3D polymer hydrogel for high-performance atomic iron-rich catalysts for oxygen reduction in acidic media

Qiao, Zhi; Zhang, Hanguang; Karakalos, Stavros; Hwang, Sooyeon; Xue, Jing; Chen, Mengjie; Su, Dong; Wu, Gang

doi:10.1016/j.apcatb.2017.08.008

Cited by 115 publications

(55 citation statements)

References 95 publications

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“…Different from the physical mixture of N‐, C‐, and metal‐containing small molecules, the MOFs skeleton allows the prearrangement of N, C, and metal elements at the molecular level. This skeleton can then act as a template for the formation of ordered carbonized derivatives with uniformly dispersed SACs sites . Pyrolysis of Zn‐based bimetallic MOFs (usually Co, Fe, Ni, etc.…”

Section: Innovative Synthesis Of Sacs On Carbon Substratesmentioning

confidence: 99%

“…The studied hard templates include SiO 2 nanospheres, branched SiO 2 nanoaggregates, ordered mesoporous SiO 2 , and MgO . The soft templates involved Na 2 CO 3 , KCl, hydrogels, and a self‐assembled FeCl 3 layer . For instance, Wan et al reported the synthesis of atomically dispersed FeN 4 on concave‐shaped octahedral carbon cages from SiO 2 coated ZIF‐8 precursors .…”

Section: Innovative Synthesis Of Sacs On Carbon Substratesmentioning

confidence: 99%

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Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Zhu

Sokolowski

Song

et al. 2019

Advanced Energy Materials

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Carbon‐based heteroatom‐coordinated single‐atom catalysts (SACs) are promising candidates for energy‐related electrocatalysts because of their low‐cost, tunable catalytic activity/selectivity, and relatively homogeneous morphologies. Unique interactions between single metal sites and their surrounding coordination environments play a significant role in modulating the electronic structure of the metal centers, leading to unusual scaling relationships, new reaction mechanisms, and improved catalytic performance. This review summarizes recent advancements in engineering of the local coordination environment of SACs for improved electrocatalytic performance for several crucial energy‐convention electrochemical reactions: oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, CO2 reduction reaction, and nitrogen reduction reaction. Various engineering strategies including heteroatom‐doping, changing the location of SACs on their support, introducing external ligands, and constructing dual metal sites are comprehensively discussed. The controllable synthetic methods and the activity enhancement mechanism of state‐of‐the‐art SACs are also highlighted. Recent achievements in the electronic modification of SACs will provide an understanding of the structure–activity relationship for the rational design of advanced electrocatalysts.

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Section: Innovative Synthesis Of Sacs On Carbon Substratesmentioning

confidence: 99%

Section: Innovative Synthesis Of Sacs On Carbon Substratesmentioning

confidence: 99%

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Zhu

Sokolowski

Song

et al. 2019

Advanced Energy Materials

Self Cite

294

240

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“…Recently, tremendous efforts have been made to explore the most promising transition metal and nitrogen co‐doped carbon (M‐N‐C, M: Fe, Co, or/and Mn) catalysts, in which atomically dispersed MN 4 sites are likely the active sites for the ORR in acidic electrolytes. Despite recent advances in activity and stability, the synthesis of these materials is still limited to traditional co‐pyrolysis of metal, nitrogen, and carbon sources using templated (carbon black and silica) and self‐templated (MOFs and hydrogels) precursors . This traditional synthesis concept has primarily limited the improvement of catalyst performance due to poor control of the catalyst morphology and the local structure of the active sites.…”

Section: Introductionmentioning

confidence: 99%

Thermally Driven Structure and Performance Evolution of Atomically Dispersed FeN₄ Sites for Oxygen Reduction

et al. 2019

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FeN4 moieties embedded in partially graphitized carbon are the most efficient platinum group metal free active sites for the oxygen reduction reaction in acidic proton‐exchange membrane fuel cells. However, their formation mechanisms have remained elusive for decades because the Fe−N bond formation process always convolutes with uncontrolled carbonization and nitrogen doping during high‐temperature treatment. Here, we elucidate the FeN4 site formation mechanisms through hosting Fe ions into a nitrogen‐doped carbon followed by a controlled thermal activation. Among the studied hosts, the ZIF‐8‐derived nitrogen‐doped carbon is an ideal model with well‐defined nitrogen doping and porosity. This approach is able to deconvolute Fe−N bond formation from complex carbonization and nitrogen doping, which correlates Fe−N bond properties with the activity and stability of FeN4 sites as a function of the thermal activation temperature.

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“…During the preparation of NiFeNSC, the Ni 2+ and Fe 3+ were strongly anchored and homogeneously dispersed on the CNF surface owing to the chemical adsorption and physical interaction with CNF. The subsequent in situ thermal activation directly converted the hydrogel into interconnecting carbon networks bearing active sites . The CNF being precursors along with the unique 3D network framework was expected to as a green dispersant to avoid the aggregation of Ni and Fe, and provided great benefits to increase active sites.…”

Section: Resultsmentioning

confidence: 99%

Natural‐Cellulose‐Nanofibril‐Tailored NiFe Nanoparticles for Efficient Oxygen Evolution Reaction

Tian

Liu

et al. 2019

ChemElectroChem

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High performance, resource abundance, and environmental friendliness have been raising as major challenges for the next‐generation of affordable and sustainable electrocatalysts. Herein, natural cellulose nanofibrils (CNFs) with abundant carboxyls and hydroxyls were employed to tailor NiFe catalysts (NiFeNSC) for the efficient oxygen evolution reaction (OER). Benefiting from the introduction of CNF, the NiFe metal ions were homogeneously dispersed on the CNF surface and exhibited a smaller particle size. Additionally, the surface area was 3.17 times larger and the surface wettability was significantly improved. By integrating the active NiFe nanoparticles with doped CNF, the overpotential of synthesized NiFeNSC catalyst was decreased from 370 mV to 244 mV to deliver a current density of 10 mA cm−2, and exhibited a small Tafel slope of 43.3 mV dec−1 in 1.0 M KOH electrolyte. Impressively, the NiFeNSC displayed excellent long‐term stability, which was only 38 mV increased over 24 h chronopotentiometry measurement, outperforming the catalyst without CNF (NiFeNS) and commercial RuO2 catalyst remarkably. The present results demonstrate a new avenue for designing resource abundant and sustainable electrocatalysts, providing a novel strategy to replace the fossil‐involved nanocarbon.

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3D polymer hydrogel for high-performance atomic iron-rich catalysts for oxygen reduction in acidic media

Cited by 115 publications

References 95 publications

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Thermally Driven Structure and Performance Evolution of Atomically Dispersed FeN₄ Sites for Oxygen Reduction

Natural‐Cellulose‐Nanofibril‐Tailored NiFe Nanoparticles for Efficient Oxygen Evolution Reaction

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3D polymer hydrogel for high-performance atomic iron-rich catalysts for oxygen reduction in acidic media

Cited by 115 publications

References 95 publications

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Engineering Local Coordination Environments of Atomically Dispersed and Heteroatom‐Coordinated Single Metal Site Electrocatalysts for Clean Energy‐Conversion

Thermally Driven Structure and Performance Evolution of Atomically Dispersed FeN4 Sites for Oxygen Reduction

Natural‐Cellulose‐Nanofibril‐Tailored NiFe Nanoparticles for Efficient Oxygen Evolution Reaction

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Thermally Driven Structure and Performance Evolution of Atomically Dispersed FeN₄ Sites for Oxygen Reduction