A comparative study on different aqueous-phase graphite exfoliation methods for few-layer graphene production and its application in alumina matrix composites

Río, Fidel del; Boado, Mónica G.; Rama, Adrián; Guitián, Francisco

doi:10.1016/j.jeurceramsoc.2017.04.029

Cited by 28 publications

(7 citation statements)

References 53 publications

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“…These values correspond to 500, 240, and 300% increase over the toughness of the monolithic ceramic, respectively. These values far exceed those of other carbon-reinforced ceramics ( 38 , 42 , 49 – 60 ). In terms of energy, the critical strain energy release rates for the brittle monolithic ceramics SiO 2 , Al 2 O 3 , and ZrO 2 are 8.9 ± 2, 86.6 ± 3, and 91.7 ± 4 J·m −2 , respectively.…”

Section: Resultsmentioning

confidence: 63%

Embedding two-dimensional graphene array in ceramic matrix

et al. 2020

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Dispersing two-dimensional (2D) graphene sheets in 3D material matrix becomes a promising route to access the exceptional mechanical and electrical properties of individual graphene sheets in bulk quantities for macroscopic applications. However, this is highly restricted by the uncontrolled distribution and orientation of the graphene sheets in 3D structures as well as the weak graphene-matrix bonding and poor load transfer. Here, we propose a previously unreported avenue to embed ordered 2D graphene array into ceramics matrix, where the catastrophic fracture failure mode of brittle ceramics was transformed into stable crack propagation behavior with 250 to 500% improvement in the mechanical toughness. An unprecedentedly low dry sliding friction coefficient of 0.06 in bulk ceramics was obtained mainly due to the inhibition of the microcrack propagation by the ordered 2D graphene array. These unique and low-cost 2D graphene array/ceramic composites may find applications in severe environments with superior structural and functional properties.

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Section: Resultsmentioning

confidence: 63%

Embedding two-dimensional graphene array in ceramic matrix

et al. 2020

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“…Because of the different parameters of the ultrasonic exfoliation process (e.g., time, frequency, power, and shape of the inner cavity), the experimental results are greatly affected (Río et al, 2017). At present, in the mechanical peeling process (including shearing and ball milling) (Deng et al, 2016;Liu Y. J. et al, 2018), the combination of shear and ball milling exfoliation process has been identified as the trend of replacing the ultrasonic peeling process in the future (Tour, 2014;Bonaccorso et al, 2016).…”

Section: Mechanical Exfoliationmentioning

confidence: 99%

Research Progress of the Liquid-Phase Exfoliation and Stable Dispersion Mechanism and Method of Graphene

Zhou

Jin

et al. 2019

Front. Mater.

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Graphene is a honeycomb hexagonal two-dimensional (2D) crystal nanomaterial with a thickness of only 0.334 nm. It has been widely used and studied because of its ultra-thin 2D nano-characteristics and excellent electrical, thermal, optical, and mechanical properties. With the continuous in-depth study of graphene, the liquid-phase dispersion of graphene has also achieved breakthroughs. This review summarizes the research progress of the liquid-phase exfoliation mechanism, exfoliation method, stable dispersion mechanism, and dispersion method of graphene in recent years. The research situations of the Hamaker constant theory in exfoliation mechanism and Hansen solubility coefficient theory in stable dispersion mechanism are mainly discussed. The shortcomings of the research are summarized and analyzes the graphene liquid phase dispersed in the important challenge in the future. The stable dispersion method of graphene is also summarized. In the future, the π-π interaction will be the most potential method for studying graphene stabilization.

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“…5,[23][24][25][26] Especially, the number of layers, thermal and electrical conductivity, hydrophobicity, solubility, defect and impurity fully depend on the used method. 14,[24][25][26][27][28] Additionally, the graphene supported electrocatalyst preparation methods such as chemical reduction, microwave synthesis and thermal treatment play essential role on the electrocatalytic activity due to restacking, deformation and aggregation. 7,17,20,21,29 Graphene nanoplatelets synthesized by exfoliating exhibits the advantages as a durable support with Pt electrocatalyst for oxygen reduction due to the high graphitization degree of graphene nanoplatelet.…”

Section: Introductionmentioning

confidence: 99%

PtCo on continuous‐phase graphene as PEM fuel cell catalyst

2020

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Summary For the first time, graphene grown by chemical vapor deposition (CVD) process is utilized as catalyst support following transfer onto polymer electrolyte membrane (M) or gas diffusion layer (GDL) as continuous‐phase. Thus, agglomeration and stacking of graphene sheets due to van der Waals forces are minimized. The main purpose of this study is investigation of PtCo atomic ratio on continuous‐phase graphene for PEM fuel cell. Eight different ratios of Pt (IV) and Co (II) salts are reduced on CVD grown graphene (G) sheet at room temperature using sodium borohydride to obtain varying PtCo nanoparticle compositions. Electrode activity increases with increasing atomic ratio of PtCo up to 1:3 both on membrane and gas diffusion layer for anode with the highest power densities of 1085 mW cm−2 (1:3‐PtCo/G‐M) and 1630 m W cm−2 (1:3‐PtCo/G‐GDL). For cathode, on the other hand, the highest performances are obtained with 1:2 PtCo/G‐M (355 mW cm−2 at 0.5 V) and 1:1 PtCo/G‐GDL (515 mW cm−2 at 0.5 V) compositions. The results show that the enhanced electrocatalytic activity is obtained at critical atomic ratio of Pt and Co due to changes in Pt‐Pt distances, d‐electron vacancy and adsorption. Continuous‐phase of graphene causes mass transfer limitations at the cathode effecting water removal at high current densities.

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A comparative study on different aqueous-phase graphite exfoliation methods for few-layer graphene production and its application in alumina matrix composites

Cited by 28 publications

References 53 publications

Embedding two-dimensional graphene array in ceramic matrix

Embedding two-dimensional graphene array in ceramic matrix

Research Progress of the Liquid-Phase Exfoliation and Stable Dispersion Mechanism and Method of Graphene

PtCo on continuous‐phase graphene as PEM fuel cell catalyst

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