Templating Synthesis of Mesoporous Fe₃C-Encapsulated Fe–N-Doped Carbon Hollow Nanospindles for Electrocatalysis

Abstract

Developing cost-efficient alternatives to the noble metal catalysts toward oxygen reduction reaction (ORR) has attracted much attention. Herein, a kind of mesoporous hollow spindlelike Fe-N-C electrocatalysts with iron carbide nanoparticles encased in the N-doped graphitic layers has been synthesized by a novel "reactive hard template" strategy through the Fe-assisted polymerization of dopamine on the FeO cores and the following calcinations. The FeO nanospindles not only as the hard template guide the formation of well-defined shape and structure of the catalyst but also as the reactive template provide Fe reservoir to generate FeC nanoparticles in the catalyst during the thermochemical process. The superiority in accessible active sites of Fe-N species, FeC nanoparticles in graphenelike layers, and highly mesoporous hollow structure enables the catalysts to exhibit excellent ORR performances including high catalytic activity, outstanding long-term cycling stability, and good tolerance to methanol.

Efficient Oxygen Reduction Catalysts of Porous Carbon Nanostructures Decorated with Transition Metal Species

“…c) Schematic illustration for the fabrication process of the hollow catalyst. Reproduced with permission 31. Copyright 2018, ACS.…”

“…Furthermore, the metal species can also be doped into the carbon matrix, leaving little residue and simplifying the removal procedure. For instance, Fe 2 O 3 nanospindles have been researched as the hard template for forming well‐defined shape and structure of the resultant catalyst, where the iron ions can promote the polymerization of dopamine and boost the graphitization of the carbon sources as shown in Figure 1c 31. Besides, the Fe 2 O 3 nanospindle templates can also provide iron resources to generate iron carbide nanoparticles, serving as the active sites for ORR.…”

Template‐free synthesis of novel hollow carbon nanospheres with dual active sites as catalyst for fuel cell cathode to improve oxygen reduction reaction performances

“…The specific surface analysis and pore size distribution are evaluated, and their results are exhibited in Figure 4B. 45 The high-resolution C1s spectrum of the HCN-FNFCG-650 are decomposed into five different peaks ( Figure 5C), centered at about 284.6, 285.3, 286.6, 288.1, and 289.3 eV, which can be corresponded to the C═C, C─C, C─N, C─O, and O═C─O groups. By contrast, the HCN-FNFCG-650 with higher surface areas (S BET and S BJH are up to198.25 m 2 g −1 and 99.879 m 2 g −1 ) has larger pore volume (0.4012 cm 3 g −1 ), contrasted with samples of HCN-FNFCG-450 (92.27 m 2 g −1 , 77.532 m 2 g −1 , and 0.1782 cm 3 g −1 ) and HCN-FNFCG-850 (89.653 m 2 g −1 , 68.846 m 2 g −1 , and 0.1298 cm 3 g −1 ).…”

Importance of Electrocatalyst Morphology for the Oxygen Reduction Reaction

“…The hard‐templating method is an effective method for the synthesis of 1D M−N−C electrocatalysts. Recently, Yu's group used the Fe 2 O 3 nanorod as both the template and the Fe source to prepare the Fe−N−C nanorod . The polydopamine (PDA) was selected as the sources of N and C. Wang et al.…”