title: Facile synthesis of Pd-Pt alloy nanocages and their enhanced performance for preferential oxidation of CO in excess hydrogen.
abstract: This article describes a new method for the facile synthesis of Pd-Pt alloy nanocages with hollow interiors and porous walls by using Pd nanocubes as sacrificial templates. Differing from our previous work (Zhang, H.; Jin, M. S.; Wang, J. G.; Li, W. Y.; Camargo, P. H. C.; Kim, M. J.; Yang, D. R.; Xie, Z. X.; Xia, Y. Synthesis of Pd-Pt Bimetallic Nanocrystals with a Concave Structure through a Bromide-Induced Galvanic Replacement Reaction. J. Am. Chem. Soc.2011, 133, 6078-6079), we complemented the galvanic replacement (between Pd nanocubes and PtCl(4)(2-)) with a coreduction process (for PdCl(4)(2-) from the galvanic reaction and PtCl(4)(2-) from the feeding) to generate Pd-Pt alloy nanocages in one step. We found that the rate of galvanic replacement (as determined by the concentrations of Br(-) and PtCl(4)(2-) and temperature) and the rates of coreduction (as determined by the type of reductant and temperature) played important roles in controlling the morphology of resultant Pd-Pt alloy nanocages. The Pd-Pt nanocages exhibited both enhanced activity and selectivity for the preferential oxidation (PROX) of CO in excess hydrogen than those of Pd nanocubes and the commercial Pt/C thanks to the alloy composition and hollow structure. In addition, as the sizes of the Pd-Pt nanocages decreased, they exhibited higher CO conversion rates and lower maximum conversion temperatures due to the increase in specific surface area.
authors: Department of Biomedical Engineering,  Washington University , St. Louis, Missouri 63130, United States.
authors: Hui
authors: H
authors: Zhang
authors: Mingshang
authors: M
authors: Jin
authors: Hongyang
authors: H
authors: Liu
authors: Jinguo
authors: J
authors: Wang
authors: Moon J
authors: MJ
authors: Kim
authors: Deren
authors: D
authors: Yang
authors: Zhaoxiong
authors: Z
authors: Xie
authors: Jingyue
authors: J
authors: Liu
authors: Younan
authors: Y
authors: Xia
mesh_terms: D000497:Alloys / Q000737:chemistry*; D002248:Carbon Monoxide / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D006859:Hydrogen / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D016062:Porosity; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000497:Alloys; D010984:Platinum; D010165:Palladium; D002248:Carbon Monoxide; D006859:Hydrogen