Design Principle of Fe–N–C Electrocatalysts: How to Optimize Multimodal Porous Structures?

Lee, Soo Hong; Kim, Jiheon; Chung, Dong Young; Yoo, Ji Mun; Lee, Hyeon Seok; Kim, Min Jeong; Mun, Bongjin Simon; Kwon, Soon Gu; Sung, Yung‐Eun; Hyeon, Taeghwan

doi:10.1021/jacs.8b11129

Cited by 438 publications

(294 citation statements)

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“…Fe/OES exhibited a more positive onset potential (E O , 1.0 V vs. RHE) and half-wave potential (E 1/2 , 0.85 V vs. RHE) than Fe/BCS and other control samples, indicating the advantages of such an overhang-eave structure with the capability of boosting the mass transport of reactants. [31] The catalytic activity of Fe/OES was comparable to that of Pt/C (E 1/2 , 0.85 V vs. RHE) ( Figure S44) and outperformed those of most of the low-cost electrocatalysts reported to date (Tables S6,S7). Rotating-ring-diskelectrode (RRDE) measurements revealed that the electron transfer number (n) of Fe/OES was about 3.8-4.0 with a low peroxide yield of 1.1-13 % (Figure 3 e).…”

Section: Zuschriftenmentioning

confidence: 79%

Single‐Atom Iron Catalysts on Overhang‐Eave Carbon Cages for High‐Performance Oxygen Reduction Reaction

et al. 2020

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Section: Zuschriftenmentioning

confidence: 79%

Single‐Atom Iron Catalysts on Overhang‐Eave Carbon Cages for High‐Performance Oxygen Reduction Reaction

et al. 2020

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“…To systematically investigate the effect of porous structures on the ORR, Lee et al synthesized three models of N‐doped carbon catalysts ( Figure 7 a), namely, standard (where macro‐, meso‐, and micropores coexisted), meso‐free (where only macro and micropores coexisted), and macro‐free (where only meso‐ and micropores coexisted). [ 105 ] These three model catalysts presented comparable BET surface areas but different pore size distributions (Figure 7b). [ 105 ] To quantitatively analyze the function of pores of different sizes, the electric double‐layer capacitance ( C dl ) of these three model catalysts were measured using two different methods: electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV).…”

Section: Molecular Design Of Sacs With Enhanced Orr Activitymentioning

confidence: 99%

“…[ 105 ] These three model catalysts presented comparable BET surface areas but different pore size distributions (Figure 7b). [ 105 ] To quantitatively analyze the function of pores of different sizes, the electric double‐layer capacitance ( C dl ) of these three model catalysts were measured using two different methods: electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The C dl values obtained using EIS response in the low frequency region ( C dl_ EIS) represented the total surface area that could be wetted by the electrolyte (electrochemically wettable surface area) under static conditions.…”

Section: Molecular Design Of Sacs With Enhanced Orr Activitymentioning

confidence: 99%

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Molecular Design of Single‐Atom Catalysts for Oxygen Reduction Reaction

Wan

Duan

Huang

2020

Advanced Energy Materials

339

210

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His thesis mainly focuses on developing graphene-based single-atom catalysts and the surface engineering of Pt-based nanostructures for energy conversion and storage. Xiangfeng Duan received his Ph.D. in physical chemistry from Harvard University and his B.S. degree in chemistry from the University of Science and Technology of China. His research group at UCLA focuses on developing new material systems for highly efficient energy harvesting, conversion, and storage via the rational design and nanoscale integration of distinct materials. Taking advantage of unique 2D materials, he conducts research on the facile and controllable synthesis of novel single atoms catalysts for energy demanding applications and investigates their structure-activity relationships at atomic level to improve their catalytic activity for future application in real-life devices. Yu Huang received her Ph.D. in physical chemistry from Harvard University and her B.S. degree in chemistry from the University of Science and Technology of China.Her research group at UCLA explores the unique technological opportunities that result from the structure and assembly of nanoscale building blocks. Focusing at phenomena that occur at molecular level, she aims to unravel the fundamental principles that govern the synthesis and assembly of nanoscale material. Moreover, she uses such principles to design nanostructures and nanodevices with unique functions and properties to address critical challenges in electronics, energy science, and biomedicine.

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“…Porous carbon materials have received wide interest because of their attractive physicochemical properties, easy compatibility with other elements, and low cost and toxicity, as well as wide applications in energy storage and conversion, adsorption and catalysis [1][2][3][4][5][6][7]. A well-controlled pore structure is significantly important for these materials in various applications.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Foaming and Activation Strategy to Porous N-Doped Carbon Foams for Supercapacitors and CO2 Capture

et al. 2020

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HIGHLIGHTS• An in situ molecular foaming and activation strategy is designed and investigated for the synthesis of hierarchically porous N-doped carbon foams (HPNCFs).• The prepared HPNCFs possess 3D macropores, uniform micropores and mesopores, ultrahigh surface areas and high N contents and show high performances in supercapacitors and CO 2 capture.ABSTRACT Hierarchically porous carbon materials are promising for energy storage, separation and catalysis. It is desirable but fairly challenging to simultaneously create ultrahigh surface areas, large pore volumes and high N contents in these materials. Herein, we demonstrate a facile acid-base enabled in situ molecular foaming and activation strategy for the synthesis of hierarchically macro-/meso-/microporous N-doped carbon foams (HPNCFs). The key design for the synthesis is the selection of histidine (His) and potassium bicarbonate (PBC) to allow the formation of 3D foam structures by in situ foaming, the PBC/His acid-base reaction to enable a molecular mixing and subsequent a uniform chemical activation, and the stable imidazole moiety in His to sustain high N contents after carbonization. The formation mechanism of the HPNCFs is studied in detail. The prepared HPNCFs possess 3D macroporous frameworks with thin well-graphitized carbon walls, ultrahigh surface areas (up to 3200 m 2 g −1 ), large pore volumes (up to 2.0 cm 3 g −1 ), high micropore volumes (up to 0.67 cm 3 g −1 ), narrowly distributed micropores and mesopores and high N contents (up to 14.6 wt%) with pyrrolic N as the predominant N site. The HPNCFs are promising for supercapacitors with high specific capacitances (185-240 F g −1 ), good rate capability and excellent stability. They are also excellent for CO 2 capture with a high adsorption capacity (~ 4.13 mmol g −1 ), a large isosteric heat of adsorption (26.5 kJ mol −1 ) and an excellent CO 2 /N 2 selectivity (~ 24). on the two isotherms wherein the adsorption capacities are the same.

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Design Principle of Fe–N–C Electrocatalysts: How to Optimize Multimodal Porous Structures?

Cited by 438 publications

References 50 publications

Single‐Atom Iron Catalysts on Overhang‐Eave Carbon Cages for High‐Performance Oxygen Reduction Reaction

Single‐Atom Iron Catalysts on Overhang‐Eave Carbon Cages for High‐Performance Oxygen Reduction Reaction

Molecular Design of Single‐Atom Catalysts for Oxygen Reduction Reaction

A Molecular Foaming and Activation Strategy to Porous N-Doped Carbon Foams for Supercapacitors and CO2 Capture

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