Structural Evolution of Co-Based Metal Organic Frameworks in Pyrolysis for Synthesis of Core–Shells on Nanosheets: Co@CoOx@Carbon-rGO Composites for Enhanced Hydrogen Generation Activity

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• 作者：Congcong Xing ; Yanyan Liu ; Yongheng Su ; Yinghao Chen ; Shuo Hao ; Xianli Wu ; Xiangyu Wang ; Huaqiang Cao ; Baojun Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 22, 2016
• 年：2016
• 卷：8
• 期：24
• 页码：15430-15438
• 全文大小：745K
• 年卷期：0
• ISSN：1944-8252

文摘

In this article, Co-based metal organic frameworks (MOFs) with two shapes were used as pyrolysis precursor to synthesize multilayer core–shells composites loaded on reduced graphene oxide (rGO) sheets. The core–shell structures were obtained by the formation of cores from metal ions and carbon shells from carbonization of ligands. Controllable oxidation of Co cores to CoO_x shells generated multilayer core–shell structures anchored onto the surface of rGO sheets. The N-doped composites were obtained by adding poly vinylpyrrolidone. The multilayer core–shells composites exhibited superior catalytic activity toward hydrogen generation compared to their single layer counterparts. By using the N-doped multilayer composites, high hydrogen generation specific rate of 5560 mL min^–1 g_Co^–1 was achieved at room temperature. The rGO sheets in composites improved their structure stability. These catalysts exhibited high stability after used five cycling. This synergistic strategy proposes simple, efficient, and versatile blue-prints for the fabrication of rGO composites from MOFs-based precursors.