题目：Tuning the Electrocatalytic Performance ORR Catalysts through Ionic Liquid Modification

　　报告人：Prof. Bastian J. M. Etzold

　　　　　　德国达姆施塔特工业大学　　

　　时间：2018年11月16日（周五），上午09:30-11:30

　　地点：李薰楼468室

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　　报告摘要： 

　　Modifying Pt catalysts using hydrophobic ionic liquids (ILs) has been demonstrated as a facile approach to boosting the performance of Pt catalysts for ORR. This work aims to deepen the understanding and initiate a rational molecular tuning of IL for improved activity and stability. To this end, Pt/C catalysts were modified using a wide variety of [CnC1im][NTf₂] ILs with varying alkyl chain lengths in imidazolium cations, and their electrocatalytic properties were systematically investigated. It is disclosed that the catalytic activity strongly correlates with the alkyl chain length of cations, and a distinct dependence of intrinsic activity on the alkyl chain length with the maximum activity obtained on the Pt/C-[C4C1im][NTf2] was identified. The optimum arises from the counterbalance between more efficient suppression of oxygenated species formation on Pt surfaces and more severe passivation of Pt surfaces with elongation of the alkyl chain length in imidazolium cations. Moreover, the presence of IL can also improve the electrochemical stability of Pt catalysts by suppressing the Pt dissolution, as evidenced by the identical-location TEM and in situ ICP-MS analyses. We believe that these findings could be exploited to develop active and stable Pt-saving electrocatalysts for fuel cell catalysis and may also have broad implications for constructing other high-performing catalytic systems by using ionic liquid modifications.