Hollow Loofah‐Like N, O‐Co‐Doped Carbon Tube for Electrocatalysis of Oxygen Reduction

Abstract

Designing a highly active doped‐carbon‐based oxygen reduction reaction (ORR) electrocatalyst with optimal stability is a must if large‐scale implementations of fuel cells are to be realized. Developing controllable doping strategies is essential for achieving highly active catalysts. Herein, a facile doping strategy is developed by designing a precursor material with unique core–shell nanostructure, whereby the Materials Institute Lavoisier (MIL) metal–organic framework (MOF) and polyaniline are core and shell components, and serving as oxygen and nitrogen precursors, respectively. A novel hollow loofah‐like carbon tube (HLCT) catalyst is derived from precursor material with controllable heteroatom‐doping concentrations through modulating the mass ratio of MOF/aniline. The optimal HLCT‐1/2 catalyst, with a MOF/aniline mass ratio of 1/2, exhibits excellent ORR activity and stability in an alkaline medium. Remarkably, the half‐wave potential (0.88 V) and the current density (4.35 mA cm−2) at 0.85 V of HLCT‐1/2 catalyst surpass that of commercial Pt/C. Such superior catalytic properties can be attributed to the high specific surface area and abundant active sites of loofah‐shape carbon tubes. Moreover, the O dopant modulates the content and distribution of N species, leading to the enhanced adsorption strength of oxygen molecules on catalyst surface, promoting the activation of oxygen, and thus achieving higher electrocatalytic activity.

Modulating Metal–Organic Frameworks as Advanced Oxygen Electrocatalysts

“…reported the construction of a hollow loofah‐like carbon tube (HLCT) catalyst with controllable N and O doping. [ 156 ] During this fabrication, Fe‐based MIL‐88b was first synthesized and then employed as template to absorb polyaniline (PANI) through electrostatic interaction in H 2 SO 4 solution. With more and more PANI, a PANI porous shell on the surface of MOF was formed, thus obtaining a MOF@PANI core shell structure.…”

Metal‐organic frameworks‐derived novel nanostructured electrocatalysts for oxygen evolution reaction

“…Hence, it is essential to find the cheaper alternatives that are more common, highly active, and stable 13 . In doing so, a key strategy to retrieve high‐performance OER catalysts hinges upon the availability of electrode materials, including carbon‐based nanomaterials, graphene, and metal oxides/selenides/sulfides 14–24 . Thus far, the scientific community is increasingly interested in porous nanostructure‐based electrode materials, given their high surface‐to‐volume ratio, large and well‐defined pore structure, and even distribution of available active sites.…”

“…13 In doing so, a key strategy to retrieve high-performance OER catalysts hinges upon the availability of electrode materials, including carbon-based nanomaterials, graphene, and metal oxides/selenides/sulfides. [14][15][16][17][18][19][20][21][22][23][24] Thus far, the scientific community is increasingly interested in porous nanostructure-based electrode materials, given their high surface-to-volume ratio, large and well-defined pore structure, and even distribution of available active sites. Nanomaterials with the aforementioned properties are able to accelerate electron transfer and facilitate the mass transport of reactants.…”

Boosting the Performance of Nitrogen‐Doped Mesoporous Carbon Oxygen Electrode with Ultrathin 2D Iron/Cobalt Selenides

“…To further improve the performance of advanced carbon‐based electrocatalysts, certain essential factors should be taken into account adequately, such as abundant and high‐performance active sites for adsorption and/or desorption process, desirable electrical conductivity for fast charge transport, and robust structure for long‐term electrocatalysis. [ 14,15 ] Accordingly, creating abundant active sites by modifying heterogeneous elements on carbon materials with large surface area has been widely adopted. Kim et al.…”