Propiedades catalíticas de grafeno dopado con metales de transición

ABSTRACT In this work a study based on the Density Functional Theory of graphene sheets doped with atoms of Fe, Co and Ni is carried out. The functional PBE1PBE and the pseudopotentials LANL2DZ for the metal atoms, and the 6-31G ++ (d) bases for the carbon atoms were adopted. Three systems formed by the substitution of a carbon atom by one of Fe, Co and Ni, respectively, are analyzed. The energetic, electronic and chemical reactivity properties were studied, making a systematic comparison with a pure graphene sheet. In order to simulate the presence of the solvent in the systems under study, the SCRF = PCM (Self Consistent Reaction Field = Polarizable Continuum Model) was used. In addition, for each system the catalytic properties for O2 adsorption were determined. Our results indicate that the presence of metal heteroatoms and water as solvent modifies the chemical reactivity and the adsorption of dioxygen, which could be determinant on the catalytic properties of doped graphene. The nickel-doped graphene sheet results to be the most reactive and it is the one with the most favorable energy for the adsorption of oxygen.

摘要：本研究基于密度泛函理论（Density Functional Theory），针对铁（Fe）、钴（Co）、镍（Ni）原子掺杂的石墨烯片层开展系统性理论研究。本工作选用PBE1PBE泛函，金属原子采用LANL2DZ赝势（LANL2DZ），碳原子则采用6-31G++(d)基组进行计算。分析了分别以Fe、Co、Ni单原子取代一个碳原子所构建的三种掺杂体系。研究了体系的能量特性、电子结构与化学反应活性，并与纯石墨烯片层进行了系统性对比。为模拟研究体系中的溶剂环境，本研究采用了SCRF=PCM（Self Consistent Reaction Field = Polarizable Continuum Model，即自洽反应场=极化连续介质模型）模型。此外，本研究还测定了各体系对氧气（O₂）吸附的催化性能。研究结果表明，金属杂原子与溶剂水的存在会改变体系的化学反应活性与双原子氧的吸附行为，该效应对掺杂石墨烯的催化性能可能具有决定性影响。其中，镍掺杂石墨烯片层展现出最高的反应活性，且对氧气吸附的结合能最为有利。