Development of New Gold Catalysts for Removing CO from

Heterogeneous Catalysis at Nanoscale for Energy Applications, First Edition. Edited by Franklin (Feng) Tao, William F. Schneider, and Prashant V. Kamat. 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

CO elimination, in Hj-rich stream, can be achieved by the water-gas shift reaction (WGS CO+HjO = C02 + Hj) and the preferential oxidation of CO (PROX CO + 1/202=C0,) [5-7]. These two reactions are complementary. WGS is usually carried out at relatively high temperatures compared to PROX and the CO to be eliminated is of higher concentration. In addition, PROX can remove CO (after undergoing WGS, the concentration of CO is lower, and the CO+H mixture cools down). 

Although many metal oxide catalysts and supported noble metal catalysts have been developed for WGS and PROX [5-7], catalysts with better performance are still desired. The development of new catalysts is not only important for achieving better activity, selectivity, and stability of catalysts, but also important for gaining fundamental insights (e.g., nature of active sites, reaction mechanisms, and deactivation mechanisms). Gaining fundamental insights can not only satisfy scientists curiosity, but also help in developing better catalysts. 

In this chapter, we highlight the development of gold catalysts for WGS and PROX. There are many relevant publications dealing with the development of WGS and PROX catalysts for these reactions, optimization of catalysts, nature of active sites, reaction mechanisms, and deactivation mechanisms [15-19]. The chapter is not intended to be comprehensive. Rather, examples on the development of new gold catalysts for WGS and PROX will be highlighted and some thoughts on the insufficiencies of the current research as well as some perspectives on future research will be furnished. 

FIGURE 10.1 TEM image showing the dispersion of numerous tiny gold nanoparticles on an amorphous SiO support. Reprinted with permission from Ref. [21]. Elsevier B.V. 

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