Noble-metal based catalysts with high dispersion have been extensively applied in Chemical engineering process. To obtain metal catalyst with higher dispersion by change or optimizing the preparation method is a grand challenge. Recently, the research group leaded by Prof. Tao Zhang and Prof. Xiaodong Wang made a great progress in synthesis of highly dispersed Ir based catalyst. The developed new Ir/Fe(OH)_x catalyst exhibits an excellent performance in CO oxidation and preferential CO oxidation, even comparable to the Au based catalyst. More importantly, the preparation method is versatile and can be extended to other Pt group metal catalyst. The research results were published on-line in the Angew. Chem. Int. Ed.

(http://onlinelibrary.wiley.com/doi/10.1002/anie.201106702/abstract)。

Small amounts of CO present in the H₂ stream poison the Pt electrocatalysts of polymer electrolyte membrane fuel cells (PEMFCs). Preferential CO oxidation (PROX) is one of the most effective methods for reducing CO to the desired level without excessive H₂ consumption. To this end, various catalyst formulations, especially the Au-based ones, have been developed. Comparatively, the Prof. Zhang’s research group made continuous effort on the development of Pt- and Ir-based PROX catalyst and their reaction mechanism (J. Catal. 2008, 255, 144; J. Phys. Chem. C 2010, 114, 8533; Ind. Eng. Chem. Res. 2011, 50, 758; Chem. Eng. J. 2011, 168, 822; Nat. Chem. 2011, 3, 634). They not only developed a novel single atom Pt catalyst and a series of new Ir-based catalyst but also extensively investigated their reaction mechanism for PROX. Based on the understanding that the adsorption of O₂ can be greatly promoted by using a material containing or easily transformed to Fe²⁺, they selected a special support of Fe(OH)_x to improve the activation of O₂. Furthermore, the Ir particle was highly dispersed on this support in a subnano scale (< 1 nm). the adsorption microcalorimetry and ftir technique demonstrated the important role of this support on the promotion of o₂ activation. Compared with the standard Au/Fe₂O₃ catalyst from World Gold Council, this Ir/Fe(OH)_x was not only highly active for PROX reaction at room temperature but also provided a wider temperature window (20-60℃).This work offered a new avenue to develop a high performance PROX catalyst.