Sintering catalyst load effect

Fig. 9.1. Effect of catalyst load and the presence of a support on the sintering of a catalyst, a) Unsupported powdered catalyst b) high load supported catalyst c) low load supported catalyst.

Next, we examined the effects of control of the microstnicture such as pore-size distribution (or porosity) and the ohmic resistance of SDC layers on the improvement of the electrocatalytic activity of the SDC anode with and without nm-sized Ru metal catalyst loading. Fine polymer beads (cross-linked polystyrene, d = 1.2 pm) were added to the SDC paste, resulting in the fonnation of pm-sized pores after sintering, which can improve the gas-diffusion rates in the electrode. 

The Effect Of Catalyst Loading On The Sintering Of Supported Pd/AhOa Automotive Catalysts... 

Figure 4. Effects of hydrogen and oxygen atmospheres and of metal loading on sintering rates of 0.6% and 5% Pt/alumina catalysts [28,331.

Thermal sintering of Ti02 greatly enhanced the chemical activity of the catalyst, in spite of the contraction of surface area. The catalyst calcined at 800°C was twice as active as the fresh catalyst towards SO3 formation. The progressive formation of V-agglomerates consequent to sintering produced a comparable effect than an increase of V-load. It is known from the literature that polymeric V-species show much higher oxidation activity than dispersed species accurate dispersion of a little amount of V is indeed fundamental for the preparation of active and selective SCR catalysts. 

In another test, the washcoated ceramic foam was loaded with 0.7 wt% Rh by impregnation with RhClj- 3H2O solution. The catalyst was sintered at various temperatures for 2 h and the results are given in Table 5. Dispersion of the metal is fairly constant until above 600°C, dropping considerably at 1000°C. These results demonstrate that ceramic foams may be effectively washcoated with efficient stabilization of supported catalysts. 

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