A Graphene Composite Material with Single Cobalt Active Sites: A Highly Efficient Counter Electrode for Dye-Sensitized Solar Cells

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• 作者：Xiaoju Cui ; Dr. Jianping Xiao ; Dr. Yihui Wu ; Peipei Du ; Prof. Rui Si ; Prof. Huaixin Yang ; Prof. Huanfang Tian ; Prof. Jianqi Li ; Prof. Wen-Hua Zhang ; Prof. Dehui Deng and Prof. Xinhe Bao
• 刊名：Angewandte Chemie International Edition
• 出版年：2016
• 出版时间：June 1, 2016
• 年：2016
• 卷：55
• 期：23
• 页码：6708-6712
• 全文大小：2109K
• ISSN：1521-3773

文摘

The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN₄/GN is a highly active and stable counter electrode for the interconversion of the redox couple I⁻/I₃⁻. DFT calculations revealed that the superior properties of CoN₄/GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN₄ /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart.