Soft template-directed interlayer confinement synthesis of a Fe-Co dual single-atom catalyst for Zn-
Explore the source record for details and available documents.
Wu, Yunyan↗
SEARCH · Search NASA
Results for “Fe single atom”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Fe-N-C single-atom nanozyme for ultrasensitive, on-site and multiplex detection of mycotoxins using
Explore the source record for details and available documents.
Cai, Xinfa↗
An Ion-Imprinting Derived Strategy to Synthesize Single-Atom Iron Electrocatalysts for Oxygen Reduction
Carbon-based single-atom catalysts (CSACs) have recently received extensive attention in catalysis research. However, the preparation process of CSACs involves a high-temperature treatment, during which metal atoms are mobile and aggregated into nanoparticles, detrimental to the catalytic performance. Herein, an ion-imprinting derived strategy is proposed to synthesize CSACs, in which isolated metal-nitrogen-carbon (Me-N 4 -C x ) moiety covalently binds oxygen atoms in Si-based molecular sieve frameworks. Such a feature makes Me-N 4 -C x moiety well protected/confined during the heat treatment, resulting in the final material enriched with single-atom metal active sites. As a proof of concept, a single-atom Fe-N-C catalyst is synthesized by using this ion-imprinting derived strategy. Finally, experimental results and theoretical calculations demonstrate high concentration of single FeN 4 active sites distributed in this catalyst, resulting in an outstanding oxygen reduction reaction (ORR) performance with a half-wave potential of 0.908 V in alkaline media.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Photosynthesis of a Photocatalyst: Single Atom Platinum Captured and Stabilized by an Iron(III) Engineered Defect
Single atom (SA), noble metal catalysts are of interest due to high projected catalytic activity while minimizing cost. Common issues facing many synthesis methodologies include complicated processes, low yields of SA product, and production of mixtures of SA and nanoparticles (NPs). Herein we report a simple, room-temperature synthesis of single Pt-atom decorated, anatase Fe-doped TiO 2 particles that leverages the Fe dopant as an engineered defect site to photodeposit and stabilize atomically dispersed Pt. Both particle morphology and Fe dopant location are based on thermodynamic principles (Gibbs-Wulff construction). CO-DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) reveals absence of bridge-bonded CO signal, confirming atomically dispersed Pt. XAS (x-ray absorption spectroscopy) of both Pt and Fe indicates Fe-O-Pt bonding that persists through catalytic cycling. Mass balance indicates Pt loading on single particles is 2.5 wt% Pt; single Pt-atom decorated nanoparticle yield is 17%. Pt containing particles show more than an order-of-magnitude increased photo-oxidation efficiency relative to particles containing only Fe. High single-atom-Pt yield, ease of synthesis, and high catalytic activity demonstrate the utility and promise of this method. In conclusion, the principles of this photodeposition synthesis allow for its generalizability towards other SA metals of catalytic interest.
36 MATERIALS SCIENCE↗
Materials Data on NpFe(OF2)3 by Materials Project
NpFe(OF2)3 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Np sites. In the first Np site, Np is bonded to one O and six F atoms to form distorted NpOF6 pentagonal bipyramids that share corners with four equivalent FeO2F4 octahedra. The corner-sharing octahedra tilt angles range from 33–37°. The Np–O bond length is 1.80 Å. There are a spread of Np–F bond distances ranging from 2.04–2.18 Å. In the second Np site, Np is bonded to one O and six F atoms to form distorted NpOF6 pentagonal bipyramids that share corners with four equivalent FeO2F4 octahedra. The corner-sharing octahedra tilt angles range from 33–37°. The Np–O bond length is 1.80 Å. There are a spread of Np–F bond distances ranging from 2.04–2.18 Å. Fe is bonded to two O and four F atoms to form FeO2F4 octahedra that share corners with four NpOF6 pentagonal bipyramids. Both Fe–O bond lengths are 1.67 Å. There are two shorter (2.07 Å) and two longer (2.20 Å) Fe–F bond lengths. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Np atom. In the second O site, O is bonded in a single-bond geometry to one Fe atom. In the third O site, O is bonded in a single-bond geometry to one Np atom. In the fourth O site, O is bonded in a single-bond geometry to one Fe atom. There are six inequivalent F sites. In the first F site, F is bonded in a bent 150 degrees geometry to one Np and one Fe atom. In the second F site, F is bonded in a bent 150 degrees geometry to one Np and one Fe atom. In the third F site, F is bonded in a bent 150 degrees geometry to one Np and one Fe atom. In the fourth F site, F is bonded in a single-bond geometry to one Np atom. In the fifth F site, F is bonded in a bent 150 degrees geometry to one Np and one Fe atom. In the sixth F site, F is bonded in a single-bond geometry to one Np atom.
36 MATERIALS SCIENCE↗
Materials Data on Cr3Fe2O15 by Materials Project
Cr2FeO8CrFeO7 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two CrFeO7 ribbons oriented in the (0, 1, 0) direction and one Cr2FeO8 sheet oriented in the (0, 0, 1) direction. In each CrFeO7 ribbon, Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with two equivalent FeO5 trigonal bipyramids. There are a spread of Cr–O bond distances ranging from 1.60–1.80 Å. Fe is bonded to five O atoms to form FeO5 trigonal bipyramids that share corners with two equivalent CrO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.65–1.90 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Fe atom. In the second O site, O is bonded in a single-bond geometry to one Fe atom. In the third O site, O is bonded in a single-bond geometry to one Fe atom. In the fourth O site, O is bonded in a single-bond geometry to one Cr atom. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Cr and one Fe atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Cr and one Fe atom. In the seventh O site, O is bonded in a single-bond geometry to one Cr atom. In the Cr2FeO8 sheet, there are two inequivalent Cr sites. In the first Cr site, Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with three equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 24–59°. There are a spread of Cr–O bond distances ranging from 1.61–1.77 Å. In the second Cr site, Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with three equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 11–33°. There are a spread of Cr–O bond distances ranging from 1.60–1.71 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six CrO4 tetrahedra and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.10 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Cr and two equivalent Fe atoms. In the second O site, O is bonded in a linear geometry to one Cr and one Fe atom. In the third O site, O is bonded in a single-bond geometry to one Cr atom. In the fourth O site, O is bonded in a single-bond geometry to one Cr atom. In the fifth O site, O is bonded in a single-bond geometry to one Cr atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Cr and one Fe atom. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Cr and one Fe atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to one Cr and one Fe atom.
36 MATERIALS SCIENCE↗
Understanding how single-atom site density drives the performance and durability of PGM-free Fe–N–C cathodes in anion exchange membrane fuel cells
One of the most important needs for the future of low-cost fuel cells is the development of highly active platinum group metal (PGM)-free catalysts. For the oxygen reduction reaction, Fe–N–C materials have been widely studied in both acid and alkaline media. However, reported catalysts in the literature show quite different intrinsic activity and in-cell performance, despite similar synthesis routes and precursors. Here, two types of Fe–N–C are prepared from the same precursor and procedure – the main difference is how the precursor was handled prior to use. It is shown that in one case Fe overwhelmingly existed as highly active single-metal atoms in FeN4 coordination (preferred), while in the other case large Fe particles coexisting with few single metal atoms were obtained. As a result, there were drastic differences in the catalyst structure, activity, and especially in their performance in an operating anion exchange membrane fuel cell (AEMFC). Additionally, it is shown that catalyst layers created from single-atom-dominated Fe–N–C can have excellent performance and durability in an AEMFC using H 2 /O 2 reacting gases, achieving a peak power density of 1.8 W cm -2 – comparable to similar AEMFCs with a Pt/C cathode – and being able to operate stably for more than 100 h. Finally, the Fe–N–C cathode was paired with a low-loading PtRu/C anode electrode to create AEMFCs (on H 2 /O 2 ) with a total PGM loading of only 0.135 mg cm -2 (0.090 mg Pt cm -2 ) that was able to achieve a very high specific power of 8.4 W mg PGM -1 (12.6 W mg Pt< sup>-1 ).
36 MATERIALS SCIENCE↗
Materials Data on FeH2Cl5O3 by Materials Project
FeH2O3Cl5 is High Pressure (4-7GPa) Tellurium structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four FeH2O3Cl5 clusters. Fe is bonded in a 6-coordinate geometry to one O and five Cl atoms. The Fe–O bond length is 1.92 Å. There are a spread of Fe–Cl bond distances ranging from 2.29–2.58 Å. H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Fe atom. In the second O site, O is bonded in a single-bond geometry to one H and one Cl atom. The O–Cl bond length is 2.30 Å. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Fe atom. In the second Cl site, Cl is bonded in a distorted trigonal non-coplanar geometry to one Fe and two equivalent O atoms. In the third Cl site, Cl is bonded in a single-bond geometry to one Fe atom. In the fourth Cl site, Cl is bonded in a single-bond geometry to one Fe atom.
36 MATERIALS SCIENCE↗
Single‐Atomic Site Catalyst with Heme Enzymes‐Like Active Sites for Electrochemical Sensing of Hydrogen Peroxide
Abstract Heme enzymes, with the pentacoordinate heme iron active sites, possess high catalytic activity and selectivity in biosensing applications. However, they are still subject to limited catalytic stability in the complex environment and high cost for broad applications in electrochemical sensing. It is meaningful to develop a novel substitute that has a similar structure to some heme enzymes and mimics their enzyme activities. One emerging strategy is to design the Fe‐N‐C based single‐atomic site catalysts (SASCs). The obtained atomically dispersed Fe‐N x active sites can mimic the active sites of heme enzymes effectively. In this work, a SASC (Fe‐SASC/NW) is synthesized by doping single iron atoms in polypyrrole (PPy) derived carbon nanowire via a zinc‐atom‐assisted method. The proposed Fe‐SASC/NW shows high heme enzyme‐like catalytic performance for hydrogen peroxide (H 2 O 2 ) with a specific activity of 42.8 U mg −1 . An electrochemical sensor based on Fe‐SASC/NW is developed for the detection of H 2 O 2 . This sensor exhibits a wide detection concentration range from 5.0 × 10 −10 m to 0.5 m and an excellent limit of detection (LOD) of 46.35 × 10 −9 m . Such excellent catalytic activity and electrochemical sensing sensitivity are attributed to the isolated Fe‐N x active sites and their structural similarity with natural metalloproteases.
Ding, Shichao↗
Wood Carbon Based Single-Atom Catalyst for Rechargeable Zn–Air Batteries
Low-cost and efficient oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional electrocatalysts are vital for the applications of rechargeable Zn-air batteries (ZABs). Given the high catalytic activity of single-atom catalysts (SACs), preparing SACs on a large scale for ZABs is desirable but remains challenging. Herein, in situ formation of single-atom Fe-N-C catalysts on plate wood-based porous carbon is achieved via a facile Lewis acid pretreatment and carbonization process. Lewis acid FeCl3 pretreatment on the cell wall of wood not only produces abundant microchannels but also successfully introduces atomically dispersed Fe-N active species into the hierarchical structure. Such uniformly dispersive SACs on the hierarchical structure enhance the ORR/OER performance and durability. A ZAB using the catalyst in the cathode shows a high power density (70.2 mW cm -2 , at quasi solid state) and long-term stability. This work provides a new path for the large-scale preparation of high-performance SACs.
25 ENERGY STORAGE↗
Developing Platinum-Group-Metal-Free Catalysts for Oxygen Reduction Reaction in Acid: Beyond the Single Metal Site
This project is to develop M (x) -N-C catalysts with dense multiple metal center (MMC) sites to meet the DOE 2025 activity target of 0.044 mA/cm 2 at 0.9 V IR-free ., as well as other goals such as durability. We have made important contributions to both catalyst development and fundamental understandings of the active sites in M-N-C catalysts in this project. We successfully made M (x) -N-C catalysts with some multiple metal center (MMC) sites by combining ionothermal carbonization with chemical vapor deposition (CVD). These catalysts, however, are not as active as the most active single-atom Fe-N-C catalysts made by the similar CVD process, owing likely to the low site density and the presence of inorganic Fe species such as iron carbides and nanoparticles. The most significant accomplishments we achieved in this project are: (1) we unraveled the formation pathway of Fe-N 4 sites during pyrolysis step-by-step and identified the trans-metalation mechanism, in collaboration with Deborah Myers and her colleagues at Argonne National Laboratory (ANL); (2) inspired by this finding, we pioneered the CVD synthesis of M-N-C catalysts (M = Mn, Fe, and Co), in which the Fe-N-C catalyst by CVD demonstrated an ORR activity of 33 mA/cm 2 at 0.9 V in H 2 -O 2 proton exchange membrane fuel cells (PEMFCs), very close to the ultimate goal of 35 mA/cm 2 of our project. This catalyst is the first Fe-N-C catalyst that contains only D1 sites without the D2 sites; whereas D1 and D2 sites have been always identified by Mossbauer in previous Fe-N-C catalysts. This finding helps to understand what the D1 and D2 sites are and their roles in catalyzing the ORR. (3) by improving the mass transport of the carbon matrix prior to the CVD process, the revised Fe-N-C catalyst made by CVD delivered a maximum power density of 0.53 W/cm 2 in H 2 -air PEMFCs. The improvement strategy was partly inspired by the computational modeling work by Adam Weber from LBNL, the Co-PI of this project, by developing, coding, and exercising a continuum level model of transport phenomena within a PGM-free catalyst layer. The model demonstrated that local resistances combined with limited site density of the PGM-free catalyst can result in limiting currents and poor polarization performance. The model also gave design guidance for impact of ECSA and overall catalyst-layer thickness. However, both Fe-N-C and Co-N-C catalysts developed by CVD showed poor durability in PEMFCS, in comparison with the traditional M-N-C catalysts synthesized via regular pyrolysis process. Consequently, we did not achieve the proposed durability targets. Despite so, we believe the FeNC-CVD catalysts with the poor durability and D1 sites only provides an excellent platform to understand the degradation mechanism of Fe-N-C in PEMFCs, the most important challenge in the development of M-N-C catalysts.
08 HYDROGEN↗
Materials Data on FeSb(ClO)8 by Materials Project
FeCl2(O)4Sb(OCl3)2O2 crystallizes in the triclinic P1 space group. The structure is one-dimensional and consists of one hydrogen peroxide molecule; one FeCl2(O)4 cluster; and one Sb(OCl3)2 ribbon oriented in the (1, 0, 0) direction. In the FeCl2(O)4 cluster, Fe is bonded in a 6-coordinate geometry to four O and two Cl atoms. There are a spread of Fe–O bond distances ranging from 1.83–2.14 Å. There are one shorter (2.28 Å) and one longer (2.29 Å) Fe–Cl bond lengths. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Fe atom. In the second O site, O is bonded in a 2-coordinate geometry to one Fe and one O atom. The O–O bond length is 1.28 Å. In the third O site, O is bonded in a single-bond geometry to one Fe atom. In the fourth O site, O is bonded in a 2-coordinate geometry to one Fe and one O atom. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Fe atom. In the second Cl site, Cl is bonded in a single-bond geometry to one Fe atom. In the Sb(OCl3)2 ribbon, Sb is bonded in an octahedral geometry to six Cl atoms. There are a spread of Sb–Cl bond distances ranging from 2.36–2.51 Å. There are two inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one O and two Cl atoms. The O–O bond length is 2.01 Å. There are one shorter (2.41 Å) and one longer (2.50 Å) O–Cl bond lengths. In the second O site, O is bonded in a distorted L-shaped geometry to one O and one Cl atom. The O–Cl bond length is 2.45 Å. There are six inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Sb atom. In the second Cl site, Cl is bonded in a single-bond geometry to one Sb atom. In the third Cl site, Cl is bonded in a single-bond geometry to one Sb and one O atom. In the fourth Cl site, Cl is bonded in a single-bond geometry to one Sb and one O atom. In the fifth Cl site, Cl is bonded in a single-bond geometry to one Sb atom. In the sixth Cl site, Cl is bonded in a distorted single-bond geometry to one Sb and one O atom.
36 MATERIALS SCIENCE↗
Materials Data on Fe8N by Materials Project
Fe8N crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a distorted body-centered cubic geometry to eight equivalent Fe atoms. All Fe–Fe bond lengths are 2.55 Å. In the second Fe site, Fe is bonded in a single-bond geometry to one N atom. The Fe–N bond length is 1.83 Å. In the third Fe site, Fe is bonded in a single-bond geometry to four equivalent Fe and one N atom. The Fe–N bond length is 1.96 Å. N is bonded in an octahedral geometry to six Fe atoms.
36 MATERIALS SCIENCE↗
Environment of Metal–O–Fe Bonds Enabling High Activity in CO 2 Reduction on Single Metal Atoms and on Supported Nanoparticles
Single-atom catalysts are often reported to have catalytic properties that surpass those of nanoparticles, while a direct comparison of sites common and different for both is lacking. In this work, we show that single atoms of the Pt-group embedded into the surface of Fe 3 O 4 have a greatly enhanced interaction strength with CO 2 compared with Fe 3 O 4 surface. The strong CO 2 adsorption on single Rh atoms and corresponding low activation energies lead to two-orders-of-magnitude higher conversion rates of CO 2 compared to Rh nanoparticles. This high activity of single atoms stems from the partially oxidic state imposed by their coordination to the support. Fe 3 O 4 -supported Rh nanoparticles follow the behavior of single atoms for CO 2 interaction and reduction, which is attributed to the dominating role of partially oxidic sites at the Fe 3 O 4 -Rh interface. Thus, we show a likely common catalytic chemistry for two kinds of materials thought to be different, and we show that single atoms of Pt-group metals on Fe 3 O 4 are an especially successful material for catalyzed reactions that depend primarily upon sites with the metal-O-Fe environment.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Materials Data on Sm4Fe31(CoC2)3 by Materials Project
Sm4Fe31(CoC2)3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are a spread of Sm–Fe bond distances ranging from 3.10–3.36 Å. There are one shorter (2.51 Å) and two longer (2.52 Å) Sm–C bond lengths. In the second Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are a spread of Sm–Fe bond distances ranging from 3.11–3.36 Å. There are one shorter (2.51 Å) and two longer (2.52 Å) Sm–C bond lengths. In the third Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are a spread of Sm–Fe bond distances ranging from 3.14–3.37 Å. There are one shorter (2.50 Å) and two longer (2.51 Å) Sm–C bond lengths. In the fourth Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are a spread of Sm–Fe bond distances ranging from 3.12–3.36 Å. There are one shorter (2.50 Å) and two longer (2.51 Å) Sm–C bond lengths. There are thirty-one inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.38–2.75 Å. In the second Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.38–2.75 Å. In the third Fe site, Fe is bonded in a 3-coordinate geometry to one Sm, twelve Fe, and one Co atom. There are a spread of Fe–Fe bond distances ranging from 2.66–2.75 Å. The Fe–Co bond length is 2.65 Å. In the fourth Fe site, Fe is bonded in a 4-coordinate geometry to one Sm, eleven Fe, and two Co atoms. There are a spread of Fe–Fe bond distances ranging from 2.66–2.73 Å. There are one shorter (2.65 Å) and one longer (2.66 Å) Fe–Co bond lengths. In the fifth Fe site, Fe is bonded to two Sm, nine Fe, and one Co atom to form distorted FeSm2Fe9Co cuboctahedra that share corners with four FeSm2Fe8Co2 cuboctahedra, corners with two CSm2Fe4 octahedra, faces with four FeSm2Fe9Co cuboctahedra, and faces with four CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Fe–Fe bond distances ranging from 2.44–2.49 Å. The Fe–Co bond length is 2.47 Å. In the sixth Fe site, Fe is bonded to two Sm, nine Fe, and one Co atom to form distorted FeSm2Fe9Co cuboctahedra that share corners with four FeSm2Fe8Co2 cuboctahedra, corners with two CSm2Fe4 octahedra, faces with four FeSm2Fe8Co2 cuboctahedra, and faces with four CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Fe–Fe bond distances ranging from 2.44–2.49 Å. The Fe–Co bond length is 2.47 Å. In the seventh Fe site, Fe is bonded to two Sm, eight Fe, and two Co atoms to form distorted FeSm2Fe8Co2 cuboctahedra that share corners with four FeSm2Fe9Co cuboctahedra, corners with two CSm2Fe4 octahedra, faces with four FeSm2Fe9Co cuboctahedra, and faces with four CSm2Fe3Co octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Fe–Fe bond distances ranging from 2.44–2.49 Å. Both Fe–Co bond lengths are 2.47 Å. In the eighth Fe site, Fe is bonded to two Sm, nine Fe, and one Co atom to form distorted FeSm2Fe9Co cuboctahedra that share corners with four FeSm2Fe9Co cuboctahedra, corners with two CSm2Fe4 octahedra, faces with four FeSm2Fe9Co cuboctahedra, and faces with four CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.49 Å. The Fe–Co bond length is 2.47 Å. In the ninth Fe site, Fe is bonded to two Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with four FeSm2Fe9Co cuboctahedra, corners with two CSm2Fe3Co octahedra, faces with four FeSm2Fe9Co cuboctahedra, and faces with four CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 45–46°. There are four shorter (2.45 Å) and four longer (2.48 Å) Fe–Fe bond lengths. In the tenth Fe site, Fe is bonded to two Sm, nine Fe, and one Co atom to form distorted FeSm2Fe9Co cuboctahedra that share corners with four FeSm2Fe9Co cuboctahedra, corners with two CSm2Fe3Co octahedra, faces with four FeSm2Fe8Co2 cuboctahedra, and faces with four CSm2Fe3Co octahedra. The corner-sharing octahedra tilt angles range from 44–45°. There are a spread of Fe–Fe bond distances ranging from 2.44–2.48 Å. The Fe–Co bond length is 2.47 Å. In the eleventh Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the twelfth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the thirteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the fourteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the fifteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the sixteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the seventeenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the eighteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the nineteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the twentieth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the twenty-first Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.88 Å. In the twenty-second Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–C bond length is 1.89 Å. In the twenty-third Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. In the twenty-fourth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. In the twenty-fifth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. In the twenty-sixth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. In the twenty-seventh Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.90 Å. In the twenty-eighth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.92 Å. In the twenty-ninth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.90 Å. In the thirtieth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.92 Å. In the thirty-first Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.92 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded in a single-bond geometry to three Fe and one C atom. The Co–C bond length is 1.88 Å. In the second Co site, Co is bonded in a single-bond geometry to three Fe and one C atom. The Co–C bond length is 1.88 Å. In the third Co site, Co is bonded in a single-bond geometry to three Fe and one C atom. The Co–C bond length is 1.87 Å. There are six inequivalent C sites. In the first C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with two FeSm2Fe9Co cuboctahedra, corners with four CSm2Fe4 octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the second C site, C is bonded to two Sm, three Fe, and one Co atom to form CSm2Fe3Co octahedra that share corners with two FeSm2Fe9Co cuboctahedra, corners with four CSm2Fe4 octahedra, and faces with four FeSm2Fe8Co2 cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the third C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with two FeSm2Fe9Co cuboctahedra, corners with four CSm2Fe4 octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the fourth C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with two FeSm2Fe8Co2 cuboctahedra, corners with four CSm2Fe3Co octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the fifth C site, C is bonded to two Sm, three Fe, and one Co atom to form CSm2Fe3Co octahedra that share corners with two FeSm2Fe10 cuboctahedra, corners with four CSm2Fe4 octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the sixth C site, C is bonded to two Sm, three Fe, and one Co atom to form CSm2Fe3Co octahedra that share corners with two FeSm2Fe10 cuboctahedra, corners with four CSm2Fe4 octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°.
36 MATERIALS SCIENCE↗
Design and Preparation of Fe-N5 Catalytic Sites in Single-Atom Catalysts for Enhancing the Oxygen Reduction Reaction in Fuel Cells
Explore the source record for details and available documents.
99 GENERAL AND MISCELLANEOUS↗
Materials Data on Fe11MoC4 by Materials Project
MoFe5C2(Fe3C)2 crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one Fe3C sheet oriented in the (0, 1, 0) direction and one MoFe5C2 sheet oriented in the (0, 1, 0) direction. In the Fe3C sheet, there are four inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to one C atom. The Fe–C bond length is 1.79 Å. In the second Fe site, Fe is bonded in a single-bond geometry to one C atom. The Fe–C bond length is 1.88 Å. In the third Fe site, Fe is bonded in a square co-planar geometry to four C atoms. There are two shorter (2.01 Å) and two longer (2.04 Å) Fe–C bond lengths. In the fourth Fe site, Fe is bonded in a square co-planar geometry to four C atoms. There are a spread of Fe–C bond distances ranging from 1.99–2.04 Å. There are two inequivalent C sites. In the first C site, C is bonded to six Fe atoms to form a mixture of corner and edge-sharing CFe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second C site, C is bonded to six Fe atoms to form a mixture of corner and edge-sharing CFe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the MoFe5C2 sheet, Mo is bonded in a square co-planar geometry to four C atoms. There are a spread of Mo–C bond distances ranging from 2.10–2.12 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to one C atom. The Fe–C bond length is 1.89 Å. In the second Fe site, Fe is bonded in a single-bond geometry to one C atom. The Fe–C bond length is 1.90 Å. In the third Fe site, Fe is bonded in a square co-planar geometry to four C atoms. There are a spread of Fe–C bond distances ranging from 1.92–1.95 Å. There are two inequivalent C sites. In the first C site, C is bonded to two equivalent Mo and four Fe atoms to form a mixture of corner and edge-sharing CFe4Mo2 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second C site, C is bonded to two equivalent Mo and four Fe atoms to form a mixture of corner and edge-sharing CFe4Mo2 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.
36 MATERIALS SCIENCE↗
Materials Data on Sm2Fe15Co2C3 by Materials Project
Sm2Fe15Co2C3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are a spread of Sm–Fe bond distances ranging from 3.12–3.37 Å. There are two shorter (2.52 Å) and one longer (2.53 Å) Sm–C bond lengths. In the second Sm site, Sm is bonded in a distorted trigonal planar geometry to four Fe and three C atoms. There are one shorter (3.13 Å) and three longer (3.36 Å) Sm–Fe bond lengths. There are two shorter (2.51 Å) and one longer (2.52 Å) Sm–C bond lengths. There are ten inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.74 Å. The Fe–C bond length is 1.89 Å. In the second Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.74 Å. The Fe–C bond length is 1.88 Å. In the third Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.75 Å. The Fe–C bond length is 1.89 Å. In the fourth Fe site, Fe is bonded to two Sm, nine Fe, and one Co atom to form distorted FeSm2Fe9Co cuboctahedra that share corners with four FeSm2Fe9Co cuboctahedra, corners with two equivalent CSm2Fe3Co octahedra, faces with four FeSm2Fe9Co cuboctahedra, and faces with four CSm2Fe3Co octahedra. The corner-sharing octahedra tilt angles range from 45–46°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.67 Å. The Fe–Co bond length is 2.47 Å. In the fifth Fe site, Fe is bonded to two Sm, eight Fe, and two equivalent Co atoms to form distorted FeSm2Fe8Co2 cuboctahedra that share corners with four equivalent FeSm2Fe9Co cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, faces with four equivalent FeSm2Fe9Co cuboctahedra, and faces with four equivalent CSm2Fe3Co octahedra. The corner-sharing octahedral tilt angles are 45°. There are two shorter (2.49 Å) and two longer (2.67 Å) Fe–Fe bond lengths. Both Fe–Co bond lengths are 2.47 Å. In the sixth Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.37–2.66 Å. In the seventh Fe site, Fe is bonded in a 4-coordinate geometry to one Sm, eleven Fe, and two equivalent Co atoms. The Fe–Fe bond length is 2.66 Å. Both Fe–Co bond lengths are 2.65 Å. In the eighth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. In the ninth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.90 Å. In the tenth Fe site, Fe is bonded in a single-bond geometry to three Fe and one C atom. The Fe–C bond length is 1.91 Å. Co is bonded in a single-bond geometry to three Fe and one C atom. The Co–C bond length is 1.88 Å. There are two inequivalent C sites. In the first C site, C is bonded to two Sm, three Fe, and one Co atom to form CSm2Fe3Co octahedra that share corners with two equivalent FeSm2Fe9Co cuboctahedra, corners with four CSm2Fe3Co octahedra, and faces with four FeSm2Fe9Co cuboctahedra. The corner-sharing octahedra tilt angles range from 60–61°. In the second C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with two equivalent FeSm2Fe8Co2 cuboctahedra, corners with four equivalent CSm2Fe3Co octahedra, and faces with four equivalent FeSm2Fe9Co cuboctahedra. The corner-sharing octahedral tilt angles are 60°.
36 MATERIALS SCIENCE↗