Green Catalytic Degradation of Ethyl Acetate Incurredbystrong Interactionbetween Pdo And

Supporting Information

Green catalytic degradation of ethyl acetate incurredbystrong interactionbetween PdO and Ce0.5Co0.5 supportatlowtemperature

Sadia Akram1,2⊥,Lan Chen1⊥,Qi Wang1, Zhang Xiaorui1,2, Ning Han3, Genli Shen1, Zhen Wang1* and Guanglu Ge1*

1CAS Key Laboratory of Standardization and Measurement for Nanotechnology, and CAS Center for Excellence in Nanoscience, National Centre for Nanoscience and Technology, No.11 ZhongguancunBeiyitiao Beijing 100190, China;

2University of Chinese Academy of Science, No. 19A Yuquan Road, Beijing 100049, China;

3 State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.

Fig. S1. Enlarged zone XRD patterns of pure CeO2, Ce0.5Co0.5 and Pd Ce0.5Co0.5.

Fig. S2. TEM micrograph of Ce0.5Co0.5.

Fig. S3. EDX spectra of PdO/Ce0.5Co0.5.

Fig. S4.Thermogravimetric analysis profile of PdO/Ce0.5Co0.5.

Fig. S5.TPR spectra of pure, Ce0.5Co0.5 and Pd/Ce0.5Co0.5.

By using following equation, the % contents of Ce3+has been calculated in the support (Ce0.5Co0.5).

(1)

is the percentage content of Ce3+, A is the integrate area of characteristic peak in the XPS pattern, S is sensitivity factors (S=7.399).

Surface acidic and basic properties

Generally the adsorption of the reactants happen on the support and the noble metal do not take part in the adsorption but in the dissociation of the oxygen species present in the feed stream, so to investigate the nature of surface of the catalyst support is significant. The acidity and basicity index of pure as well as support (Ce0.5Co0.5) is evaluated via ammonia and carbon dioxide TPD respectively (Fig. S6, S7). The index value per gram of dry sample is given in Table 1. It shows that Ce0.5Co0.5 is more acidic in nature than pure CeO2 and Co3O4.

Fig. S6.TPD spectra of NH3 for acidity of CeO2, Co3O4 and Ce0.5Co0.5 catalyst.

Fig. S7.TPD spectra of CO2 for basicity of CeO2, Co3O4 and Ce0.5Co0.5 catalyst.

The acidic nature of catalyst makes it more prone towards the adsorption of ethyl acetate (EA) molecules. On the surface of the composite oxide catalyst, gaseous species of EA are thought to be adsorbed on the electron deficient (Lewis acid) sites (Fig. S8). This adsorption accelerates the activation of EA which further proceeds towards the oxidation. The main CO2 desorption peaks for the CeO2 containing catalysts occurs in the range of 50-200 ˚C indicating that the catalyzed product, CO2 can be readily desorbed and removed from the catalyst surfaces under the experimental conditions. As a result, the better EA adsorption caused by Ce0.5Co0.5 materials can be ascribed to its higher affinity to acidic sites on the catalyst, where a higher acidity contributes to a faster EA decomposition while a higher basicity results in a faster release of the product, CO2.

Sr. Number / Samples / Total Acidity (mmol/g) / Total Basicity (mmol/g)
1 / CeO2 / 0.22145 / 0.32014
2 / Co3O4 / 0.06810 / 0.03518
3 / Ce0.5Co0.5 / 0.44988 / 0.29729

Table S1Total acidity and basicity of CeO2, Co3O4 and Ce0.5Co0.5 determined by NH3-TPD and CO2-TPD.

Fig. S8.Adsorption of ethyl acetate molecule on acidic active sites.

Table S2Binding energy (eV) values and Atomic Ratios (%) ofCe 3d, Co2p and O 1s spectra of Ce0.5Co0.5 andPdO/ Ce0.5Co0.5.

Samples / Ce 3d / Co 2p / O1s
Binding Energy
(eV) / Atomic Ratio (%) / Binding Energy
(eV) / Atomic Ratio (%) / Binding Energy
(eV) / Atomic Ratio (%)
Ce0.5Co0.5 / 879, 881, 885.5, 888, 897, 898, 900, 903.9, 907, 916.1 / 14.0 / 779.2, 794.4 / 4.0 / 529.0, 531, 533.5 / 55.0
PdO/Ce0.5Co0.5 / 879, 881, 885.5, 888, 897, 898, 900, 903.9, 907, 916.1 / 9.8 / 779.2, 794.4 / 3.2 / 529.0, 531, 533 / 32.8

Fig.S9. X-ray photoelectron spectra for Ce 3d (a), Co 2p (b), O 1s (c) of Ce0.5Co0.5and PdO/ Ce0.5Co0.5 catalysts.