2005年12月5日
科学家首次将氢原子操纵到钯晶体表面下方的稳定部位，从而形成了一种在金属催化剂，氢存储和燃料电池中预测至关重要的结构。该研究将于2005年12月13日发表在《杂志》上国家科学院论文集欧洲杯线上买球。
Observations of the effects of the resulting subsurface hydrides--hydrogen atoms with a partial negative charge--confirmed the existence of the stable sites, which had been predicted but previously had neither been deliberately assembled nor directly observed. The research was led by Paul S. Weiss, Distinguished Professor of Chemistry and Physics at宾夕法尼亚州。
在将吸收的氢原子移动到晶体表面下方之后，研究人员能够观察金属晶体内特定部位的氢化物的存在如何影响金属的化学，物理和电子特性。了解这些影响可以促进改善涉及金属催化剂的化学反应的努力。此外，地下氢化物可以提供用于在氢存储和燃料电池中应用的模型材料。准备地下氢化物的能力为这些应用提供了重要的研究工具。
Weiss points out that hydrogen atoms just below the surface of the metal have been thought to be important in a number of chemical reactions. "Indirect experimental data have shown that chemically reactive hydrogen atoms were located at such sites, but there was no way to test them," says Weiss. "This material will allow us to test the predictions and to apply data from direct observation."
研究人员通过将晶体暴露于氢气中，在超高真空下进行低温扫描隧道显微镜（STM）进行了实验。他们通过暴露于热量和氧气的循环从表面上去除了多余的氢。清洁表面后，研究人员能够使用STM尖端的电子将被吸收到块状金属吸收到稳定地下位点的氢原子中。当氢化物在材料表面下方形成时，魏斯和他的团队观察到晶体的表面扭曲了它们上方的钯原子的正电荷增加，并且与钯晶体表面上的氢原子发生相互作用。魏斯说：“这项研究最有趣的方面之一是能够将原子移动到表面下。”“观察人口稠密的位点的作用，例如表面扭曲，证实了稳定部位的存在以及氢化物的物理和电性能的理论预测。”
Years ago, Weiss was the first on an IBM team to manipulate xenon atoms on a metal surface. His coworkers later moved atoms to spell out their corporate logo. By extending the ability to manipulate atoms beyond the surface of a material, this research is expected to advance the understanding and control of important chemical reactions in a variety of commercial applications. In addition, this ability has potential as a model system of a technologically important material.
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