We performed the size-control synthesis of the Pd nanoparticles (NPs) by means of changing initial Pd concentration in solution. The correlation between hydrogen absorption isotherms (PCT) and particle sizes of Pd was examined by focusing on the size between 5 and 10 nm in diameter. The PCT curve indicated the feature of nanoparticle of Pd with less than 10 nm in diameter, which was different from that of bulk Pd and strongly depended on crystallite size. The hydrogen isotherms of 6.5 and 6.8 nm Pd NPs showed that the final amount of hydrogen was 0.3 at 0.1 MPa and their plateaus were shorten and of gradient. A 5.5 nm NP showed no plateau and realize the nanometer-size regime phenomenon. In the hydrogen absorption of Pd, the size-depending criterion from bulk to nanoparticle experimentally seemed to lie in about 6 nm in diameter.

中文翻译：

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溶液还原法制备的钯纳米粒子储氢性能的尺寸依赖性

我们通过改变溶液中的初始 Pd 浓度来进行 Pd 纳米粒子 (NPs) 的尺寸控制合成。通过关注直径在 5 到 10 nm 之间的尺寸，研究了氢吸收等温线 (PCT) 与 Pd 粒径之间的相关性。PCT曲线表明直径小于10nm的Pd纳米颗粒的特征与块状Pd不同，并且强烈依赖于微晶尺寸。6.5 和 6.8 nm Pd NPs 的氢等温线表明，在 0.1 MPa 下氢的最终量为 0.3，并且它们的平台缩短且呈梯度变化。一个 5.5 nm 的 NP 没有表现出平台，并实现了纳米级的现象。在 Pd 的氢吸收中，从大块到纳米颗粒的尺寸依赖标准在实验上似乎位于直径约 6 nm。