催化学报

催化学报 ›› 2021, Vol. 42 ›› Issue (2): 251-258.DOI: 10.1016/S1872-2067(20)63650-6

• 论文 • 上一篇    下一篇

可持续固相合成高分散PdAg合金纳米颗粒用于电催化氢氧化和氢析出反应

徐才丽a, 陈倩a, 丁蓉a, 黄生田b, 张云a,*(), 樊光银a,#()   

  1. a四川师范大学化学与材料科学学院, 四川成都610068
    b四川轻化工大学绿色催化四川省高等学校重点实验室, 四川自贡643000
  • 收稿日期:2020-03-31 接受日期:2020-05-07 出版日期:2021-02-18 发布日期:2021-01-21
  • 通讯作者: 张云,樊光银
  • 基金资助:
    国家自然科学基金(21905187);国家自然科学基金(21777109);绿色催化四川省高等学校重点实验室(LZJ1802)

Sustainable solid-state synthesis of uniformly distributed PdAg alloy nanoparticles for electrocatalytic hydrogen oxidation and evolution

Caili Xua, Qian Chena, Rong Dinga, Shengtian Huangb, Yun Zhanga,*(), Guangyin Fana,#()   

  1. aCollege of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610068, Sichuan, China
    bKey Laboratory of Green Catalysis of Higher Education Institutes of Sichuan, College of Chemistry and Environment Engineering, Sichuan University of Science and Engineering, Zigong 643000, Sichuan, China
  • Received:2020-03-31 Accepted:2020-05-07 Online:2021-02-18 Published:2021-01-21
  • Contact: Yun Zhang,Guangyin Fan
  • About author:#E-mail: fanguangyin@sicnu.edu.cn
    *Tel/Fax: +86-28-84760802; E-mail: zhangyun@sicnu.edu.cn;
  • Supported by:
    National Natural Science Foundation of China(21905187);National Natural Science Foundation of China(21777109);Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan(LZJ1802)

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摘要：

固相研磨作为一种新型可持续的合成方法, 近年来引起了人们广泛关注,为负载型金属合金纳米催化剂的制备提供了新思路. 尽管有关合金催化剂研究取得了系列进展, 但现有制备方法大多存在操作步骤复杂、形貌难以控制等问题,严重制约了合金催化剂的规模化应用. 本文发展了一种可持续化策略, 即于室温下在玛瑙研钵中直接研磨合成了一系列高分散在碳载体上的小尺寸PdAg合金纳米颗粒(PdAg/C). 此法无需任何溶剂和有机试剂, 保证了整个过程简单便捷、绿色环保, 同时确保了PdAg合金纳米颗粒表面清洁无污染, 利于样品的催化应用. 利用TEM,XRD和XPS表征技术对系列PdAg/C样品的组成及形貌进行了深入探究. TEM结果表明, 所得催化剂中金属颗粒尺寸较小(4.9±1.03 nm),且高度分散在碳载体表面. XRD结果表明, Pd9Ag1/C,Pd5Ag5/C和Pd1Ag9/C催化剂特征衍射峰位于对应的Pd/C和Ag/C衍射峰之间, 且会随着Ag含量的不断增加逐渐向低角度偏移. XPS结果表明, 三个催化剂中均存在Pd,Ag两种元素,且随着Ag含量的增加, 它们的Pd 3d结合能逐渐正移;而随着Pd含量的不断增加, 三样品的Ag 3d结合能逐渐负向偏移. 由此可见,采用可持续固相合成法成功制得了碳负载的PdAg合金纳米颗粒. 一系列对比实验表明,PdAg合金纳米颗粒的尺寸和分散度显著依赖于NaOH,而与碳载体的形貌、比表面积和类型无明显关系. 将系列PdAg/C样品用于碱性电催化氢氧化(HOR)和析氢反应(HER)时, 均展现出高的催化性能. 其中, Pd9Ag1/C催化性能最佳, 在HOR中, 质量交换电流密度和面积交换电流密度分别为26.5 A gPd-1和0.033 mA cmPd-2; 在HER中, 电流密度为10 mA cm-2时所需过电位仅为68 mV; 此外, Pd9Ag1/C催化剂经过1000圈CV循环测试后, 催化活性未显著衰减, 对两个目标反应均展现出优异的电化学稳定性. PdAg/C高催化活性主要归因于两个方面: (1) PdAg合金纳米颗粒表面洁净、尺寸小且分散均匀, 能提供大量可利用的活性位点; (2) Pd与Ag之间强的协同与合金效应使得催化剂具有最佳的本征活性.

关键词: 固相合成, 负载型合金纳米颗粒, 电催化, 氢氧化反应, 氢气析出反应

Abstract:

New sustainable syntheses based on solid-state strategies have sparked enormous attention and provided novel routes for the synthesis of supported metallic alloy nanocatalysts (SMACs). Despite considerable recent progress in this field, most of the developed methods suffer from either complex operations or poorly controlled morphology, which seriously limits their practical applications. Here, we have developed a sustainable strategy for the synthesis of PdAg alloy nanoparticles (NPs) with an ultrafine size and good dispersion on various carbon matrices by directly grinding the precursors in an agate mortar at room temperature. Interestingly, no solvents or organic reagents are used in the synthesis procedure. This simple and green synthesis procedure provides alloy NPs with clean surfaces and thus an abundance of accessible active sites. Based on the combination of this property and the synergistic and alloy effects between Pd and Ag atoms, which endow the NPs with high intrinsic activity, the PdAg/C samples exhibit excellent activities as electrocatalysts for both the hydrogen oxidation and evolution reactions (HOR and HER) in a basic medium. Pd9Ag1/C showed the highest activity in the HOR with the largest j0,m value of 26.5 A g Pd-1 and j0,s value of 0.033 mA cmPd -2, as well as in the HER, with the lowest overpotential of 68 mV at 10 mA cm-2. As this synthetic method can be easily adapted to other systems, the present scalable solid-state strategy may open opportunity for the general synthesis of a wide range of well-defined SMACs for diverse applications.

Key words: Solid-state synthesis, Supported metallic alloy nanoparticles, Electrocatalysis, Hydrogen oxidation reaction, Hydrogen evolution reaction