Abstract Palladium nanocrystals (Pd NCs) on carbon nanospheres (CNS) are the most important electrocatalysts especially in a direct alcohol fuel cell (DAFC). The shape and size-controlled of Pd NCs are crucial to their electrocatalytic activity. For the first time, we focused on the effect of ultrasound irradiation time interval to build the morphology and size-controlled of Pd NCs. Notably, the functional groups ( COO−, and SO3−) situated on the edges and surfaces of CNS act as an effective capping agent and supporting materials for the growth of various morphology of Pd NCs on CNS surface. In this case, there is no need for an extra stabilizer or reducing agent for the preparation of Pd NCs. The catalytic activity of various Pd-CNS nanocomposites was investigated systematically using an electrochemical workstation. The results have shown that small-sized Pd NCs with a spherical shape had an enhanced activity and stability for alcohol oxidation relative to those of hexagonal Pd NCs and commercial Pd/C. Especially, the spherical Pd-CNS show mass activity 1.6 and 2.8 folds higher than that of hexagonal Pd-CNS and commercial Pd/C, respectively, and significantly maintain high activities after 1000 cycles of intensive durability test.

中文翻译：

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碳纳米球上形状可控的钯纳米晶的合成及其对乙醇和乙二醇的电催化氧化性能

摘要 碳纳米球（CNS）上的钯纳米晶体（Pd NCs）是最重要的电催化剂，尤其是在直接醇燃料电池（DAFC）中。Pd NCs 的形状和尺寸控制对其电催化活性至关重要。我们第一次关注超声照射时间间隔的影响，以构建 Pd NCs 的形态和尺寸控制。值得注意的是，位于 CNS 边缘和表面的官能团（COO-和 SO3-）充当有效的封端剂和支持材料，用于在 CNS 表面上生长各种形态的 Pd NC。在这种情况下，不需要额外的稳定剂或还原剂来制备 Pd NCs。使用电化学工作站系统地研究了各种 Pd-CNS 纳米复合材料的催化活性。结果表明，与六角形 Pd NCs 和商业 Pd/C 相比，具有球形形状的小尺寸 Pd NCs 具有增强的醇氧化活性和稳定性。特别是，球形 Pd-CNS 的质量活性分别比六角形 Pd-CNS 和商用 Pd/C 高 1.6 倍和 2.8 倍，并且在经过 1000 次密集耐久性测试后仍显着保持高活性。