Effective Synergistic Effect of Dipeptide-Polyoxometalate-Graphene Oxide Ternary Hybrid Materials on Peroxidase-like Mimics with Enhanced Performance

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• 作者：Zhuo Ma ; Yunfeng Qiu ; Huihui Yang ; Yanmin Huang ; Jingjing Liu ; Yue Lu ; Chen Zhang ; PingAn Hu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 7, 2015
• 年：2015
• 卷：7
• 期：39
• 页码：22036-22045
• 全文大小：545K
• ISSN：1944-8252

文摘

Dipeptide-polyoxometalates (POMs)-graphene oxide (GO) ternary hybrid is an excellent peroxidase-like mimic, exhibiting enhanced peroxidase-like activity compared to POMs alone. The hybrid was readily prepared through a reprecipitation method involving electrostatic encapsulation of H₃PW₁₂O₄₀ (PW₁₂) by cationic diphenylalanine (FF) peptide and coassembly of FF@PW₁₂ spheres with graphene oxide (GO). Using 3,3鈥?5,5鈥?tetramethylbenzidine (TMB) as the chromogenic substrate, the peroxidase-like activity of FF@PW₁₂ was evaluated in the heterogeneous phase, and it is 13 times higher than that of pristine PW₁₂ in the homogeneous phase. Furthermore, ternary hybrids of FF@PW₁₂@GO containing 5 wt % GO could enhance the activity 1.7 times higher than that of FF@PW₁₂. The noncovalent interactions of hydrogen bonding and ionic interaction between GO and POMs are speculated to result in the synergistic effect for the enhancement of peroxidase-like performance. The strong interactions between rGO and PW₁₂ are evaluated by a four-probe Hall measurement via the van der Pauw method, and rGO is significantly p-doped by the doping effect of PW₁₂ with lower LUMO energy than that of the energy level of rGO and also due to the electron reservoir feature of PW₁₂. Cyclic voltammogram measurements also suggest that GO causes significant influence on the electronic structure of the reduced forms of the redox couples of PW₁₂. The nature of the TMB catalytic reaction may originate from the generation of the hydroxyl radical (^{鈥?/sup>OH) from the decomposition of H₂O₂ by ternary hybrids and the formation of peroxo species of POM. Taking advantage of the UV鈥搗is signals of TMB being correlated to the concentration of H₂O₂, FF@PW₁₂@GO can be used to detect H₂O₂ within the limit of detection of 0.11 渭M, and the detection range is 1鈥?5 渭M. The present method indeed opens up a promising route in constructing heterogeneous peroxidase-like mimics through the use of POMs via the introduction of GO for building H₂O₂ sensors.}