Highly Active Carbon Supported Pd–Ag Nanofacets Catalysts for Hydrogen Production from HCOOH

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• 作者：Wenhui Wang ; Ting He ; Xuehua Liu ; Weina He ; Hengjiang Cong ; Yangbin Shen ; Liuming Yan ; Xuetong Zhang ; Jinping Zhang ; Xiaochun Zhou
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 17, 2016
• 年：2016
• 卷：8
• 期：32
• 页码：20839-20848
• 全文大小：515K
• 年卷期：0
• ISSN：1944-8252

文摘

Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd–Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd–Ag alloy nanofacets, such as Pd–Ag{111}, Pd–Ag{100}, and Pd–Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd–Ag{hcp} > Pd–Ag{111} > Pd–Ag{100}. Particularly, the activity of Pd–Ag{hcp} is up to an extremely high value, i.e., TOF_{hcp} = 19 000 ± 1630 h^–1 at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd–Ag alloy nanocatalyst. The initial activity of Pd–Ag{hcp} even reaches (3.13 ± 0.19) × 10⁶ h^–1 at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst.