Synergistically enhanced oxygen reduction electrocatalysis by atomically dispersed and nanoscaled Co species in three-dimensional mesoporous Co, N-codoped carbon nanosheets network

Zhao, Shulin; Yang, Jing; Han, Min; Wang, Xiaoming; Lin, Yue; Yang, Rui; Xu, Dongdong; Shi, Nai; Wang, Qi; Yang, Minjun; Dai, Zhihui; Bao, Jianchun

doi:10.1016/j.apcatb.2019.118207

Cited by 82 publications

(33 citation statements)

References 70 publications

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“…As depicted in Figure B, the Tafel slope of Pd−Cr NSFSs (83 mV dec −1 ) is higher than that of Pd−Mo (80 mV dec −1 ) and Pd−W (60 mV dec −1 ) ones, proving the above ORR activity sequence for those Pd−M NSFSs. For quantitatively comparing their intrinsic activity, the kinetic current density ( j k ) or specific activity and mass activity ( j m ) of those Pd−M NSFSs catalysts are further calculated according to previously reported method . At the potential of 0.90 V ( vs .…”

Section: Resultsmentioning

confidence: 99%

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

et al. 2020

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Pd‐based nanoalloys are promising electrocatalysts for replacing Pt‐based ones toward oxygen reduction reaction. Despite that great progress has been achieved, universally synthesizing Pd‐based alloy nanosheets and further integrating them into porous or hierarchical superstructures remain a challenge, and their ORR performances are not systematically investigated. Herein, novel ultrathin and highly wrinkled Pd−M (M=Cr, Mo, W) alloy nanosheets flower‐like superstructures (NSFSs) are universally fabricated via a polyether and small molecules/ions ligand assisted solvothermal method. Such Pd−M NSFSs possess mesoporous structures and co‐exist single‐atom‐like and cluster‐like M species on their surfaces. Compared with pure Pd NSFSs, those Pd−M NSFSs show greatly enhanced ORR activity in alkaline media. Due to the unique microstructure feature, proper alloy constituent and stronger interatomic polarization or electronic coupling, the Pd−W NSFSs show the highest ORR activity with the half‐wave potential of 0.89 V (vs. RHE) and mass activity of 0.46 A mgPd−1 at 0.90 V (vs. RHE), outperforming commercial Pt/C, and most of reported Pd(or Pt)‐based catalysts. Moreover, the Pd−W NSFSs manifest outstanding durability and anti‐CO poisoning ability yet. This work may spur the development of 2D Pd‐based nanoalloy superstructures and promote their applications in fuel cells or other clean energy fields.

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Section: Resultsmentioning

confidence: 99%

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

et al. 2020

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“…For example, as shown in Figure 3(d), a KCl-assisted method was developed to prepare single-atom Co catalyst [54], in which a thin layer of ZIF-67 containing Co precursor grew on the surface of KCl particles, followed by annealing under argon at 750°C for 2 h and washing with diluted HCl and H 2 O to remove KCl template. With NaCl as the template, glucose as the carbon source, and FeCl 3 as the Fe precursor, Zhang et al prepared a single-atom Fe 1 -HNC-500-850 catalyst [68][69][70]. By mixing NaCl, glucose, and FeCl 3 in water followed by freeze drying, grinding, and pyrolyzing under NH 3 at 500°C and Ar at 850°C, single-atom FeN 4 sites were anchored on honeycomblike nanosheets (Fe 1 -HNC-500-850).…”

Section: 22mentioning

confidence: 99%

Recent Advances in Single-Atom Electrocatalysts for Oxygen Reduction Reaction

2020

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Oxygen reduction reaction (ORR) plays significant roles in electrochemical energy storage and conversion systems as well as clean synthesis of fine chemicals. However, the ORR process shows sluggish kinetics and requires platinum-group noble metal catalysts to accelerate the reaction. The high cost, rare reservation, and unsatisfied durability significantly impede large-scale commercialization of platinum-based catalysts. Single-atom electrocatalysts (SAECs) featuring with well-defined structure, high intrinsic activity, and maximum atom efficiency have emerged as a novel field in electrocatalytic science since it is promising to substitute expensive platinum-group noble metal catalysts. However, finely fabricating SAECs with uniform and highly dense active sites, fully maximizing the utilization efficiency of active sites, and maintaining the atomically isolated sites as single-atom centers under harsh electrocatalytic conditions remain urgent challenges. In this review, we summarized recent advances of SAECs in synthesis, characterization, oxygen reduction reaction (ORR) performance, and applications in ORR-related H2O2 production, metal-air batteries, and low-temperature fuel cells. Relevant progress on tailoring the coordination structure of isolated metal centers by doping other metals or ligands, enriching the concentration of single-atom sites by increasing metal loadings, and engineering the porosity and electronic structure of the support by optimizing the mass and electron transport are also reviewed. Moreover, general strategies to synthesize SAECs with high metal loadings on practical scale are highlighted, the deep learning algorithm for rational design of SAECs is introduced, and theoretical understanding of active-site structures of SAECs is discussed as well. Perspectives on future directions and remaining challenges of SAECs are presented.

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“…There are two possible pathways during ORR process, 4-electrons pathway and 2-electrons pathway. As presented in the following: 4)- (6). The reduction of O (ads) and OH (ads) is expressed as Equations ( 7) and ( 8), respectively.…”

Section: Possible Catalytic Pathways Of Orrmentioning

confidence: 99%

“…4,5 To develop the new, inexpensive and stable catalysts as alternatives to conventional Pt-based catalysts in fuel cells has attracted much attention. The catalytic activity and stability of transition metal-coordinated nitrogen-doped carbons (MN x -C) for ORR have been reported, [6][7][8][9][10] these compounds are promising candidates for Pt-based catalysts. 3,4 The introduced heteroatoms could tailor the electronic structure and charge distribution, and change local structure; thus creating new active sites.…”

Section: Introductionmentioning

confidence: 99%

Catalytic mechanism of oxygen reduction on two types of CoN ₄ ‐graphene : A density functional study

et al. 2021

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Co-coordinated nitrogen-doped carbons have been reported as highly active catalysts to oxygen reduction reaction (ORR) in fuel cell. Two CoN 4 -graphene catalysts with a hybrid structure of single Co atom embedded into pyridinic-N and pyrrolic-N doped graphenes, respectively, were studied. The detailed thermodynamic and kinetic behavior of the ORR on these two models was performed by DFT calculation. The results showed that both the two CoN 4 -G models possessed ORR activity. However, CoN 4 -G(A) catalyst showed higher catalytic activity but the CoN 4 -G(B) showed higher 4-electrons selectivity. On CoN 4 -G(A), both 2-electrons and 4-electrons pathways were feasible. Along the 4-electrons pathway, the OH reduction step was the thermodynamic and kinetic rate-determining step with the limiting potential of 0.43 V and a barrier of 0.42 eV. The formation barrier of H 2 O 2(ads) was 0.61 eV which was easy to overcome. Then the 2-electrons pathway was also possible. On CoN 4 -G(B), only 4-electrons ORR pathway was favorable. The most favorable reaction channel was arranged as: O 2 ! OOH ! 2OH ! OH + H 2 O ! 2H 2 O. The limiting potential of 4-electrons pathway was 0.35 V. The second step was the kinetic rate-determining step with the barrier of 0.86 eV.

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Synergistically enhanced oxygen reduction electrocatalysis by atomically dispersed and nanoscaled Co species in three-dimensional mesoporous Co, N-codoped carbon nanosheets network

Cited by 82 publications

References 70 publications

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

Recent Advances in Single-Atom Electrocatalysts for Oxygen Reduction Reaction

Catalytic mechanism of oxygen reduction on two types of CoN ₄ ‐graphene : A density functional study

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Synergistically enhanced oxygen reduction electrocatalysis by atomically dispersed and nanoscaled Co species in three-dimensional mesoporous Co, N-codoped carbon nanosheets network

Cited by 82 publications

References 70 publications

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

Recent Advances in Single-Atom Electrocatalysts for Oxygen Reduction Reaction

Catalytic mechanism of oxygen reduction on two types of CoN 4 ‐graphene : A density functional study

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Catalytic mechanism of oxygen reduction on two types of CoN ₄ ‐graphene : A density functional study