Carbon nanotubes anchored onto hollow carbon for efficient oxygen reduction

Abstract

The rational design and facile construction of non-noble metal-based electrocatalysts for efficient oxygen reduction reaction (ORR) remain a challenge for the development of clean energy conversion devices. Herein, we synthesized a new type of hierarchical hollow carbon nanomaterials through one-step pyrolysis on bimetallic ZIF-Zn/Co precursors. The obtained hollow N-doped carbon composites, denoted as HNCT-CNTs, are enriched with Co-N x sites and in-situ formed multi-walled carbon nanotubes (CNTs). Theoretical and experimental studies confirmed that the obtained HNCT-CNT exhibits excellent ORR catalytic activity with a reduced energy barrier for ORR intermediates. Owing to these advantages, the optimal catalyst shows an excellent half-wave potential of 0.85 V, a limiting current density up to 6.36 mA cm −2 , a Tafel slope of 58.2 mV dec −1 , and robust stability. Furthermore, the assembled Zn-air battery based on HNCT-CNT also displays an open circuit voltage of 1.49 V and a satisfactory power density of 116.56 mW cm −2 . This template-directed preparation method opens up an interesting and efficient route to fabricate highly active non-noble metaldoped carbon nanomaterials for a wide range of electrochemical energy applications.

Double‐Carbon‐Layer Core–Shell Complex Sulfides Derived from Bimetallic Metal–Organic Frameworks for Li‐/Na‐Ion Battery Storage

“…The structure of the formed ZnS/CoS 2 -C@NC-12 remains after the material undergoes vapor-phase vulcanization. There are still carbon nanotubes on the surface of the core-shell structure (Figure 2a) possibly because the cobalt in the precursor will be used as a kind of catalyst to facilitate the carbon nanotube's growth [11,12,19] under such high carbonization temperature for much longer time than those for ZnS/CoS 2 @C-x. It can be seen from the XRD test results that the characteristic peaks of the ZnS/CoS 2 -C@NC-12 material correspond to the peaks of CoS 2 and ZnS, indicating that the Co and Zn elements in the Zn-Co-ZIF@PDA-12 material are converted into CoS 2 and ZnS (Figure 2c).…”

“…However, some MOF-derived composites still suffer from structural instability and insufficient electrical conductivity. To overcome these problems, combining derivatives with conductive carbon materials [19] is an effective strategy. [20,21] In this work, we used bimetallic MOF (Zn-Co-ZIF) as the precursor, coated with dopamine hydrochloride, and prepared ZnS/CoS 2 -C@NC with double-carbon-layer core-shell structure through high-temperature carbonization and gas-phase sulfidation.…”

“…However, some MOF‐derived composites still suffer from structural instability and insufficient electrical conductivity. To overcome these problems, combining derivatives with conductive carbon materials [ 19 ] is an effective strategy. [ 20,21 ]…”

Design of Uniform Hollow Carbon Nanoarchitectures: Different Capacitive Deionization between the Hollow Shell Thickness and Cavity Size

“…[1][2][3] This extensive application can be credited to the distinct characteristics of carbon-based materials DOI: 10.1002/advs.202206960 including good conductivity, favorable chemical and thermal stability, intrinsic hydrophobicity, and easy surface modification. [4][5][6] Among them, hollow carbon materials (HCs) consist of carbon shells and internal cavities, which possess additional features, such as accessible internal cavity, porous carbon shells, high surface area, and adjustable porosity. [7][8][9] In particular, the hollow cavity can offer a high specific surface area together with reduced charge and mass diffusion distance and the mesopores on the shell can provide diffusion channels for rapid ion movement.…”

Study on the microscopic mechanism of adsorption and diffusion of hydrocarbon oil drops on coal surface using molecular dynamics simulations

“…The addition of oleic acid enhanced the adsorption of its mixture to the coal surface, but slowed down the diffusion rate, which improved the flotation efficiency [18]. However, all of the above are studied experimentally, and in recent years, with the gradual rise of molecular simulation, it has been widely used in chemistry, physics, materials, and biology [19][20][21][22]. Molecular simulations allow the study of chemical reactions and conformational changes of substances at different spatial scales of micro-, nano-, and mesoscopic scales, which can overcome the problems of insufficient funding for experiments and also enable the dynamic evolution of the simulated system [23][24][25].…”