Graphene oxide-catalysed oxidation reaction of unsaturated compounds under microwave irradiation

2015 ◽  
Vol 72 ◽  
pp. 133-137 ◽  
Author(s):  
Jose M. Bermudez ◽  
J. Angel Menendez ◽  
Ana Arenillas ◽  
Rafael Martínez-Palou ◽  
Antonio A. Romero ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Oxidation Reaction ◽  
Unsaturated Compounds ◽  
Catalysed Oxidation

Rapid Nucleation of Reduced Graphene Oxide-Supported Palladium Electrocatalysts for Methanol Oxidation Reaction

2019 ◽  
Vol 19 (11) ◽  
pp. 7236-7243
Author(s):  
Jen Chao Ng ◽  
Chou Yong Tan ◽  
Boon Hoong Ong ◽  
Atsunori Matsuda ◽  
Wan Jefrey Basirun ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Reduced Graphene Oxide ◽  
Oxidation Reaction ◽  
Room Temperature ◽  
Methanol Oxidation Reaction ◽  
Ph Adjustment ◽  
Reduced Graphene ◽  
High Supersaturation ◽  
Supported Palladium

Small sized electrocatalysts, which can be obtained by rapid nucleation and high supersaturation are imperative for outstanding methanol oxidation reaction (MOR). Conventional microwave synthesis processes of electrocatalysts include ultrasonication, stirring, pH adjustment, and microwave irradiation of the precursor mixture. Ethylene glycol (EG), which serves as a reductant and solvent was added during the ultrasonication or stirring stage. However, this step and pH adjustment resulted in unintended multi-stage gradual nucleation. In this study, the microwave reduction approach was used to induce rapid nucleation and high supersaturation in order to fabricate small-sized reduced graphene oxide-supported palladium (Pd/rGO) electrocatalysts via the delayed addition of EG, elimination of the pH adjustment step, addition of sodium carbonate (Na2CO3), prior microwave irradiation of the EG mixed with Na2CO3, and addition of room temperature precursor mixture. Besides its role as a second reducing agent, the addition of Na2CO3 was primarily intended to generate an alkaline condition, which is essential for the high-performance of electrocatalysts. Moreover, the microwave irradiation of the EG and Na2CO3 mixture generated highly reactive free radicals that facilitate rapid nucleation. Meanwhile, the room temperature precursor mixture increased supersaturation. Results showed improved electrochemically active surface area (78.97 m2 g−1, 23.79% larger), MOR (434.49 mA mg−1, 37.96% higher) and stability.

Depositing reduced graphene oxide onto tungsten disulfide nanosheets via microwave irradiation: confirmation of four-electron transfer-assisted oxygen reduction and methanol oxidation reaction

2020 ◽  
Vol 44 (25) ◽  
pp. 10638-10647 ◽  
Author(s):  
Surya Veerendra Prabhakar Vattikuti ◽  
Patnamsetty Chidanandha Nagajyothi ◽  
Kamakshaiah Charyulu Devarayapalli ◽  
Jaesool Shim
Keyword(s):  
Electron Transfer ◽  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Oxygen Reduction ◽  
Reduced Graphene Oxide ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Methanol Oxidation Reaction ◽  
Core Shell ◽  
Reduced Graphene

Core–shell structured rGO@WS2 nanostructures exhibited four electron transfer towards the ORR and remarkable methanol oxidation reaction.

Synthesis and Study of Reduced Graphene Oxide layers under Microwave Irradiation

2018 ◽  
Vol 5 (2) ◽  
pp. 3403-3410 ◽  
Author(s):  
D. Sreedhar ◽  
Sandhya Devireddy ◽  
Vasudeva Rao Veeredhi
Keyword(s):  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Reduced Graphene Oxide ◽  
Oxide Layers ◽  
Reduced Graphene

scholarly journals Nucleation and growth controlled reduced graphene oxide–supported palladium electrocatalysts for methanol oxidation reaction

2019 ◽  
Vol 9 ◽  
pp. 184798041982717 ◽  
Author(s):  
Jen Chao Ng ◽  
Chou Yong Tan ◽  
Boon Hoong Ong ◽  
Atsunori Matsuda ◽  
Wan Jefrey Basirun ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Direct Methanol Fuel Cells ◽  
Precursor Solution ◽  
Nucleation And Growth ◽  
Methanol Oxidation Reaction ◽  
Reduced Graphene ◽  
Supported Palladium

In spite of advantages of direct methanol fuel cells, low methanol oxidation reaction and fuel crossover from anode to cathode, there remains a challenge that inhibits it from being commercialized. Active electrocatalysts are in high demand to promote the methanol oxidation reaction. The methanol reached at the anode can be immediately reacted, and thus, less methanol to cross to the cathode. The performance of electrocatalysts can be significantly influenced by varying the concentration of precursor solution. Theoretically, concentrated precursor solution facilitates rapid nucleation and growth; diluted precursor solution causes slow nucleation and growth. Rapid nucleation and slow growth have positive effect on the size of electrocatalysts which plays a significant role in the catalytic performance. Upon the addition of appropriate concentration of graphene oxide, the graphene oxide was reported to have stabilizing effect towards the catalyst nanoparticles. This work synthesized reduced graphene oxide–supported palladium electrocatalysts at different concentrations (0.5, 1.0, 2.0, 3.0 and 4.0 mg mL−1) with fixed volume and mass ratio of reduced graphene oxide to palladium by microwave-assisted reduction method. Results showed that reduced graphene oxide–supported palladium synthesized at a concentration of 1.0 mg mL−1 gave the best methanol oxidation reactivity (405.37 mA mg−1) and largest electrochemical active surface area (83.57 m2 g−1).

Arc spectra of different solid reduced graphene oxide samples under microwave irradiation

2020 ◽  
Vol 109 ◽  
pp. 108060
Author(s):  
Wenshuai Jiang ◽  
Zhenxin Li ◽  
Yongtao Zhu ◽  
Wei Xin ◽  
Yi Yu
Keyword(s):  
Graphene Oxide ◽  
Microwave Irradiation ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene
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