文献类型：期刊文献

英文题名：Revealing the Volcano-Shaped Activity Trend of Triiodide Reduction Reaction: A DFT Study Coupled with Microkinetic Analysis

作者：Wang, Dong[1,2,3];Jiang, Jun[1,2];Wang, Hai-Feng[1,2];Hu, P.[1,2,3]

机构：[1]E China Univ Sci & Technol, Key Lab Adv Mat, Ctr Computat Chem, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Res Inst Ind Catalysis, Shanghai 200237, Peoples R China;[3]Queens Univ Belfast, Sch Chem & Chem Engn, Belfast BT9 5AG, Antrim, North Ireland

年份：2016

卷号：6

期号：2

起止页码：733

外文期刊名：ACS CATALYSIS

收录：;EI(收录号：20160701916597);WOS:【SCI-EXPANDED(收录号:WOS:000369774900030)】；

基金：This work was supported by the Science Fund of Creative Research Group (21421004), National Natural Science Foundation of China (21333003, 21303052), Shanghai Rising-Star Program (14QA1401100) and ChenGuang project (13CG24), the Commission of Science and Technology of Shanghai Municipality (12ZR1442600), Fundamental Research Funds for the Central Universities. D.W. thanks the Chinese Scholarship Council for the abroad living support.

语种：英文

外文关键词：triiodide reduction; I-3(-)/I-; dye-sensitized solar cells; BEP relation; microkinetic analysis; volcano curve; electrocatalysis; density functional theory

摘要：Triiodide/iodide (I-3(-)/I-) represents a widely used redox couple and plays an important role in some photovoltaic devices. However, the understanding of the triiodide reduction kinetics occurring at the liquid/electrode interface is very limiting, which largely hinders the identification of highly efficient electrode material. In this work, by virtue of DFT calculations, we systematically investigated the I-3(-) electroreduction at some acetonitrile/electrode interfaces and uncovered two new BEP relations for the key elementary steps, I-2 dissociation and I* desorption through one-electron reduction. Furthermore, by utilizing a steady-state microkinetic model, we successfully identified a general volcano-shaped activity trend of triiodide electroreduction as a function of a single descriptor, the adsorption energy of I atom (E-ad(I)) at the interface. Our results show that a good catalyst should possess an E-ad(I) within the range of 0.3-0.6 eV, while the optimal E-ad(I) is 0.43 eV, where the surface coverages of free sites and iodine atoms are equal. In particular, the dependences of the volcano shape on the electrochemical conditions (external voltage, temperature, concentration, and transfer coefficient) are quantitatively discussed. Some suggestions for the optimization of experimental conditions and design of better catalysts are also provided.