Correlation of Surface Ag Content in AgPd Shells of Ultrasmall Core鈥揝hell Au@AgPd Nanoparticles with Enhanced Electrocatalytic Performance for Ethanol Oxidation

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• 作者：Tingting Miao ; Yahui Song ; Cuixia Bi ; Haibing Xia ; Dayang Wang ; Xutang Tao
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 13, 2015
• 年：2015
• 卷：119
• 期：32
• 页码：18434-18443
• 全文大小：615K
• ISSN：1932-7455

文摘

We report the synthesis of well-dispersed, ultrasmall, core鈥搒hell (CS) Au@AgPd nanoparticles (NPs) via galvanic reaction of Ag shells of CS Au@Ag NPs with Pd²⁺ ions at room temperature. It is found that Ag content in the resulting AgPd shells is dependent mainly on the thickness of the original Ag shells and the concentrations of Pd²⁺ ions used for the galvanic reaction. In addition, the electrocatalytic performance of the resulting CS Au@AgPd NPs is dependent on the surface Ag content (s-Ag_nPd_1鈥?i>n) in the AgPd shells (where s-Ag_nPd_1鈥?i>n is added to highlight the surface Ag content) while being independent of the total Ag content. When the ultrathin AgPd shells with 0.79 nm thickness and the surface Ag content of about 29.4% are formed on ca. CS_0.60 Au@Ag NPs, the resulting CS_0.60 Au@AgPd-s-Ag_0.294Pd_0.706 NPs with average size of 8.5 nm have significantly increased electrochemically active surface area (up to 77.5 m²鈥痝^鈥?) and exhibit superior catalytic activity (1.16 A鈥痬g_Pd^鈥?) toward ethanol oxidation (0.50 M) in alkaline media (0.30 M KOH), about 5 times higher than that of commercial Pd/C catalyst (0.20 A鈥痬g_Pd^鈥?).