Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/MxZryOz Catalysts and Influence of CO2 and H2O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

In the present paper, the effects of metal promoters (M = Fe, Co, and Cu) in Pt/MxZryOz catalysts and the influence of CO2 and H2O on the CO oxidation activity (PROX) were investigated. To do that, characterizations of catalyst structures and surfaces were performed and reported here. The catalyst Pt/FexZryOz (PFeZ) was the most active at low temperatures among the analyzed ones. The addition of platinum caused strong interaction with the mixed oxide, affecting the structure and the surface composition, blocking basic sites, and thus preventing catalyst deactivation. Particularly, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results evidenced the formation of carboxylate and carbonate species. Besides, the addition of CO2 and H2O in the gas feed stream affected the observed CO oxidation results, showing that CO2 competes with O2 on metallic sites. Moreover, DRIFTS and temperature-programmed desorption (TPD) analyses suggested the occurrence of OH– oxidation by CO, leading to the formation of highly reactive compounds that can be easily oxidized.


S7 -Calculation of the surface metallic area and dispersion
To calculate the metallic area, the following expression was used: where [L] is the maximum site density, or the number of surface metal atoms per m 2 .For platinum, the value of [L] is equal to 0.96x10 19 atoms/m 2 .N s is the number of surface sites; that is, the number of chemically adsorbed molecules.Considering the metal content, we have: The dispersion was calculated in accordance with the following equation: where D is the dispersion and Nt is the total number of atoms, given by the following equation: where NA is the Avogadro number, y is the fraction of the supported metal, mcat is the catalyst mass and M is the atomic mass of the metal considered.

Turnover Frequency (TOF)
The turnover frequency (TOF) was formulated as the intrinsic activity of the site,

Table Captions
Table S1 -Nomenclature and chemical composition of the catalyst and support.
Table S3 -The superficial composition from EDS analyses.
Table S4 -Quantitative desorption analyses of CO 2 of the mixed oxide support and the catalyst.
Table S5 -XPS spectral values of Platinum.
Table S6 -TPO of the FeZ and PFeZ catalyst after reaction.

Figure S6 -Figure S7 -
Figure S6 -TPSR profiles in the presence or not of CO 2 and H 2 O.

Figure S8 -
Figure S8 -Desorption profiles of CO 2 for the mixed oxide (FZ) and the catalyst (PFeZ).

Figure S1 -
Figure S1 -Isotherms of FZ and CuZ samples and of the catalysts.

Figure S2 -
Figure S2-CO 2 desorption profile of support and catalyst after CO adsorption.

Figure S4 -
Figure S4 -CO DRIFTS spectra collected in closed chamber with CO/He 1:99 mol% feed for the FeZ sample-(B) CO DRIFTS spectra collected in closed chamber with CO/He 1:99 mol% feed for the PFeZ sample.

Figure S5 -
Figure S5 -Selectivity of CO 2 of mixed oxides and catalysts for the Prox reaction.

Figure S6 -
Figure S6-TPSR profiles in the presence or not of CO 2 and H 2 O.

Figure S7 -
Figure S7 -TPO profile of FZ after TPRe with water.

Figure S8 -
Figure S8 -Desorption profiles of CO 2 for the mixed oxide (FZ) and the catalyst (PFeZ).

Table S2 -
Nomenclature and chemical composition of the catalyst and support.TPR of hydrogen consumption results.

Table S3 -
Superficial composition from EDS analyses.

Table S4 -
Quantitative desorption analyses of CO 2 of the mixed oxide support and the catalyst.

Table S5 -
XPS spectral values of Platinum.

Table S6 -
TPO of FeZ and PFeZ after reaction.