Nanochannel-Controlled Synthesis of Ultrahigh Nitrogen-Doping Efficiency on Mesoporous Fe/N/C Catalysts for Oxygen Reduction Reaction

Abstract

Designing appropriate methods to effectively enhance nitrogen-doping efficiency and active-site density is essential to boost the oxygen reduction reaction (ORR) activity of non-platinum Fe/N/C-type electrocatalysts. Here, we propose a facile and effective strategy to design a mesopore-structured Fe/N/C catalyst for the ORR with ultrahigh BET surface area and outstanding conductivity via nanochannels of molecular sieve-confined pyrolysis of Fe 2+ ions coordinated with 2,4,6-tri(2-pyridyl)-1,3,5-triazine complexes as a novel precursor with the stable coordination effect. Combining the nanochannel-confined effect with the stable coordination effect can synergistically improve the thermal stability and stabilize the nitrogen-enriched active sites, and help to control the loss of active N atoms during pyrolysis process and to further obtain a high active-site density for enhancing the ORR activity. The asprepared Fe/N/C electrocatalyst has exhibited excellent catalytic activity with an onset potential of~0.841 V (versus RHE) closely approaching the Pt/C catalyst and high long-term stability in alkaline electrolyte. Besides, low-hydrogen peroxide yield (< 6.5%) and high electron transfer number (3.88-3.94) can be found on this catalyst, indicating that it is a valuable substitute for traditional Pt/C catalysts. This work paves a new way to design high-performance Fe/ N/C electrocatalysts and deepens the understanding of active site and ORR catalysis mechanism.

Catalytic confinement effects in nanochannels: from biological synthesis to chemical engineering

“…4b ). 79 They found that the CCE in the nanochannels boosted thermal stability and improved the stability of nitrogen-enriched active sites. In another research study on the HER, Tang et al developed novel electrocatalysts with hierarchical MoS 2 /CoS 2 nanochannel arrays ( Fig.…”

Simply prepared electrocatalyst of CoFe alloy and nitrogen-doped carbon with multi-dimensional structure and high performance for rechargeable zinc-air battery

“…The intensity of Zn 2p XPS spectra is weak (figure S5c), which is consistent with its low content as shown in figure S3. The N 1s spectrum of CoFe-NC in figure 2(c) displays, besides graphite nitrogen (401.3 eV) and oxidation nitrogen (404.1 eV), the important active sites of pyridine nitrogen (398.5 eV) and Co/Fe-N x (399.8 eV), which contributes much to ORR performance [36,[44][45][46]. The disappearance of the pyrrole nitrogen peak may be because the content is too small [47].…”

An efficient bifunctional electrocatalyst of phosphorous carbon co-doped MOFs

“…In recent years, the rapidly growing demand for energy sustainable development has drawn great interest among researchers in the field of electrochemical energy conversion and energy storage technologies [1][2][3]. In order to meet the demand for energy conversion and distribution, investigating an alternative non-precious metal electrode material with well-designed structure, controlled chemical and excellent electrochemical performance will be our constant pursuit [4][5][6][7]. The oxygen evolution reaction (OER) which is the anodic reaction of energy storage and conversion can be applied to solar cells, electrolysis cells, rechargeable metal-air cells and so on.…”

“…Meanwhile, carbon nanomaterials due to their high stability, high conductivity and controllable morphology become extremely attractive and have been applied in many electrochemical devices, such as polymer fuel cell catalysts [2,20]. In addition, carbon nanomaterials doped with heterogenous elements can greatly improve the catalytic activity and the surface chemistry area [4,13,[20][21][22][23][24][25]. It has been found that carbon materials composites not only have synergistic catalysis in catalytic activity but also have a synergistic effect in direct catalysis of ORR, such as hetero-doped carbon materials [26,27].…”