Catalyst arrays

Fig. 3.9 Secondary impregnation workflow showing the precursor preparation station, support preparation, impregnation station, washing station, thermal processing hardware, and impregnated catalyst array.

Willson and Symyx have introduced an alternative infrared thermal imaging technique used for the screening of olefin polymerization catalysts. As with the thermistor technique, the technique is readily adapted to screen catalyst arrays, and exothermic events such as an olefin polymerization can be followed with exquisite sensitivity [14]. Thales Technologies have recently introduced a mecha-... 

Table 3.5 Experimental results fortesting of an Mn/Na2W04/Si02 catalyst array for the oxidative coupling of methane [67],...

The same groups also reported on a 64-fold ceramic block reactor and a ceramic monolithic reactor for the screening of up to 250 catalysts in parallel (Figure 3.41). The catalyst array was prepared via an incipient wetness method by combination of different amounts of Pt, Zr and V on the alumina walls of the monolith by means of an automatic liquid handler. Gas samples from each channel of the monolith were analyzed sequentially by a quadrupole mass spectrometer by moving a capillary sampling line into the channels with the help of a three-dimensional positioning system [69],... 

Scientist are developing an ability to use nanofabrication techniques to make artificially structured catalyst arrays that can drive a chemical reaction to products with dramatically improved energy efficiency and chemical specificity. In general, nanorod structures have been demonstrated in a growing number of solid-state materials a non-exhaustive, but illustrative, list includes the following Si, InP, SiC, ZnO, CdS, GaN, and RuOa [3-8]. Currently it is not possible to predict with certainty what will be the best... 

This preparation method of catalyst array has an advantage, which is that the high surface-area catalysts can be screened under similar circumstances as are used in the traditional half-cell electrochemical testing. An additional advantage is that through this approach, the effect of other chemical/physical variables besides composition can also be studied, for example, variables such as Pt loading and catalyst particle size, as has been done in Guerin s work. 

Besides SECM, other speetroseopie mefliods, such as scanning differential electrochemical mass spectrometry (SDEMS) and IR thermography, were also used as combinatorial screening methods for fuel cell electrocatalysis. The principle of SDEMS is to use mass spectrometry to locally measure dissolved gases and volatile liquid species near flie surfaces of catalyst arrays. IR thermography is based on reaction heat mapping. The heat results from the fuel cell electrochemical reactions on the catalyst arrays. Both methods can obtain reaction... 

Combinatorial methods have also been applied to the area of exploring methanol-tolerant Pt and non-Pt alloy eatalysts for DMFC cathodes. Liu et al. investigated a series of Pt-based and non-Pt binary alloys as ORR electrocatalysts by employing the high-throughput optical screening method. The catalyst arrays were prepared... 

SEM images of the nanowire arrays on different oxides. From the SEM images, the typical dimensions of a single platinum nanowire are 20x5x12 nm. Catalytic oxidation of CO to CO2 over the various catalyst arrays was carried out at temperatures of 513-613 K. Figure 3.4e shows Arrhenius plots for the reaction on zirconia-and ceria-supported samples. Apparent activation energies for the zirconia- and... 

FIGURE 16.1 Catalyst array fabrication, (a) Schematic of the dispenser setup for the preparation of catalyst spots and sequence of steps for the deposition of catalyst precursor solutions, (b) SEM images of typical binary (Pd-Co, top) and ternary (Pd-Au-Co, bottom) catalyst arrays. (Adapted from Fernandez, J.L. et al., J. Am. 

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