Hollow Carbon‐Based Nanoarchitectures Based on ZIF: Inward/Outward Contraction Mechanism and Beyond

Abstract

Hollow carbon‐based nanoarchitectures (HCAs) derived from zeolitic imidazolate frameworks (ZIFs), by virtue of their controllable morphology and dimension, high specific surface area and nitrogen content, richness of metal/metal compounds active sites, and hierarchical pore structure and easy exposure of active sites, have attracted great interests in many fields of applications, especially in heterogeneous catalysis, and electrochemical energy storage and conversion. Despite various approaches that have been developed to prepare ZIF‐derived HCAs, the hollowing mechanism has not been clearly disclosed. Herein, a specialized overview of the recent progress of ZIF‐derived HCAs is introduced to provide an insight into their preparation strategy and the corresponding hollowing mechanisms. Based on the fundamental understanding of the structural evolution of ZIF nanocrystals during the high‐temperature pyrolysis process, the hollowing mechanisms of ZIF‐derived HCAs are classified into four categories: i) inward contraction of core–shell template@ZIF composites or hollow ZIFs, ii) outward contraction of ZIF@shell composites, iii) special outward contraction of ZIF arrays, and iv) mechanism beyond inward/outward contraction of pure ZIF nanocrystals. Finally, an outlook on the development prospects and challenges of HCAs based on ZIF precursors, especially in terms of controlled synthesis and future electrochemical application, is further discussed.

Enriching Atomic Cobalt in an Ultrathin Porous Carbon Shell for Enhanced Electrocatalysis

“…Pyrolysis of metal organic framework (MOF) has recently become an important strategy to prepare M/NC electrocatalysts. − MOFs as preassembled periodically with metal nodes and organic ligands are ideal platforms to deliver carbon electrocatalysts consisting of transition metal–nitrogen coordinates (M-N x /C). Li’s research group reported a series of MOF-derived (e.g., zeolitic imidazolate framework (ZIF) and UiO-66) M-N x /C catalysts (M = Co, Ni, Fe, W) with a single-atom feature. − Interestingly, the metal coordination environment can be manipulated (e.g., transition from Co–N 4 to Co–N 2 ) by simply tuning the pyrolysis temperature and atmosphere, therefore allowing regulating of the intrinsic activity of a single Co site .…”

Nanofibers Comprising Interconnected Chain‐Like Hollow N‐Doped C Nanocages as 3D Free‐Standing Cathodes for Li–S Batteries with Super‐High Sulfur Content and Lean Electrolyte/Sulfur Ratio

“…At 1000 °C, evaporation of metallic Zn will take place along with the formation of dense carbon shells. [ 35 ] The synergistic effects of volatile zinc metal removal and outward contraction mechanism eventually results in hollow N‐C nanocages. Besides, the heating also resulted in the longitudinal shrinkage of the nanofiber that allows hollow nanocages to pack closely and form chain‐like nanostructure.…”

A high‐performance hybrid supercapacitor electrode based on ZnO/nitrogen‐doped carbon nanohybrid

“…[28] The carbonized ZIFs can produce porous activated carbon-containing pore regimes such as mesopores and micropores similar to activated carbons utilized in industry. [29,30] The material can also be used to synthesize advanced morphologies such as single-shell, double-shell, yolk-shell, yolk-double-shell, [31] and nanoleaves. [32] The material can also be used for the synthesis of heteroatom-doped carbon nanomaterials such as N/P co-doped carbon nanocages (NPCNs), [33] and N/P/S tri-doped hollow carbon nanocapsules (NPS-HCN).…”