Nanostructured catalyst development

BB-SFG, we have investigated CO adsorption on smooth polycrystaHine and singlecrystal electrodes that could be considered model surfaces to those apphed in fuel cell research and development. Representative data are shown in Fig. 12.16 the Pt nanoparticles were about 7 nm of Pt black, and were immobilized on a smooth Au disk. The electrolyte was CO-saturated 0.1 M H2SO4, and the potential was scanned from 0.19 V up to 0.64 V at 1 mV/s. The BB-SFG spectra (Fig. 12.16a) at about 2085 cm at 0.19 V correspond to atop CO [Arenz et al., 2005], with a Stark tuning slope of about 24 cm / V (Fig. 12.16b). Note that the Stark slope is lower than that obtained with Pt(l 11) (Fig. 12.9), for reasons to be further investigated. The shoulder near 2120 cm is associated with CO adsorbed on the Au sites [Bhzanac et al., 2004], and the broad background (seen clearly at 0.64 V) is from nomesonant SFG. The data shown in Figs. 12.4, 12.1 la, and 12.16 represent a hnk between smooth and nanostructure catalyst surfaces, and will be of use in our further studies of fuel cell catalysts in the BB-SFG IR perspective. 

An efficient, low temperature oxidation catalyst was developed based on highly disperse metal catalyst on nanostructured Ti02 support. Addition of dopants inhibits metal sintering and prevents catalyst deactivation. The nanostructured catalyst was formulated to tolerate common poisons found in environments such as halogen- and sulfur-containing compounds. The nanocatalyst is capable of oxidizing carbon monoxide and common VOCs to carbon dioxide and water at near ambient temperatures (25-50 °C). 

The following sections are organized into two parts. The first presents a brief overview of several approaches to preparing nanostructured supports and catalysts that are under current development. Approaches that incorporate building blocks in either part of the system (catalyst or support) will be highlighted. The second part describes a new approach to preparing nanostructured catalysts that we are currently developing in our laboratories. 

Duchateau, R. (2003) Silsesquioxanes advanced model supports in developing silica-immobilized polymerization catalysts, in Nanostructured Catalysts, Kluwer Academic/Plenum Publishers, New York, pp. 57-83. 

Recently, great attention has been dedicated to the development of novel synthetic procedures for the preparation of nanostructured catalysts with superior activity and thermal stability to those currently available. 

Fig. 25 Nanostructured ultrathin film catalyst developed at3M.

For the anode and cathode catalyst development, the unique nanostructured support and catalyst coating methods offer many combinations of materials and process conditions to generate new... 

Nanostructured Catalysts, ed. S.L. Scott, C.M. Crudden and C.W. Jones, Kluwer Academic/Plenum Publishers, New York, N.Y., 2003 R 247 R. Duchateau, Silsesquioxanes Advanced Model Supports in Developing Silica-Immobilized Polymerization Catalysts , p. 57... 

Abstract The goal of catalyst development is to be able to adjust the structure and composition of catalytic materials to obtain the optimal electronic properties for desired chemical reactivity. Key features of the electronic stmcture that influence the reactivity of nanostructured catalysts are reviewed. Conclusions derived from the DPT electronic structure and the surface reactivity computations, with emphasis on the catalyst property intrinsically governed by the local, site-specific interactions, for nanostructured catalysts are presented. 

Therefore, the substantial progress achieved in catalyst development for DRM clearly says that the key to optimize the carbon resistance and promotion of activity lies in good catalyst dispersion and the promotion with adequate basic elements to enhance CO2 adsorption in the DRM reaction. In addition, design and synthesis of novel nanostructures pave the way for future co-implementation of DRM processes in existing industrial systems. 

In the development of fuel ceU catalysts, catalyst synthesis plays a critical role in improving catalyst activity and stability. Over the last several decades, many syntheses methods have been developed, including the impregnation-reduction, colloid, sol-gel, and microwave-assisted methods. Experimental results showed all these methods to be effective in synthesizing catalysts for PEM fuel cells. The most important progress in recent years has been in the synthesis of nanostructured catalysts for fuel cell applications [52]. Nanostractured Pt-based catalysts are claimed to be much more active than the commercially available Pt/C catalysts. 

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