Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Angew Chem Int Ed Engl. 2017 Oct 9;56(42):12952-12957. doi: 10.1002/anie.201706647. Epub 2017 Sep 7.
Interactions between oxygen and gold surfaces are fundamentally important in diverse areas of science and technology. In this work, an oxygen dimer structure was observed and identified on gold nanoparticles in catalytic decomposition of hydrogen peroxide to oxygen and water. This structure, which is different from isolated atomic or molecular oxygen surface structures, was observed with in situ surface-enhanced Raman spectroscopic measurements and identified with density functional theory calculations. The experimental measurements were performed using monodisperse 5, 50 and 400 nm gold particles supported on silica with liquid-phase hydrogen and deuterium peroxides at multiple pH values. The calculations show that on surfaces with coordinatively unsaturated gold atoms, two oxygen atoms preferentially share a gold atom with a bond distance of 0.194-0.196 nm and additionally bind to two other surface gold atoms with a larger bond distance of 0.203-0.213 nm, forming an Au-O-Au-O-Au structure. The formation of this structure depends on reaction rates and conditions.
氧与金表面的相互作用在科学技术的多个领域都具有重要的基础意义。在这项工作中，我们在金纳米颗粒催化过氧化氢分解为氧和水的过程中观察到并确定了氧二聚体结构。这种结构与孤立的原子或分子氧表面结构不同，通过原位表面增强拉曼光谱测量进行了观察，并通过密度泛函理论计算进行了识别。实验测量是在多个 pH 值下使用负载在二氧化硅上的 5、50 和 400nm 金颗粒，用液相过氧化氢和过氘进行的。计算表明，在具有配位不饱和金原子的表面上，两个氧原子优先与一个金原子共享一个键距为 0.194-0.196nm 的键，并且另外与两个其他表面金原子结合，形成一个 Au-O-Au-O-Au 结构。该结构的形成取决于反应速率和条件。
