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Gelatin-derived sustainable carbon-based functional materials for energy conversion and storage with controllability of structure and component.

Wang ZL, Xu D, Zhong HX, Wang J, Meng FL, Zhang XB - Sci Adv (2015)

Bottom Line: The catalysts demonstrate higher catalytic activity and better durability for oxygen reduction than precious Pt/C catalysts.The oxygen reduction reaction (ORR) activity correlates well with the surface area, porosity, and the content of active Fe-N x /C (D1 + D3) species.The synthetic approach and the proposed mechanism open new avenues for the development of sustainable carbon-based functional materials.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.

ABSTRACT
Nonprecious carbon catalysts and electrodes are vital components in energy conversion and storage systems. Despite recent progress, controllable synthesis of carbon functional materials is still a great challenge. We report a novel strategy to prepare simultaneously Fe-N-C catalysts and Fe3O4/N-doped carbon hybrids based on the sol-gel chemistry of gelatin and iron with controllability of structure and component. The catalysts demonstrate higher catalytic activity and better durability for oxygen reduction than precious Pt/C catalysts. The active sites of FeN4/C (D1) and N-FeN2+2/C (D3) are identified by Mössbauer spectroscopy, and most of the Fe ions are converted into D1 or D3 species. The oxygen reduction reaction (ORR) activity correlates well with the surface area, porosity, and the content of active Fe-N x /C (D1 + D3) species. As an anode material for lithium storage, Fe3O4/carbon hybrids exhibit superior rate capability and excellent cycling performance. The synthetic approach and the proposed mechanism open new avenues for the development of sustainable carbon-based functional materials.

No MeSH data available.


(A and B) TEM (A) and HRTEM (B) images of Fe3O4@AGC electrode material. (C and D) Comparison of rate capabilities (C) and cycle performance (D) of Fe3O4@AGC and bare Fe3O4.
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Figure 5: (A and B) TEM (A) and HRTEM (B) images of Fe3O4@AGC electrode material. (C and D) Comparison of rate capabilities (C) and cycle performance (D) of Fe3O4@AGC and bare Fe3O4.

Mentions: Besides the highly active Fe-N-C catalysts, the sol-gel strategy of gelatin can also produce excellent Fe3O4/N-doped carbon hybrids for LIBs. Figure 5A shows the as-prepared Fe3O4/N-doped carbon hybrid (Fe3O4@AGC) from the composite gel after high-temperature treatment. It can be observed that Fe3O4 nanoparticles are uniformly confined in three-dimensional frameworks. The high-resolution TEM image in Fig. 5B shows the interfacial structure between carbon matrix and the Fe3O4 particle. Thermogravimetric analysis of Fe3O4@AGC reveals that the weight fraction of Fe3O4 in the composites is 78%. It is noted that, keeping the hybrid structure, the content of Fe3O4 can be variable from 70 to 94% by adjusting the ratio of metal salt and gelatin as shown in figs. S17 and S18. As anode materials of LIBs, Fe3O4@AGC manifests an exceptionally high rate capability compared with bare Fe3O4 (Fig. 5C). For example, at a current density of 5000 mA g−1, Fe3O4@AGC still delivers a favorable capacity of 260 mAh g−1, whereas bare Fe3O4 only exhibits a capacity of 45 mAh g−1. Moreover, when the current rate is returned to 100 mA g−1, the stable high capacity of Fe3O4@AGC (820 mAh g−1) is resumed. Except for the rate capability, the cycling performance of Fe3O4@AGC is also superior to that of bare Fe3O4 particles (Fig. 5D). Although the initial capacities of both samples are similar, the gap of retentions is great. After 150 cycles at 500 mA g−1, the capacity of Fe3O4@AGC (660 mAh g−1) is four times more than that of bare Fe3O4 particles (150 mAh g−1). Although the performance of Fe3O4@AGC is similar to that of complex Fe3O4/graphene composites (18, 20, 52), the preparation method of the former is more facile and sustainable than that of the latter, which makes Fe3O4@AGC more favorable for large-scale applications.


Gelatin-derived sustainable carbon-based functional materials for energy conversion and storage with controllability of structure and component.

Wang ZL, Xu D, Zhong HX, Wang J, Meng FL, Zhang XB - Sci Adv (2015)

(A and B) TEM (A) and HRTEM (B) images of Fe3O4@AGC electrode material. (C and D) Comparison of rate capabilities (C) and cycle performance (D) of Fe3O4@AGC and bare Fe3O4.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 5: (A and B) TEM (A) and HRTEM (B) images of Fe3O4@AGC electrode material. (C and D) Comparison of rate capabilities (C) and cycle performance (D) of Fe3O4@AGC and bare Fe3O4.
Mentions: Besides the highly active Fe-N-C catalysts, the sol-gel strategy of gelatin can also produce excellent Fe3O4/N-doped carbon hybrids for LIBs. Figure 5A shows the as-prepared Fe3O4/N-doped carbon hybrid (Fe3O4@AGC) from the composite gel after high-temperature treatment. It can be observed that Fe3O4 nanoparticles are uniformly confined in three-dimensional frameworks. The high-resolution TEM image in Fig. 5B shows the interfacial structure between carbon matrix and the Fe3O4 particle. Thermogravimetric analysis of Fe3O4@AGC reveals that the weight fraction of Fe3O4 in the composites is 78%. It is noted that, keeping the hybrid structure, the content of Fe3O4 can be variable from 70 to 94% by adjusting the ratio of metal salt and gelatin as shown in figs. S17 and S18. As anode materials of LIBs, Fe3O4@AGC manifests an exceptionally high rate capability compared with bare Fe3O4 (Fig. 5C). For example, at a current density of 5000 mA g−1, Fe3O4@AGC still delivers a favorable capacity of 260 mAh g−1, whereas bare Fe3O4 only exhibits a capacity of 45 mAh g−1. Moreover, when the current rate is returned to 100 mA g−1, the stable high capacity of Fe3O4@AGC (820 mAh g−1) is resumed. Except for the rate capability, the cycling performance of Fe3O4@AGC is also superior to that of bare Fe3O4 particles (Fig. 5D). Although the initial capacities of both samples are similar, the gap of retentions is great. After 150 cycles at 500 mA g−1, the capacity of Fe3O4@AGC (660 mAh g−1) is four times more than that of bare Fe3O4 particles (150 mAh g−1). Although the performance of Fe3O4@AGC is similar to that of complex Fe3O4/graphene composites (18, 20, 52), the preparation method of the former is more facile and sustainable than that of the latter, which makes Fe3O4@AGC more favorable for large-scale applications.

Bottom Line: The catalysts demonstrate higher catalytic activity and better durability for oxygen reduction than precious Pt/C catalysts.The oxygen reduction reaction (ORR) activity correlates well with the surface area, porosity, and the content of active Fe-N x /C (D1 + D3) species.The synthetic approach and the proposed mechanism open new avenues for the development of sustainable carbon-based functional materials.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.

ABSTRACT
Nonprecious carbon catalysts and electrodes are vital components in energy conversion and storage systems. Despite recent progress, controllable synthesis of carbon functional materials is still a great challenge. We report a novel strategy to prepare simultaneously Fe-N-C catalysts and Fe3O4/N-doped carbon hybrids based on the sol-gel chemistry of gelatin and iron with controllability of structure and component. The catalysts demonstrate higher catalytic activity and better durability for oxygen reduction than precious Pt/C catalysts. The active sites of FeN4/C (D1) and N-FeN2+2/C (D3) are identified by Mössbauer spectroscopy, and most of the Fe ions are converted into D1 or D3 species. The oxygen reduction reaction (ORR) activity correlates well with the surface area, porosity, and the content of active Fe-N x /C (D1 + D3) species. As an anode material for lithium storage, Fe3O4/carbon hybrids exhibit superior rate capability and excellent cycling performance. The synthetic approach and the proposed mechanism open new avenues for the development of sustainable carbon-based functional materials.

No MeSH data available.