Cobalt@Nitrogen‐Doped Porous Carbon Fiber Derived from the Electrospun Fiber of Bimetal–Organic Framework for Highly Active Oxygen Reduction

Abstract

cells. [3] Up to now, Pt-based electrocatalysts have been extensively considered to be the most active ORR electrocatalysts in electrochemical cell reactions. [4][5][6] Nevertheless, crustal rarity, high cost, poor stability, and methanol crossover of Ptbased materials and the sluggish kinetics of cathodic reaction greatly restrict their large-scale practical application. In this connection, a great deal of investigation has been performed based on the study of efficient non-noble metal catalysts, which mainly consists of non-noble metal compounds (e.g., oxides, nitrides, phosphide, and chalcogenides), metal-free catalysts as well as carbonitrides. [7][8][9][10][11] Then, the transition metal carbonitrides (TM-N-C, where TM represents mainly Co, Fe), obtained by carbonization various nitrogen-rich precursor (such as dicyandiamide, melamine, polyaniline, and metal-organic frameworks (MOFs)), have been widely explored to substitute precious metal catalysts because of their high catalytic activity and durability in acid or alkaline electrolyte. [12][13][14][15] In recent years, MOFs have been served as precursors to fabricate the functional nanostructured porous carbon-based electrocatalysts, which gives the credit to their excellent intrinsic characteristics, such as large specific surface area derived from the porosity and the diversity of structure and function stemmed from different metal ions and organic ligands. [16][17][18][19][20][21][22] In particular, Zn-Co bimetallic ZIFs (BMZIFs (ZIF-67 and ZIF-8)) have been extensively employed as precursors to develop efficient Co-based porous nitrogen-doped carbon catalysts, [22][23][24] which attributes to their unique merits. I) Co-N x sites can be easily produced by pyrolysis due to Co metal directly connected to N species. [25,26] II) The larger surface area derived from the pore structure, due to the evaporation of Zn at high temperature. [27,28] III) Uniform N atoms doped into the obtained carbon skeleton after calcination of Zn-ZIF. [29] However, the skeleton of MOFs was generally prone to collapse and aggregate in the pyrolysis process (>700 °C), [17,30] resulting in fewer pore structures, which greatly reduces the electrochemical performance. Therefore, it is urgent and significant to assist the MOFs with quite a few novel substrates (e.g., layered double hydroxides (LDHs), [30,31] graphene, [21] carbon cloth, [32] polyacrylonitrile (PAN) nanofibers, [33] and Te nanowires [29] ) to achieve the The exploitation of high-efficiency, cost-effective, and stable oxygen reduction reaction (ORR) electrocatalysts is extremely critical for energy storage and conversion technology. The transition metal carbonitrides have been investigated as an alternative to precious metal-based catalysts. Here, a series of uniform Co nanoparticles encapsulated in nitrogen-doped porous carbon fibers (Co@N-PCFs for brevity) are designed and synthesized by directly carbonizing the Zn x Co 1-x -zeolitic imidazolate frameworks@polyacrylonitrile (Zn x Co 1-x -ZIFs@PAN) electrospun nanofiber...

Freestanding 1D Hierarchical Porous Fe‐N‐Doped Carbon Nanofibers as Efficient Oxygen Reduction Catalysts for Zn–Air Batteries

“…In the meantime, electrospinning has emerged as an efficient technique for the production of 1D fibrous nanomaterials, which could be performed on a large scale with guaranteed guest homogeneity . Recently, Lan and co‐workers obtained Co nanoparticles embedded in nitrogen‐doped porous carbon fibers derived from Zn, Co‐zeolitic imidazolate frameworks@polyacrylonitrile electrospun nanofibers . Herein, we employed the electrospinning technique and designed a straightforward method to fabricate honeycomb‐like hierarchical Fe‐N‐doped carbon fibers (Fe‐NHCFs) for catalyzing the sluggish rates of ORR and for use as cathodes in practical Zn–air devices.…”

In situ sulfuration synthesis of flexible PAN-CuS “flowering branch” heterostructures as recyclable catalysts for dye degradation

“…It is known that electrospinning is a powerful method to fabricate one-dimensional functional materials with large specic surface-areas, high porosity, good exibility and high stability. [41][42][43] Herein, we elaborately developed stringed "owering branch" PAN-CuS with hierarchical architecture combining brous PAN skeleton and active CuS material. First, we obtained PAN-Cu 2+ composite nanobers from a simple electrospinning method.…”

Binder-Free Nickel Oxide Lamellar Layer Anchored CoOx Nanoparticles on Nickel Foam for Supercapacitor Electrodes

“…According to the charge storage mechanisms of the supercapacitors, they can be classified into two main categories: electric double-layer capacitors (EDLCs) and pseudocapacitors [10][11][12]. Pseudocapacitive materials possess great promise in supercapacitor applications owing to their high theoretical capacitances [13][14][15][16][17][18][19][20][21]. The electrochemical active materials in the electrodes are responsible for charge storage of the devices, while the current collectors take charge in charge transport.…”