Nanowire‐Templated Synthesis of FeN_x‐Decorated Carbon Nanotubes as Highly Efficient, Universal‐pH, Oxygen Reduction Reaction Catalysts

Abstract

It is of increasing importance to develop highly active and economical oxygen reduction reaction (ORR) electrocatalysts, which have great significance for the large‐scale implementation of various energy conversion systems, including metal–air batteries and fuel cells. Herein, a novel method to synthesize FeNx‐decorated carbon nanotubes as a high‐efficiency ORR catalyst, by utilizing ZnO nanowires as a sacrificial template and a Fe–polydopamine complex as metal and carbon sources, is reported. The obtained catalyst shows great potential for replacing Pt/C as the ORR catalyst under various pH conditions, from alkaline to acidic electrolytes. The high conductivity, large surface area of the carbon nanotube, and highly active FeNx species contributed greatly to the high performance of the catalyst. The work presented herein paves a new way for the synthesis of 1D porous nanomaterials for a broad range of energy‐related applications.

Metal–Nitrogen–Carbon Catalysts of Specifically Coordinated Configurations toward Typical Electrochemical Redox Reactions

“…[42][43][44][45][46] Despite the broad prospects of M-N-C catalysis and progress being made over the past decade in catalytic applications of ORR OER, HER, and CO2RR, the precise control of coordination configuration of the metal with nitrogen still remains a major challenge in the in-depth exploration of the catalytic mechanism of the M-N-C catalysts. [47][48][49][50][51][52][53][54][55][56][57] In fact, the coordination number x in M-N x plays an important role in determining the catalytic activity by tailoring the charge distribution of the metal active centers. The x value can be tuned from 1 to 6, corresponding to the configurations of MN 1 , MN 2 , MN 3 , MN 4 , MN 5 , and MN 6 , respectively.…”

Confined Synthesis of N, P Co–Doped 3D Hierarchical Carbons as High‐Efficiency Oxygen Reduction Reaction Catalysts for Zn–Air Battery

“…Doping heteroatoms into carbon framework can not only induced redistribution of atomic charge density to facilitate O 2 adsorption on the catalysts, but also could create more defects and chemical bonding for O 2 adsorption and dissociation . Generally, N is the most widely utilized heteroatom for doping due to its similar atomic radius and different electronegativity with carbon . However, in most cases, the performance of the carbon doped only by N atoms is still inferior, especially compared with precious Pt‐based catalysts.…”

“…[11][12] Generally, N is the most widely utilized heteroatom for doping due to its similar atomic radius and different electronegativity with carbon. [13][14] However, in most cases, the performance of the carbon doped only by N atoms is still inferior, especially compared with precious Ptbased catalysts. In contrast, multiple heteroatoms co-doping can further verify the electronic structures and polarities of the catalysts, and synergistic effect of different heteroatoms are observed.…”

FeNx/FeSx-Anchored Carbon Sheet–Carbon Nanotube Composite Electrocatalysts for Oxygen Reduction

“…Ma et al prepared FeN x -decorated carbon nanotubes at high temperature through the sacrificial template method, which displays catalytic activity in both the acidic and basic media. 23 Among the noble-metal-free ORR catalysts which display performance in the acidic pH conditions, the systems based on Fe−N x moieties embedded in the carbon matrix are the most versatile ones with activity comparable to the state-of-the-art Pt/C catalyst. 24−27 Recently, Fe−S x engrafted carbon is also reported to be displaying activity comparable to Pt/C in the acidic medium.…”

“…However, the ORR performance of such systems is found to be highly sensitive to the pH of the electrolytes, and the majority are reported to be more active in basic pH conditions. Ma et al prepared FeN x -decorated carbon nanotubes at high temperature through the sacrificial template method, which displays catalytic activity in both the acidic and basic media …”