Ultrasonic-assisted cathodic electrochemical discharge for graphene synthesis

Abstract

We present a novel and highly efficient method for exfoliating of graphite to produce graphene via the synergistic effects of in-situ plasma induced electrochemical exfoliation with ultrasonic energy, called ultrasonic-assisted cathodic electrochemical discharge. This method can work at moderate temperatures without the need of acidic media or expensive ionic electrolyte. The produced graphene exhibited a large lateral dimension of approximately 6μm and a thickness of 2.5nm, corresponding to approximately seven layers of graphene. An exfoliating mechanism of graphite to produce graphene sheets is also proposed in this study.

Ultrasonic-Assisted Cathodic Plasma Electrolysis Approach for Producing of Graphene Nanosheets

“…CPE is principally based on the reaction or vaporization of electrolyte and the electrical breaking of gaseous envelope, resulting in the formation of sparks around the active electrode [27][28][29]. The comprehensive reviews of plasma electrolysis can be found in some excellent reviews [15,25,26].…”

“…During ultrasonication with pressure oscillations, the cavitation and shear forces, as well as the collapse of the bubbles or voids on liquid, could activate both graphite intercalation and expansion, which leads to a complete exfoliation. A new ultrasonic-assisted cathodic electrochemical discharge approach has been developed to exfoliate graphene nanosheets from graphite rod by using a combination of ultrasonic energy and in situ plasmainduced electrochemical exfoliation [15]. Without expensive ionic liquid or acidic media, this method revealed broad benefits such as direct production of graphene at ambient pressure and low temperature as well as a facile, environmentally Ultrasonic-Assisted Cathodic Plasma Electrolysis Approach for Producing of Graphene Nanosheets DOI: http://dx.doi.org /10.5772/intechopen.89267 friendly, and fast process.…”

“…The extremely high-temperature outermost cathodic tip in the plasma zone leads to the expanding and cracking of graphite surrounding with weakening van der Waals forces. In this case, the violent fluctuation in the vapor plasma envelope and the cavitation from the sonication are Experimental setup for production of UPEEG: (1) cathode, (2) anode, (3) vapor plasma envelope, (4) ultrasonic cleaner; inset is image of cathodic electrochemical discharge phenomenon [15].…”

“…Due to the fact that bulk graphite involves several graphene sheets which are weakly bonded through van der Waals force, there is a great possibility for taking the advantage of a tremendous energy to break this force in graphitic structure. Although the electrochemical exfoliation [12,13] and ultrasound-assisted exfoliation [14,15] are extensively employed for preparation of graphene and its derivative, the review of ultrasound energy and cathodic electrochemical exfoliation process for high-yield graphene production has not been explored yet.…”

“…XPS C1s spectra of (A) HG and (B) UPEEG; (C) Raman spectra of HG and UPEEG; (D) proposed mechanism for the formation of graphene sheets[15].Ultrasonic-Assisted Cathodic Plasma Electrolysis Approach for Producing of Graphene Nanosheets DOI: http://dx.doi.org/10.5772/intechopen.89267Author detailsNguyen Van Truong 1 , Nguyen Quoc Dung 2 , Nguyen Nhat Huy 3 , Pham Van Hao 4 and Dang Van Thanh 5 * 1 Faculty of Fundamental Science, Thai Nguyen University of Technology, Vietnam 2 Department of Chemistry, Thai Nguyen University of Education, Vietnam 3 Faculty of Environment and Natural Resources, Ho Chi Minh City University of Technology, VNU-HCM, Vietnam 4 Faculty of Basic Science, TNU-University of Information and Communication Technology, Vietnam 5 Faculty of Basic Science, TNU-University of Medicine and Pharmacy, Vietnam *Address all correspondence to: thanhdv@tnmc.edu.vn…”