complex and the support in solutions. For common supports that were placed in solutions, its surface charge would change with the pH of the solution (figure 1a). As is shown in figure 1b, the zeta-potential of C and CeO2 is obtained when they were dispersed in water at different pH values. At acidic condition, both C and CeO2 are positively charged. With the increase of pH, the zeta-potential of C decreases slowly and stays almost neutral at basic condition. However, zeta-potential of CeO2 goes down rapidly and become negative charged as the pH reaches 5. Meanwhile, the charge of Pd complex could also be changed with different coordination. Figure 1c shows the UV-vis adsorption spectra of different Pd complex ([PdCl4]2- and [Pd(NH3)4]2+). In the solution of H2PdCl4, Pd complex is negatively charged. If a certain amount of ammonia was added, the [PdCl4]2- would be converted to be [Pd(NH3)4]2+ (figure 1d) which is positively charged.
Therefore, the two kinds of catalysts (Pd/CeO2/C and PdCeO2/C) were synthesized based on the electronic adsorption between metal complex and support. Figure 1e illustrates the mechanism of the synthesis. Pd/CeO2/C is synthesized at basic condition. Ammonia is used to increase the pH of the solution and convert [PdCl4]2- to [Pd(NH3)4]2+. As CeO2 is negatively charged and C is almost neutral, Pd complex (positively charged) would selectively deposit on the surface of CeO2. The addition of hydrazine could accelerate the deposition of Pd nanoparticles. On the other hand, Pd-CeO2/C was synthesized at acidic condition with [PdCl4]2-. Both C and CeO2 are able to adsorb Pd complex.
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Scheme 1. Schematic illustration of constructing the triple-layer Pd/CeO2/C catalyst. Nevertheless, as the specific area of C (1372 m2/g, table S1) is high and the CeO2 loading is only 20%, most of the Pd would deposit on C. Properties and performance of catalysts We firstly investigated the effect of supports on the catalytic performance of Pd-based catalysts for CWAO of DMF and the results are shown in Table 1. Considering the production of intermediate compounds (i.e. MA and DMA) is the main reason for metal leaching, the MA oxidation was also performed to test the leaching resistance. Pd/C catalyst showed a remarkable leaching resistance ability, no metal being washed out during the CWAO process of MA, and not to the DMF as well definitely. In contrast, 50%, 70% and 90% of Pd metal was dissolved during the MA oxidation over Pd/CeO2, Pd/TiO2 and Pd/Al2O3, respectively. As for DMF oxidation over the above three oxide-supported Pd catalysts, the amount of Pd dissolved in the solution was lower than that of MA, but still greater than 10%. As it is mentioned above, the metal leaching is incurred by the lone pair electron in N atom of amine. Therefore, the outstanding metal leaching resistance of Pd/C should be related to the modified electronic property of Pd. This was confirmed by the quasi-in situ XPS results shown in figure 2A (Pd/C and Pd/CeO2) and figure S2 (Pd/TiO2 and Pd/Al2O3). Detailed information of the valence distribution is shown in Table S2. It can be seen that Pd/C contained over 90% Pd0, which was consistent with reported results.27,28 As for Pd on metal oxide (CeO2, TiO2 and Al2O3), much less Pd0 was detected (in the range of 44-63%) and even Pd4+ was observed which was not found in Pd/C. These results confirm the electron transfer from Pd to support. Carbon transfers electron to noble metal23 while oxides accept electron from noble metal.11 The obtained high electron density for Pd on carbon leads to its resistance to lone pair electron of N atom, which avoids Pd metal from leaching. However, as for Pd supported on CeO2, its low electron density promotes the coordination of Pd with the intermediate compounds (MA and DMA), which results in serious metal leaching.
Table 1. Catalytic wet air oxidation of DMF and MA.
Catalyst
TOC Conversion (%) a
Pd Leached (%) a
TOC Conversion (%) b
Pd Leached (%) b
Pd/C
30
0
67
0
Pd/CeO2
87
10
72
45
Pd/TiO2
75
15
54
70
Pd/Al2O3
66
11
30
90
Pd/20CeO2/C
80
0
88
0
Pd-20CeO2/C
46
0
75
0
Pd/10CeO2/C
63
0
80
0
Pd/30CeO2/C
88
3.5
86
17
Pd/50CeO2/C
86
10
87
43
a: aqueous DMF solution=15 ml, DMF=2500 ppm, b: MA=1000 ppm, aqueous MA solution=15 ml. Pd/C presented a very poor activity for DMF oxidation, only 30% “total organic carbon” (TOC) conversion while Pd/CeO2 can remove about 85% TOC at the same condition. The superior performance of CeO2 in oxidation process has been reported many times, due to its high oxygen storage and excellent interaction with noble metals.29-33 Figure 2B compares the CO-TPR of Pd/C and Pd/CeO2 (CO2 signal). For Pd/CeO2, three reduction peaks were observed at temperatures lower than 500 oC, attributing to the reduction of surface Pd-O-Ce, dispersed PdO and crystal PdO,
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respectively.34-36 As for Pd/C, only a very little peak was observed at low-temperature zone. Clearly, CeO2 can increase the oxidizing ability of Pd through oxygen transfer.13 Taking advantage of both CeO2 and carbon, a novel Pd/CeO2/C catalyst with triple-layer structure (as shown in Scheme 1) was designed and prepared. In this special catalyst, oxygen transfer is ensured through the direct interaction between Pd and CeO2, just like Pd/CeO2. As shown in figure 2B, Pd/CeO2/C catalyst presented a very similar CO-TPR pattern with Pd/CeO2. Simultaneously, the triple-layer structure also ensured the electron be transferred from carbon to CeO2 and then to Pd. The XPS results (figure 2A and Table S1) indicated the percentage of Pd0 (87%) of Pd/CeO2/C is much higher than that of Pd/CeO2 (59%), and slightly lower than that of Pd/C (94%), although Pd were located on CeO2. Besides, no Pd4+ was found in Pd/20CeO2/C. During this process, CeO2 was reduced due to the electron transfer from the support (proved by the XPS results, shown in Figure S3).
and line-scan EDX analysis of Pd/20CeO2/C (CeO2 loading is 20 wt%). Both agglomerated CeO2 and Pd nanoparticles appear brighter than carbon and the resolution between CeO2 and Pd is very poor. It is hard to distinguish them in the STEM image. However, the line-scan EDX analysis (figure 3B) indicated Pd tended to grow on the CeO2 rich surface, where the intensity of Pd and Ce trace had almost the same evolution trend and the positions of their peaks were almost identical. The structure of Pd on CeO2 was further confirmed by the results of the elemental mapping, as shown in Figure 3D-3H, where Pd signals matched very well with the Ce signals. The interplanar spacing d is measured as 0.2249 nm and 0.3053 nm in figure 3J, which match Pd {111} and CeO2 {111}, respectively. The structure of Pd on CeO2 made Pd/20CeO2/C have a very similar Pd dispersion with Pd/CeO2. The corresponding TEM results of Pd-20CeO2/C are shown in figure S4, which clearly indicates that most of the Pd nanoparticles are located on C instead of CeO2.
Figure 2. The comparison between (a) Pd/C, (b) Pd/20CeO2/C and (c) Pd/CeO2. (A) Quasi-in situ XPS spectra, (B) CO2 signal of CO-TPR-MASS. As it is hard to distinguish the Pd from CeO2 in the TEM image, the dispersion of Pd was measured by the CO-chemisorption. The results are shown in table 2, which shows that the location of Pd has strong influence on the their particle sizes. The Pd nanoparticles supported C (8.2% for Pd/C and 10.4% for Pd-20CeO2/C) obtain much better dispersion than that of Pd on CeO2 (3.1% for Pd/CeO2 and 3.0% for Pd/20CeO2/C). It probably results from the different surface area of different supports. The surface area of C (BP000) is 1372 m2/g, while the surface area of CeO2 is only 86 m2/g. (table S1)
Table 2. Metal dispersions of Pd in different catalysts. Catalyst Pd/C Pd/CeO2 Pd/TiO2 Pd/Al2O3 Pd/20CeO2/C Pd-20CeO2/C
Metal dispersion 8.2% 3.1% 3.1% 3.1% 3.0% 10.4%
Particles size (nm) 13.7 35.6 36.1 36.5 37.0 10.8
Metallic surface area (m2/g) 36.4 14.0 13.8 13.7 13.5 46.2
Figure 3. (A) HADDF-STEM image of Pd/20CeO2/C with the trace of line scan. (B) line-scan analysis of Pd/20CeO2/C. (C) HADDF-STEM image of Pd/20CeO2/C for the elemental mapping. (D)-(F) the elemental mapping results of Pd, Ce and C. (G) Overlayer of Ce and Pd. (H) Overlayer of Ce, Pd and C. (I) FFT pattens. (J) HRTEM of Pd and CeO2 in Pd/20CeO2/C. (K) TEM image of Pd/20CeO2/C.
Structure-performance Correlations Figure 3A and 3B present the high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM)
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Figure 4. H2 signal of the water-gas shift reaction with the surface hydroxide of different materials. The peak at 425 oC is the proof of PdCeO2 interactions which can be observed both in Pd/CeO2 and Pd/20CeO2/C. To further identify the structures of the as-synthesis catalysts, the CO-TPR-MASS (H2 signal) of 3Pd/C, Pd/CeO2, CeO2, Pd/20CeO2/C and 20CeO2/C were carried out as illustrated in Figure 4. The H2 was produced from the WGS reaction between CO and surface hydroxide.37 For CeO2, a H2 signal peak was observed at 500 oC, while a new peak was at 425 oC for Pd/CeO2 since Pd could promote the WGS reaction. However, if Pd is supported on carbon, negligible signal of H2 could be observed, indicating that WGS reaction can hardly occur on the surface of C or Pd/C. The peak at 530 oC for 20CeO2/C corresponds to peak at 500 o C for CeO2, as WGS reaction could not proceed on the surface of C. Pd/20CeO2/C presented a similar H2 signal pattern with Pd/CeO2, indicating that Pd was mainly deposited on the CeO2 surface, which further approved the fact that Pd/20CeO2/C possessed a triple-layer structure. On the other hand, the H2 signal for Pd-20CeO2/C presnted a similar pattern to 20CeO2/C and no enhancement on WGS reaction was observed. (figure S5) Therefore, it is reasonable to infer that most of Pd and CeO2 were separately supported on carbon. This was consistent with the linescan EDX analysis and elemental mapping results, as shown in Figure S4.
Table 3. Catalytic wet air oxidation of DMF and MA.
Catalyst
TOC conversion normalized by the surface area of Pd (%/m2 g-1) a
TOC conversion normalized by the surface area of Pd (%/m2 g-1) b
Pd/C
0.8
1.8
Pd/CeO2
6.2
5.1
Pd/TiO2
5.4
3.9
Pd/Al2O3
4.8
2.2
Pd/20CeO2/C
5.9
6.5
Pd-20CeO2/C
1.0
1.6
a: aqueous DMF solution=15 ml, DMF=2500 ppm, b: MA=1000 ppm, aqueous MA solution=15 ml.
The catalytic performance of Pd/20CeO2/C and Pd-20CeO2/C was investigated comparatively and the results are also shown in Table 1. As expected, triple-layer structure ensured Pd/20CeO2/C to possess both high activity and excellent ability to prevent Pd metal from leaching. The TOC conversion over Pd/20CeO2/C was up to 80%, comparable with that of Pd/CeO2, while no Pd leaching was observed which occurred over Pd/CeO2. For Pd20CeO2/C catalyst, CeO2 modification did not lead to a significant enhancement on activity as the TOC conversion was only 46%, much lower than that of Pd/20CeO2/C, since Pd and CeO2 were separately supported and oxygen cannot effectively be transported to Pd from CeO2 (Scheme 1). Table 3 presents the TOC conversions that are normalized by the surface areas of Pd. As the surface areas of Pd that located on C are higher than that of Pd on CeO2, the normalization makes the activity of Pd on C (Pd/C and Pd-20CeO2/C) much lower than that of Pd on CeO2 (Pd/CeO2 and Pd/20CeO2/C). These results further confirms that Pd-CeO2 interactions is essential for the activity of Pd based catalysts in the catalytic wet air oxidation of DMF. The re-usability of Pd/20CeO2/C was also studied and the results are shown in Figure S6, showing that Pd/20CeO2/C exhibited a very stable catalytic performance. No deactivation and metal leaching was observed and the conversion of TOC could be maintained at a level higher than 75% in the 5 consecutive runs. The stable activity proved that Pd size did not change after reaction, as the activity of Pd/20CeO2/C is sensitive to the Pd size. We investigated the effect of Pd size on the activity of Pd/20CeO2/C, which showed that the TOC conversion would drop dramatically if the Pd size was further increased. The effect of CeO2 loading on the catalytic performance of Pd/CeO2/C was further investigated and the results were shown in Table 1. The CeO2 loading strongly affected both the activity and the resistance to Pd leaching of Pd/CeO2/C. Low CeO2 loading ensured high resistance to leaching but low catalytic activity. The TOC conversion was 63% for Pd/10CeO2/C, and TOC conversion was increased to 80% when CeO2 loading was increased to 20%. With further increasing CeO2 loading to 30%, TOC conversion reached a high value of 88%, but Pd leaching occurs. Although Pd/50CeO2/C presented a similar activity with Pd/30CeO2/C, serious metal leaching was observed and reached the same level as Pd/CeO2. Considering the CeO2 was located between C support and Pd active metal, the CeO2 property will strongly affected the Pd fea-
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tures. At high CeO2 loading, the CeO2 deposited on C support will exhibit similar physicochemical properties with the bulk CeO2, confirmed by the XPS results of 50CeO2/C (shown in figure S7) which was very similar with that of pure CeO2. Therefore, with the increase of CeO2 loading, the electron will be transformed from Pd to CeO2 while oxygen from CeO2 to Pd. This was approved by the XPS results of a series of Pd/CeO2/C catalysts. As shown in Table S1, Pd0 fraction was decreased from 91 to 61% with CeO2 loading increasing from 10 to 50%. The enhanced oxygen transformation from CeO2 to Pd was mainly responsible for the increasing activity while the depressed electron transformation from C to Pd was mainly for the more severe leaching due to the low electron density. Conclusions In summary, the triple-layer structure of Pd/CeO2/C guaranteed the proper control of electron transfer and oxygen transfer based on the reaction mechanism. With 20 wt% CeO2 loading, oxygen was transferred from CeO2 to Pd, and electron was transferred from C to Pd via CeO2. Thus, high resistance to metal leaching with excellent catalytic activity for CWAO of aqueous amide was achieved. Besides, both of these two types of interaction can be modified through changing the loading of CeO2.
Supporting Information Experimental procedures, synthesis of support and catalysts, details on the quasi-in situ XPS, TEM, CO-TPR and metal dispersion.
AUTHOR INFORMATION Corresponding Author *
[email protected] *
[email protected] ACKNOWLEDGMENT The authors would like to thank the financial supports from the Natural Science Foundation of China (21673187, 21336009) and National Key Technology Support Program of China (2014BAC10B01). The supports by the Natural Science Foundation of Fujian Province of China (2015J05031) is also acknowledged.
REFERENCES (1) Tauster, S. J.; Fung, S. C.; Garten, R. L. Strong Metal-support Interactions. Group 8 Noble Metals Supported on TiO2. J. Am. Chem. Soc. 1978, 100, 170-175. (2) Tauster, S. J.; Fung, S. C.; Baker, R. T. K.; Horsley, J. A. Strong Interactions in Supported-metal Catalysts. Science 1981, 211, 1121-1125. (3) Remediakis, I. N.; Lopez, N.; Nørskov, J. K. CO Oxidation on Rutilesupported Au Nanoparticles. Angew. Chem., Int. Ed. 2005, 44, 1824-1826. (4) Cargnello, M.; Doan-Nguyen, V. V. T.; Gordon, T. R.; Diaz, R. E.; Stach, E. A.; Gorte, R. J.; Fornasiero, P.; Murray, C. B. Control of Metal Nanocrystal Size Reveals Metal-support Interface Role for Ceria Catalysts. Science 2013. (5) Fujitani, T.; Nakamura, I. Mechanism and Active Sites of the Oxidation of CO Over Au/TiO2. Angew. Chem., Int. Ed. 2011, 50, 10144-10147. (6) Widmann, D.; Behm, R. J. Active Oxygen on a Au/TiO2 Catalyst: Formation, Stability, and CO Oxidation Activity. Angew. Chem., Int. Ed. 2011, 50, 10241-10245. (7) Maeda, Y.; Iizuka, Y.; Kohyama, M. Generation of Oxygen Vacancies at a Au/TiO2 Perimeter Interface During CO Oxidation Detected by in Situ Electrical Conductance Measurement. J. Am. Chem. Soc. 2013, 135, 906909. (8) Widmann, D.; Behm, R. J. Activation of Molecular Oxygen and the Nature of the Active Oxygen Species for CO Oxidation on Oxide Supported Au Catalysts. Acc. Chem. Res. 2014, 47, 740-749.
(9) Zhou, Z.; Kooi, S.; Flytzani-Stephanopoulos, M.; Saltsburg, H. The Role of the Interface in CO Oxidation on Au/CeO2 Multilayer Nanotowers. Adv. Funct. Mater. 2008, 18, 2801-2807. (10) Liu, H.; Kozlov, A. I.; Kozlova, A. P.; Shido, T.; Asakura, K.; Iwasawa, Y. Active Oxygen Species and Mechanism for Low-temperature CO Oxidation Reaction on a TiO2-supported Au Catalyst Prepared from Au(PPh3)(NO3) and As-precipitated Titanium Hydroxide J. Cata. 1999, 185, 252-264. (11) Vayssilov, G. N.; Lykhach, Y.; Migani, A.; Staudt, T.; Petrova, G. P.; Tsud, N.; Skála, T.; Bruix, A.; Illas, F.; Prince, K. C.; Matolı´n, V. r.; Neyman, K. M.; Libuda, J. Support Nanostructure Boosts Oxygen Transfer to Catalytically Active Platinum Nanoparticles. Nat. Mater. 2011, 10, 310-315. (12) Campbell, C. T. Catalyst–support Interactions: Electronic Perturbations. Nat. Chem. 2012, 4, 597-598. (13) Bruix, A.; Rodriguez, J. A.; Ramirez, P. J.; Senanayake, S. D.; Evans, J.; Park, J. B.; Stacchiola, D.; Liu, P.; Hrbek, J.; Illas, F. A New Type of Strong Metal–support Interaction and the Production of H2 Through the Transformation of Water on Pt/CeO2 (111) and Pt/CeOx/TiO2 (110) Catalysts. J. Am. Chem. Soc. 2012, 134, 8968-8974. (14) Liu, X.; Liu, M.-H.; Luo, Y.-C.; Mou, C.-Y.; Lin, S. D.; Cheng, H.; Chen, J.-M.; Lee, J.-F.; Lin, T.-S. Strong Metal–support Interactions Between Gold Nanoparticles and ZnO Nanorods in CO Oxidation. J. Am. Chem. Soc. 2012, 134, 10251-10258. (15) Zhu, W.; Wu, Z.; Foo, G. S.; Gao, X.; Zhou, M.; Liu, B.; Veith, G. M.; Wu, P. Taming Interfacial Electronic Properties of Platinum Nanoparticles on Vacancy-abundant Boron Nitride Nanosheets for Enhanced Catalysis. Nat. Commun. 2017, 8, 15291. (16) Lykhach, Y.; Kozlov, S. M.; Skala, T.; Tovt, A.; Stetsovych, V.; Tsud, N.; Dvorak, F.; Johanek, V.; Neitzel, A.; Myslivecek, J.; Fabris, S.; Matolin, V.; Neyman, K. M.; Libuda, J. Counting Electrons on Supported Nanoparticles. Nat. Mater. 2016, 15, 284-288. (17) Happel, M.; Myslivecek, J.; Johanek, V.; Dvorak, F.; Stetsovych, O.; Lykhach, Y.; Matolin, V.; Libuda, J. Adsorption Sites, Metal-support Interactions, and Oxygen Spillover Identified by Vibrational Spectroscopy of Adsorbed CO: A Model Study on Pt/Ceria Catalysts. J. Cata. 2012, 289, 118-126. (18) Matsui, H.; Ishiguro, N.; Enomoto, K.; Sekizawa, O.; Uruga, T.; Tada, M. Imaging of Oxygen Diffusion in Individual Platinum/Ce2Zr2Ox Catalyst Particles During Oxygen Storage and Release. Angew. Chem., Int. Ed. 2016, 55, 12022-12025. (19) Chen, G.; Xu, C.; Huang, X.; Ye, J.; Gu, L.; Li, G.; Tang, Z.; Wu, B.; Yang, H.; Zhao, Z.; Zhou, Z.; Fu, G.; Zheng, N. Interfacial Electronic Effects Control the Reaction Selectivity of Platinum Catalysts. Nat. Mater. 2016, 15, 564-569. (20) Chen, Y.; Li, B.; Qiu, Y.; Xu, X.; Shen, S. A Novel Chemical/Biological Combined Technique for N, N-dimethylformamide Wastewater Treatment. Environ. Technol. 2016, 37, 1088-1093. (21) Luck, F. A Review of Industrial Catalytic Wet air Oxidation Processes. Catal. Today 1996, 27, 195-202. (22) Grosjean, N.; Descorme, C.; Besson, M. Catalytic Wet Air Oxidation of N, N-dimethylformamide Aqueous Solutions: Deactivation of TiO2 and ZrO2-supported Noble Metal Catalysts. Appl. Catal., B 2010, 97, 276-283. (23) Zhang, H.; Zheng, Z.; Ma, C.; Zheng, J.; Zhang, N.; Li, Y.; Chen, B. H. Tuning Surface Properties and Catalytic Performances of Pt–Ru Bimetallic Nanoparticles by Thermal Treatment. ChemCatChem 2015, 7, 245249. (24) Fu, J.; Yang, K.; Ma, C.; Zhang, N.; Gai, H.; Zheng, J.; Chen, B. H. Bimetallic Ru–Cu as a Highly Active, Selective and Stable Catalyst for Catalytic Wet Oxidation of Aqueous Ammonia to Nitrogen. Appl. Catal., B 2016, 184, 216-222. (25) Melchionna, M.; Beltram, A.; Stopin, A.; Montini, T.; Lodge, R. W.; Khlobystov, A. N.; Bonifazi, D.; Prato, M.; Fornasiero, P. Magnetic Shepherding of Nanocatalysts Through Hierarchically-assembled Fe-filled CNTs Hybrids. Appl. Catal., B 2018, 227, 356-365 (26) Jiao, L.; Regalbuto, J. R. The Synthesis of Highly Dispersed Noble and Base Metals on Silica via Strong Electrostatic Adsorption: I. Amorphous Silica. J. Cata. 2008, 260, 329-341. (27) Miller, H. A.; Lavacchi, A.; Vizza, F.; Marelli, M.; Di Benedetto, F.; D'Acapito, F.; Paska, Y.; Page, M.; Dekel, D. R. A Pd/C-CeO2 Anode Catalyst for High-performance Platinum-free Anion Exchange Membrane Fuel Cells. Angew. Chem., Int. Ed. 2016, 128, 6108-6111. (28) Zhou, W.; Li, M.; Ding, O. L.; Chan, S. H.; Zhang, L.; Xue, Y. Pd Particle Size Effects on Oxygen Electrochemical Reduction. Int. J. Hydrogen Energy 2014, 39, 6433-6442.
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ACS Catalysis (29) Kašpar, J.; Fornasiero, P.; Graziani, M. Use of CeO2-based Oxides in the Three-way Catalysis. Catal. Today 1999, 50, 285-298. (30) Matsumoto, S. i. Recent Advances in Automobile Exhaust Catalysts. Catal. Today 2004, 90, 183-190. (31) Yao, H. C.; Yao, Y. F. Y. Ceria in Automotive Exhaust Catalysts: I. Oxygen Storage. J. Cata. 1984, 86, 254-265. (32) Gatla, S.; Aubert, D.; Agostini, G.; Mathon, O.; Pascarelli, S.; Lunkenbein, T.; Willinger, M. G.; Kaper, H. Room-temperature CO Oxidation Catalyst: Low-temperature Metal–support Interaction Between Platinum Nanoparticles and Nanosized Ceria. ACS Catal. 2016, 6, 61516155. (33) Ke, J.; Zhu, W.; Jiang, Y.; Si, R.; Wang, Y.-J.; Li, S.-C.; Jin, C.; Liu, H.; Song, W.-G.; Yan, C.-H.; Zhang, Y.-W. Strong Local Coordination Structure Effects on Subnanometer PtOx Clusters Over CeO2 Nanowires Probed by Low-temperature CO Oxidation. ACS Catal. 2015, 5, 51645173. (34) Slavinskaya, E. M.; Gulyaev, R. V.; Zadesenets, A. V.; Stonkus, O. A.; Zaikovskii, V. I.; Shubin, Y. V.; Korenev, S. V.; Boronin, A. Lowtemperature CO Oxidation by Pd/CeO2 Catalysts Synthesized Using the Coprecipitation Method. Appl. Catal., B 2015, 166, 91-103. (35) Slavinskaya, E. M.; Kardash, T. Y.; Stonkus, O. A.; Gulyaev, R. V.; Lapin, I. N.; Svetlichnyi, V. A.; Boronin, A. I. Metal–support Interaction in Pd/CeO2 Model Catalysts for CO Oxidation: From Pulsed Laser-ablated Nanoparticles to Highly Active State of the Catalyst. Catal. Sci. Technol. 2016, 6, 6650-6666. (36) Luo, M.-F.; Hou, Z.-Y.; Yuan, X.-X.; Zheng, X.-M. Characterization Study of CeO2 Supported Pd Catalyst for Low-temperature Carbon Monoxide Oxidation. Catal. Lett. 1998, 50, 205-209. (37) Zhu, H.; Qin, Z.; Shan, W.; Shen, W.; Wang, J. Pd/CeO2-TiO2 Catalyst for CO Oxidation at Low Temperature: a TPR Study With H2 and CO as Reducing Agents. J. Cata. 2004, 225, 267-277.
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