In-situ grafting of N-doped carbon nanotubes with Ni encapsulation onto MOF-derived hierarchical hybrids for efficient electrocatalytic hydrogen evolution. (15th August 2020)

• Record Type: Journal Article
• Authors: Cheng, Ningyan; Wang, Nana; Ren, Long; Casillas-Garcia, Gilberto; Liu, Nana; Liu, Yani; Xu, Xun; Hao, Weichang; Dou, Shi Xue; Du, Yi
• Is Part Of: Carbon. Volume 163(2020)
• Page Start: 178
• Page End: 185
• Publication Date: 2020-08-15
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2020.03.017
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Developing highly efficient and cost-effective catalysts for the hydrogen evolution reaction (HER) is of paramount importance to solve the problems arising from the depletion of non-renewable fossil fuels and increasing air pollution issues. Herein, an in-situ heterogeneous catalytic synthesis approach is developed for constructing hierarchical Ni/carbon hybrids via grafting nitrogen-doped-carbon (NC) nanotubes with Ni encapsulation onto the metal-organic framework (MOF)-derived carbon matrix. Following the "nanotube tip-growth model" involved in the in-situ catalytic synthesis process, the morphology and size of the nanotubes and encapsulated particles of the as-prepared hierarchical Ni-based carbon hybrids can be controlled by regulating the conditions during the thermal decomposition of the Ni-MOF in the presence of melamine. The grafting and decoration of the Ni-encapsulated carbon nanotubes on the MOF-derived architecture rapidly enhance the HER electrocatalytic performance of the bare thermally decomposed Ni/N-doped carbon composite. Due to the synergistic effects of the stable metallic Ni active sites and the N-doped carbon support, the optimized Ni@NC6 -600 sample exhibits stable and high catalytic activity, only requiring an overpotential of 181 mV to drive 10 mA/cm 2 towards the HER in alkaline media. Graphical abstract: Ni-encapsulated N-doped multi-layer CNTs, which adopts the "tip-growth model" for CNTs, were successfully grown by thermal decomposition of a Ni-based metal-organic framework (MOF) in the presence of melamine vapour. It has been demonstrated that the annealing temperature and the ratio of the melamine to Ni(dmg)2 could affect the final structure and catalytic properties of the as-prepared Ni@NC x -T. Due to the synergistic effects of the structure and composition, the optimized Ni@NC6 -600 exhibits the highest catalytic activity and stability, only requiring an overpotential of 181 mV to drive 10 mA/cm 2 . Image 1