胶体法制备高活性Pt-Ni双金属纳米粒子及其甲醇催化性能研究

Colloidal Synthesis Highly Active Pt-Ni bi-metallic Nanoparticles and Study of its Methanol Electrocatalytic Properties

摘要:

采用胶体法分别以乙酰丙酮铂（Pt(acac)2）和乙酸镍（Ni(ac)2?4H2O）为前驱体制备了（1:3；1:1；3:1）不同摩尔比的Pt-Ni合金纳米粒子，将其负载在XC-72碳黑载体获得Pt-Ni/C双金属催化剂，其中Pt3Ni/C催化剂催化活性最高，其正向扫描峰电流密度是42.5 mA?cm-2，分别是PtNi/C、PtNi3/C 和Pt/C催化剂的 3.2、5.3和 1.2倍；而催化剂抗中毒能力则是PtNi3/C最强(If/Ib值为23.5)。TEM和XRD表征表明Pt-Ni双金属纳米粒子单分散性好，粒径分布为2~4 nm；同时XPS结果表明Ni的掺杂改变了Pt的外层电子层结构，减少了表面Pt原子对CO的吸附，释放出更多的Pt活性位，从而提高了Pt-Ni/C双金属催化剂的电催化活性和抗中毒能力。

Abstract:

Pt-Ni alloy nanoparticles with different atomic ratios of Pt to Ni (1:3；1:1；3:1) were prepared by colloidal synthesis method with Pt(acac)2 and Ni(ac)2?4H2O as precursors, respectively, and Pt-Ni/C bi-metallic catalysts were obtained after the nanoparticles were loaded on the surface of XC-72 carbon supports, and Pt3Ni/C catalysts displayed the best catalytic activity. The peak current density of Pt3Ni/C catalyst was 42.5 mA.cm-2 at the positive scanning, which was 3.2, 5.3 and 1.2 times as high as those of PtNi/C, PtNi3/C and Pt/C catalysts, and else the anti-poisoning ability of PtNi3/C was the strongest (If/Ib was 23.5) contorted with other samplers. TEM and XRD analysis indicated that Pt-Ni bi-metallic nanoparticles are uniformly distributed with the sizes ranging from 2 to 4 nm, and XPS demonstrated that the addition of Ni changes the external electronic structure of Pt, reduces the absorption of CO on Pt and releases more Pt active sites, which was the reason for the electrocatalytic activity and anti-poisoning ability of Pt-Ni/C catalyst improved.