Preparation Of Different Structured Au-Pt Nanomaterials And Study On Their Eiectrocataiytic Performance

Noble metal nanocrystals (such as gold, silver, and platinum) have received great interest because their electronic, optical, magnetic, and catalytic properties can be tuned by controlling the size, shape, structure, and composition, thus endowing them with greatly potential applications in catalysis, sensing, medical diagnostics and therapeutics, and imaging. Among these noble metal nanocrystals. nanostructured platinum, palladium and gold play very important roles in catalysis. Furthermore, the bimetallic and multimetallic catalysts show excellent catalytic performance that has attracted many researches in the related fields. It should be noted that they are key components in direct methanol fuel cells (DMFCs) because of the higher catalytic performance for methanol oxidation.In this paper, two kinds of Au-Pt nanomaterials of different structure were prepared:(1)Yolk-shell structured Au-Pt nanomaterials. By using spherical Au NCs as seeds and HQ as reductant. Au@Ag NCs with controlled shell thickness were prepared firstly. The Au@Ag NCs with relatively thick shell were then chosen as seeds for synthesis of yolk-shell structured Au-Pt nanomaterials with porous Pt shell by employing a galvanic replacement reaction between K2PtCl4and Ag shell. By adjusting the amount of K2PtCl4. the thichness of porous Pt shell can be tuned in the range from2nm to11.5nm.(2)Hollow structured Au-Pt nanomaterials. By using spherical Ag NCs as sacrificial template, hollow Ag@Au NCs were synthesized by employing a galvanic replacement reaction between HAuCl4and spherical Ag NCs. The diameter of inner and outer, and the Ag proportion in the outer shell can be tuned in some degree by adjusting the amount of HQ. The hollow Ag@Au NCs with high content of Ag in the shell were chosen as seeds for synthesis of hollow structured Au-Pt nanomaterials with porous Pt shell by employing a galvanic replacement reaction between K2PtCl4and Ag in the shell. By adjusting the amount of K2PtCl4. the content of Pt in the shell of the hollow structured Au-Pt nanomaterials can be tuned.Furthermore. the catalytic performance of the two kinds of Au-Pt nanomaterials for methanol oxidation was investigated in acidic and alkaline conditions. For the yolk-shell structured Au-Pt nanomaterials. the sample with2.5nm Pt shell show best catalytic performance for methanol oxidation. For the hollow structured Au-Pt nanomaterials. AuPt32exhibit greatly catalytic performance for methanol oxidation.