ENERGY & FUELS
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2020
·
IF 3.421
Denian Li,Yukun Fan,Haoran Yuan,Lifang Deng,Jizhang Yang,Yong Chen,Bo Luo
An efficient, renewable, and economic electrocatalyst for the oxygen reduction reaction (ORR) is particularly important for next-generation fuel cells and metal–air batteries, and yet this remains a great challenge. In this contribution, we propose a facile and scalable route to the meso–microporous carbon with high specific surface area and enriched pyridinic nitrogen on the basis of direct carbonization of aquatic Scindapsus prior to ammonia injection. The metal-free catalyst proved to be an excellent electrocatalyst for the ORR in alkaline solutions, in terms of the onset potential and limited diffusion current density. It is comparable to a commercial Pt/C catalyst, arising from the large interface and heavy nitrogen doping. In addition to the robust stability against methanol poisoning and long-term operation, this carbonaceous catalyst provides a scalable and economic alternative choice for construction of high-performance ORR-based energy devices at a low cost, which may propel the applications of emerging green energy technologies.
研究领域:
材料科学
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电化学
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能源技术
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可持续化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
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2020
·Vol. 38
·期 10
·1123-1131
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IF 3.826
Liu Yang,Tao Wang,Dongling Wu
Summary of main observation and conclusion Heteroatom-doped carbon materials have been widely used in energy storage and conversion such as supercapacitors and electrocatalysts. In this work, L -asparagine (Asn), an amino acid derivative, has been used as a doping agent to prepare nitrogen- doped reduced graphene oxide gels (N-GAs). The 3D interconnected structure gives rise to the superior electrochemical properties for supercapacitor and electrocatalytic oxygen reduction reaction (ORR). The N-GA-4 (the mass ratio of Asn to graphene oxide (GO) is 4 : 1 by hydrothermal method) electrode shows the capacitance of 291.6 F·g –1 at 0.5 A·g –1 . Meanwhile, the assembled symmetric supercapacitor achieves a maximum energy density of 23.8 Wh· kg –1 when the power density is 451.2 W·kg –1 , and demonstrates an ultralong cycling life that the retention of capacitance is 99.3% after 80000 cycles. What's more, the annealed aerogel N-GA-4-900 exhibits an onset potential ( E onset ) of 0.95 V, half wave potential ( E 1/2 ) of 0.84 V (vs. RHE) and the oxygen reduction current density of 5.5 mA·cm –2 at 0.1 V with nearly four-electron transfer, which are superior to commercial Pt/C. This work offers a new insight into the synthesis and applications of N-GAs materials towards high performance in supercapacitors and ORR.
研究领域:
材料科学
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电化学
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能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 15
·7145-7157
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IF 11.301
Jinling Xue,Yinshi Li,Jue Hu
It remains a major challenge to develop a facile method to prepare non-noble metal electrocatalysts with high activity and durability to drive the sluggish oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs). Herein, a highly efficient bimetallic Zn/Fe@N-doped hierarchical porous carbon (Zn/Fe–N–C) catalyst derived from ZIF-8 and hemin (host–guest) was firstly reported by one-step thermal treatment. Fe2+ spatially separated by using the hemin guest in the ZIF-8 framework and hydrocarbon-branched chains form rich Fe–Nx active sites, and the evaporation of Zn2+ generates a highly porous structure in the Zn/Fe–N–C catalysts. Benefitting from this unique structure and composition, the resulting Zn/Fe2–N–C catalyst exhibits excellent ORR activities in both 0.1 M KOH (onset potential, Eonset = 1.08 V, and half-wave potential, E1/2 = 0.86 V vs. RHE) and 0.5 M H2SO4 media (Eonset = 1.04 V and E1/2 = 0.81 V), which are even comparable to those of the commercial Pt/C catalyst, and ranks among the top reported electrocatalysts. In addition, it also has outstanding long-term durability and good methanol resistance, much better than those of Pt/C in both acidic and alkaline media, which makes it one of the best non-noble alternatives of Pt-based catalysts for ORR electrocatalysis. This work highlights the potential to rationally design and fabricate high-performance ORR catalysts for fuel cell applications.
研究领域:
材料科学
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电化学
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催化
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能源材料
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2021
·Vol. 34
·期 5
·2105410
·
IF 30.849
Leping Yang,Xu Zhang,Lingxiao Yu,Jianhua Hou,Zhen Zhou,Ruitao Lv
Noble-metal-free, durable, and high-efficiency electrocatalysts for oxygen reduction and evolution reaction (ORR/OER) are vital for rechargeable Zn–air batteries (ZABs). Herein, a flexible and free-standing carbon fiber membrane immobilized with atomically dispersed Fe–N 4 /C catalysts (Fe/SNCFs-NH 3 ) is synthesized and used as air cathode for ZABs. The intertwined fibers with hierarchical nanopores facilitate the gas transportation, electrolyte infiltration and electron transfer. The large specific surface area exposes a high concentration of Fe–N 4 /C sites embedded in the carbon matrix. Modulation of local atomic configurations by sulfur doping in Fe/SNCFs-NH 3 catalyst leads to excellent ORR and enhanced OER activities. The as-synthesized Fe/SNCFs-NH 3 catalyst demonstrates a positive half-wave potential of 0.89 V and a small Tafel slope of 70.82 mV dec –1 , outperforming the commercial Pt/C (0.86 V/94.74 mV dec –1 ) and most reported M–N x /C (M = Fe, Co, Ni) catalysts. Experimental characterizations and theoretical calculations uncover the crucial role of S doping in regulating ORR and OER activities. The liquid-state ZABs with Fe/SNCFs-NH 3 catalyst as air cathode deliver a large peak power density of 255.84 mW cm –2 and long-term cycle durability over 1000 h. Solid-state ZAB shows stable cycling at various flat/bent/flat states, demonstrating great prospects in flexible electronic device applications.
研究领域:
材料科学
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电化学
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能源存储
·
电池技术
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催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）