title: 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.
abstract: Metal and alloy nanomaterials 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 O2-supported on metal surfaces can profoundly account for the oxidase-like activities of the metals. The activation (Eact) and reaction energies (Er) calculated by DFT 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 O2(•-) and adsorption and rearrangement of HO2(•) 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 O2 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.
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangxi Normal University , Nanchang 330022, China.|CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Shen
authors.affiliation: CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China , Beijing 100190, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Gao
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangxi Normal University , Nanchang 330022, China.
authors.forename: Zhanghui
authors.initials: Z
authors.lastname: Lu
authors.affiliation: CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China , Beijing 100190, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Wu
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangxi Normal University , Nanchang 330022, China.|CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xingfa
authors.initials: X
authors.lastname: Gao
mesh_terms: D006046:Gold / Q000494:pharmacology*; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010165:Palladium / Q000494:pharmacology*; D010984:Platinum / Q000494:pharmacology*; D012834:Silver / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D012834:Silver; D010984:Platinum; D010165:Palladium; D006046:Gold; D010088:Oxidoreductases; D013482:Superoxide Dismutase; D010100:Oxygen