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通过两步还原法制备了Pd/Ni双金属催化剂.由于金属Pd原子在先行还原的Ni纳米粒子表面的外延生长以及其在Ni表面和Pd表面生长表现出的吉布斯自由能差异,最终导致了异结构Pd/Ni纳米粒子的形成.高分辨电子透射显微镜结果证实了异结构的存在,然而X射线衍射测量表明Pd/Ni纳米粒子具有类似于Pd的面心立方结构.制备的Pd/Ni纳米粒子与同等条件下合成的Pd纳米粒子相比,对甲酸氧化呈现了更高的电催化活性,而且电催化稳定性也要明显优于纯Pd纳米粒子,证明了Pd/Ni双金属催化剂是可选的直接甲酸燃料电池阳极催化剂.双金属催化剂对甲酸氧化电催化活性和稳定性增强可能是Ni原子的修饰改变了Pd粒子表面配位不饱和原子的电子结构所致.
Pd / Ni bimetallic catalysts were prepared by a two-step reduction method.Due to the differences in Gibbs free energy between the Pd surface and the Ni-Pd surface, The formation of heterostructured Pd / Ni nanoparticles was confirmed by high-resolution transmission electron microscopy (TEM) and X-ray diffraction (XRD) results showed that the Pd / Ni nanoparticles had a face-centered cubic structure similar to Pd. Compared with the Pd nanoparticles synthesized under the same conditions, the nanoparticles exhibited higher electrocatalytic activity for formic acid oxidation and better electrocatalytic stability than pure Pd nanoparticles. It is proved that the Pd / Ni bimetallic catalysts are An alternative direct formic acid fuel cell anode catalyst. The enhanced catalytic activity and stability of the bimetallic catalyst for formic acid oxidation may be due to the modification of the Ni atom that changes the electronic structure of the coordinating unsaturated atom on the Pd particle surface.