Sputtered catalyst library

Preparation of catalyst libraries for the discovery phase can be broadly divided into two categories (1) solution-based methods, and (2) thin-film deposition/based methods. The solution-based methods include those that utilize (1) multi-tasking robotic workstations [14-16] (2) inkjet printhead technology [17], and (3) microjet technology [18]. The thin-film deposition-based methods employ electron beam and thermal evtqroration, sputtering, pulsed laser ablation, and chemical vapor deposition (see [60] in [13] for a list of references). A detailed discussion of how these have been applied is provided elsewhere [13]. Web sites provide links to various aspects of combinatorial chemistry (www.combichem.net and www.5z.com). Here, the hardware aspects are lightly sketched. 

Figure 12.9. Schematic drawing of an assembled electrochemical cell for combinatorial screening catalyst libraries prepared by sputter deposition [22], (Reprinted from Joiunal of Power Sources, 163(1), Cooper JS, McGinn PJ. Combinatorial screening of thin film electrocatalysts for a direct methanol fuel cell anode, 330-8, 32006, with permission from Elsevier.)...

Cong and co-workers [54] have prepared a ternary library of transition metals by sputter deposition on a quartz wafer. The catalyst samples were supplied with reactants through a concentric tube that also delivered the product gas flow to a sensor for spectroscopic analysis (see Chapter 3). The catalysts could be activated by a C02 heating laser from the backside of the wafer. 

CO oxidation on a quartz wafer has been examined by the group of Weinberg [54]. They prepared catalyst samples by co-sputtering of the individual targets and by sol-gel techniques on a quartz wafer. The time for the preparation of a sputtered library is said to be only 1 h. A ternary library consisting of Pd, Pt and Rh exhibited sensitivity to C02 production, with the highest product yield in Pd-rich catalysts. 

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