Mechanisms of Oxidase and Superoxide Dismutation-like Activities of Gold, Silver, Platinum, and Palladium, and Their Alloys: A General Way to the Activation of Molecular Oxygen
Mechanisms of Oxidase and Superoxide Dismutation-like Activities of Gold, Silver, Platinum, and Palladium, and Their Alloys: A General Way to the Activation of Molecular Oxygen
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DOI：
10.1021/jacs.5b10346
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发表时间：
2015-12-23
影响因子：
15
通讯作者：
Gao, Xingfa
中科院分区：
文献类型：
--
作者：
Shen, Xiaomei;Liu, Wenqi;Gao, Xingfa
金属和合金纳米材料具有有趣的类氧化酶和类超氧化物歧化（SOD）活性。然而，这些活动的起源仍有待研究。利用密度泛函理论（DFT）计算，我们研究了金属Au，Ag，Pd和Pt以及合金Au 4-xMx（x = 1，2，3; M = Ag，Pd，Pt）的类氧化酶和类SOD性质的机制。我们发现，简单的反应-解离的O-2-负载在金属表面可以深刻地解释了氧化酶类活动的金属。用DET计算的活化能（E-act）和反应能（E-r）可有效地预测活性。作为验证，计算的一系列金属和合金纳米材料的活度级与实验结果非常吻合。简而言之，活性主要取决于两个因素，金属成分和暴露面。在这些结果的基础上，提出了一个基于能量的模型来解释分子氧的活化。对于类SOD活性，其机理主要包括O-2（中心点-）的质子化和HO-2中心点在金属表面的吸附和重排。我们的研究结果为金属的氧化酶和SOD样活性提供了原子级的见解，并为基于金属纳米材料的模拟酶的合理设计铺平了道路。特别是，O-2解离吸附机制将作为一个一般的方式来激活分子氧的纳米表面，并帮助理解的催化作用，纳米材料作为助氧化剂和抗氧化剂。
Metal and alloy nahomaterials have intriguing oxidase- and superoxide dismutation-like (SOD-like) activities. However, origins of these activities remain to be studied. Using density functional theory (DFT) calculations, we investigate mechanisms of oxidase- and SOD-like properties for metals Au, Ag, Pd and Pt and alloys Au4-xMx (x = 1, 2, 3; M = Ag, Pd, Pt). We find that the simple reaction-dissociation of O-2-supported on metal surfaces can profoundly account for the oxidase-like activities of the metals. The activation (E-act) and reaction energies (E-r) calculated by DET can be used to effectively predict the activity. As verification, the calculated activity orders for series of metal and alloy nanomaterials are in excellent agreement with those obtained by experiments. Briefly, the activity is critically dependent on two factors, metal compositions and exposed facets. On the basis of these results, an energy-based model is proposed to account for the activation of molecular oxygen. AS for SOD-like activities, the mechanisms mainly consist of protonation of O-2(center dot-) and adsorption and rearrangement of HO2 center dot on Metal surfaces. Our results provide atomistic-level insights into the oxidase- and SOD-like activities of metals and pave a way to the rational design of mimetic enzymes based on metal nanomaterials. Especially, the O-2 dissociative adsorption mechanism will serve as a general way to the activation of molecular oxygen by nanosurfaces and help understand the catalytic role of nanomaterials as pro-oxidants and antioxidants.