Temperature-programmed reduction profiles

Fig. 2. Temperature-programmed reduction profiles for Ni2P/Si02, Ni2P/Al20j, and Ni2P /C-AI2O3.

Figure 2. Temperature programmed reduction profiles of Cu on zirconia and suifated zirconia with increasing amount of SCf2.

FIGURE 8.1 Temperature-programmed reduction profiles of supported cobalt catalysts, including (top) Co/A1203 catalysts, (middle) Co/Ti02 catalysts, and (bottom) Co/ Si02 catalysts. 

FIGURE 8.3 Temperature-programmed reduction profiles of (top) 25% Co/Si02 and (bottom) 15% Co/Si02, including catalysts calcined using (bold) 5% NO in N2 and (light)... 

Figure 8. Temperature programmed reduction profiles of V2O5/ T1O2 catalysts V8 (8% V2O5), VI (1% V2O5) and of the support EL 10 [28g],...

Fig. 3. Temperature-programmed reduction profiles of (a) Pd/NaY and (b) Pd/MgY after calcination at 500°C (152).

Fig. 13. Temperature-programmed reduction profiles of PdCu/NaY after reoxidation by protons of Cu in PdCu bimetal particles at (A) 350°C and (B) 500°C in an Ar flow. Positive peaks are due to Ha consumption (rate given in arbitrary units) for the reduction of Cu+ (A) attached to Pd and for the reduction of preleached Cu + ions negative peaks are due to Ha evolution from hydride decomposition (.185).

Fig. 14. Temperature-programmed reduction profiles of Pd/NaY after reoxidation to different temperatures following initial calcination to 500°C and reduction at 500°C. The peak at about 0°C is attributed to the reduction of Pd oxide the peak at about 180°C is attributed to the reduction of redispersed Pd ions in sodalite cages (76).

Figure 1,14 Temperature programmed reduction profiles for a supported monometallic catalyst Pd/Al203, for two calcination temperatures.

Figure 2.18. Temperature-programmed reduction profiles of CuZnAlZr oxide catalysts for oxidative steam reforming of methanol. Note that a gradual shift in peak maximum toward lower temperatures, when A1 is substituted by Zr, indicates an improvement in CuO reducibility upon A1 substitution by Zr in the Cu/Zn0-Al203 formulation. Adapted from Velu et al.177...

Figure 1. Temperature programmed reduction profiles of HA (O), HC (O), and HG (A) samples.

Adsorption isotherms of cyclopentane vapours were measured at 20°c. Temperature programmed reduction profiles were measured by the continuous flow technique with a thermal conductivity detector. Simultaneous TG, DTG and DTA were carried out in an argon atmosphere at the heating rate of 10 K.min Catalytic measurements were performed in a continuous flow integral fixed bed reactor under 0.1 MPa at 200°C. The inlet C0/H ratios ranged from 0.5 to 2.0, the space velocity was... 

The temperature-programmed reduction profiles (Fig. 2) for the quaternary catalysts indicate that Ni and Cu reduction take place at different temperatures. However, the reduction of Ni in the Ni-Cu-Zn-Al catalyst occurs at a lower temperature than in the rest of the solids, so that the Cu reduction seems to catalyze the Ni reduction. These facts indicate that the results of catalytic activity obtained in this work can not be due to the formation, at least to any great extent, of an alloy between both metals (Ni and Cu). However, a clear interaction between both metals does exist since the Ni reducibility is clearly modified. 

Figure 2. Temperature programmed reduction profile of 20CoRe/y-Al2O3 after calcination (573 K, 16 h), after reduction (623 K, 16 h) and pulse oxidation (673 K), after reduction (623 K, 16 h) and calcination (573 K, 16 h).

A. Khan, P. Smimiotis, Relationship between temperature-programmed reduction profile and activity of modified ferrite-based catalysts for WGS reaction, J. Mol. Catal. A Chem. 

Figure 4. Temperature-programmed-reduction profiles and relative derivative curves of Ni/Mg/Al HT precursors calcined at different temperatures. (A) Ni/Al= 71.0 29.0 (B) Ni/Mg/Al= 34.0 37.0 29.0 (C) Ni/Mg/Al= 10.0 61.0 29.0 (atomic ratio p cent).

Next question concerns the oxidation state of platinum in Pt/SDB catalysts. Admittedly, X-ray diffraction pattern presented in Ref [12] clearly indicated the presence of Pf, but small amounts of other platinum species (undetected by X-ray technique) possibly can also exist on the catalyst surface. Temperature-programmed reduction profile of SDB-supported R(acac)2 contained two peaks, the first of which corresponded to the reaction of hydrogen with of platinum(Il) acetylacetonate and the second one to the reaction between hydrogen and products of partial decomposition of R(acac)2. X-ray photoelectron spectroscopy (XPS) measurements carried out in the present study have shown the presence of platinum species in the +2 oxidation state, in addition to those in zero oxidation state (Table 15.4). 

The temperature-programmed reduction profiles were obtained by passing 5% H2/Ar gas mixture through the catalyst while increasing the temperature at a linear rate. The amount of samples for all experiments was about 50 mg. The gas flow velocity was 30 ml/min, and the rate of temperature ramping was 3 °C /min... 

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