Boron doped graphene was prepared by a facile method and platinum (Pt) decoration over boron doped graphene was done in various chemical reduction methods such as sodium borohydride (NaBH4), polyol and modified polyol. X-ray diffraction analysis indicates that the synthesized catalyst particles are present in a nanocrystalline structure and transmission and scanning electron microscopy were employed to investigate the morphology and particle distribution. The electrochemical properties were investigated with the help of the rotating disk electrode (RDE) technique and cyclic voltammetry. The results show that the oxygen reduction reaction (ORR) takes place by a four-electron process. The kinetics of the ORR was evaluated using K-L and Tafel plots. The electrocatalyst obtained in modified polyol reduction method has shown the better catalytic activity compared to other two electrocatalysts. © 2016 .

Sundara Ramaprabhu

Department Of Physics

Ashok Pullamsetty

alcohols

Catalyst activity

Cyclic voltammetry

Electrocatalysts

Electrolytic reduction

Graphene

Nanocrystals

Oxygen

Platinum

reduction

Rotating disks

Scanning electron microscopy

X ray diffraction analysis

BORON-DOPED GRAPHENE

Nanoparticle (NPs)

Oxygen reduction reaction

PROTON EXCHANGE MEMBRANE FUEL CELL (PEMFCS)

TAFEL SLOPES

Proton exchange membrane fuel cells (PEMFC)

boron

polyol

Sodium borohydride

article

catalysis

catalyst

chemical structure

current density

cyclic potentiometry

Kinetic parameters

priority journal

synthesis

thermogravimetry

Transmission electron microscopy

X ray diffraction

X ray photoelectron spectroscopy

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Colloid and Interface Science

The integration of polymer electrolyte membrane fuel cell (PEMFC) stack into vehicles necessitates the replacement of high-priced platinum (Pt)-based electrocatalyst, which contributes to about 45% of the cost of the stack. The implementation of high-performance and durable Pt metal-free catalyst for both oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) could significantly enable large-scale commercialization of fuel cell-powered vehicles. Towards this goal, a simple, scalable, single-step synthesis method was adopted to develop palladium-cobalt alloy supported on nitrogen-doped reduced graphene oxide (Pd3Co/NG) nanocomposite. Rotating ring-disk electrode (RRDE) studies for the electrochemical activity towards ORR indicates that ORR proceeds via nearly four-electron mechanism. Besides, the mass activity of Pd3Co/NG shows an enhancement of 1.6 times compared to that of Pd/NG. The full fuel cell measurements were carried out using Pd3Co/NG at the anode, cathode in conjunction with Pt/C and simultaneously at both anode and cathode. A maximum power density of 68 mW/cm2 is accomplished from the simultaneous use of Pd3Co/NG as both anode and cathode electrocatalyst with individual loading of 0.5 mg/cm2 at 60 °C without any backpressure. To the best of our knowledge, the present study is the first of its kind of a fully non-Pt based PEM full cell. © 2018 The Author(s).

Fulltext

Scientific Reports

High-performance Platinum-free oxygen reduction reaction and hydrogen oxidation reaction catalyst in polymer electrolyte membrane fuel cell

The present work describes the potential of a hybrid carbon hetero-structure having the unique properties of one-dimensional carbon nanotubes and two-dimensional graphene as a catalyst support material for platinum-free electrocatalysts in polymer electrolyte membrane fuel cell (PEMFC) for hydrogen oxidation reaction (HOR) or oxygen reduction reaction (ORR). Partially exfoliated carbon nanotubes (PCNT), which have the synergistic effect of good electrical conductivity and high surface area, have been used as the support material for Pd3Co alloy catalysts. This provides more active sites for the dispersion of catalyst particles along with quick electron transport through the carbon structure. This unique characteristic increases the catalytic activity of the electrocatalysts. The electrochemical half-cell studies confirm that, ORR on Pd3Co/PCNT proceeds via a four-electron process. The single cell measurements were carried out by preparing a membrane electrode assembly (MEA) using Pd3Co/PCNT at the anode, cathode separately as well as simultaneously at both the anode and cathode. A maximum power density of 327 mW cm−2, 240 mW cm−2 and 96 mW cm−2 is attained from the use of Pd3Co/PCNT nanocomposite at anode, cathode and at both electrodes simultaneously in a PEMFC at 60 °C, respectively. © 2018 Hydrogen Energy Publications LLC

International Journal of Hydrogen Energy

Catalytic performance of non-platinum-based hybrid carbon hetero-structure for oxygen reduction and hydrogen oxidation reactions in proton exchange membrane fuel cell

The uniqueness in the physical and electrochemical properties and the structural integrity towards lithium ion storage make carbon nanotubes (CNT) a viable anode material for the lithium ion battery. But the morphology dependent electrochemical performance and high irreversibility in capacity stand as stumbling blocks to its commercialization. Herein, we demonstrate that irreversible capacity and short cycle life in CNT based anode material can be eliminated by exfoliation of a few of its outer layers with the incorporation of sulfur. The incorporation of sulfur brings in two lithium ion storage mechanisms in the electrode, insertion and sulfur redox reaction. We have observed this phenomenon by cyclic voltammetry and the corresponding behavioral change by dynamic electrochemical impedance spectroscopy. The assembled battery has been tested for various current densities from 150 to 40 000 mA g−1. The cell retained a capacity of 200 mA h g−1 for 7370 cycles at 10 000 mA g−1, proving the capability of the material for long cycle life even at higher current densities. The ultrahigh capacity of 1120 mA h g−1 at 150 mA g−1 after 10 000 cycles reveals its great potential as an anode material for commercial lithium ion batteries. © The Royal Society of Chemistry.

Journal of Materials Chemistry A

Binary reaction ingrained high current density and long cycle life novel anode material for lithium ion battery

Graphene Oxide-Molecular Imprinted Polymer (GO-MIP) based electrochemical sensor was developed for the first time towards enzyme less determination of glucose. This GO-MIP was obtained from a series of fictionalization, polymerization and template molecule introduction/removal during the synthesizing process. The proposed GO-MIP based electrode showed excellent electrocatalytic activity towards glucose oxidation at optimized conditions and possessing detection limit of 0.1 nM with a response time of ~ 2 min. The current response of GO-MIP based glucose sensor was linearly related to the concentration of glucose. The results obtained from the real time usability of electrodes in human blood matches well with commercially available glucose monitors. Further, the reusability of the material is checked up to eight cycles and interference of glucose with ascorbic acid (AA), uric acid (UA) and dopamine (DA) were also studied. The obtained results endorse the promising application of GO-MIP towards superior glucose sensing with long term stability. © 2017 Elsevier B.V.

Materials Science and Engineering C

Highly sensitive and selective non enzymatic electrochemical glucose sensors based on Graphene Oxide-Molecular Imprinted Polymer

Graphene is a promising electrode material for supercapacitor applications due to its unique properties. Interaction of electrolyte ions with graphene lattice sites is a crucial factor in ionic liquid electrolyte based supercapacitors. In an effort to increase the interaction of high viscous electrolyte with electrode material, here, we here report the results of a systematic study carried out on a supercapacitor with nitrogen doped graphene as electrode material and [BMIM][TFSI] as electrolyte. In this study, nitrogen doped hydrogen exfoliated graphene (N-HEG) is prepared by radio frequency (R.F) magnetron sputtering and employed as electrode material for [BMIM][TFSI] electrolyte based high performance supercapacitor. N-HEG shows a high specific capacitance of 170.1 F/g compared to that of electrolyte modified graphene (124.5 F/g), at a specific current of 2 A/g. The improved performance of N-HEG based supercapacitor is attributed to the presence of nitrogen atoms in the graphene lattice which in turn increases the lattice-ion interaction and the electrical conductivity. In addition, the presence of wrinkles on the graphene surface provides a shortest directional path to access pores and surface. The device shows high charge storage capacity (72.37 Wh/kg) along with wide operating voltage (3.5 V) and high cyclic stability. Copyright © 2015 American Scientific Publishers All rights reserved.

Journal of Nanoscience and Nanotechnology

Nitrogen-doped graphene for ionic liquid based supercapacitors

Boron doped graphene (BG) has been prepared using a facile technique and platinum (Pt) nanoparticles has been deposited on BG using different methods like sodium borohydride, polyol and modified polyol reduction method and used as oxygen reduction reaction (ORR) electrocatalyst in hydrogen fuel cell. The identification of crystal phases through X-ray diffraction (XRD) and the dispersion of the electrocatalyst by the Transmission Electronic Microscopy (TEM) have been studied. The electrochemically active surface area has been investigated by Cyclic Voltammetry (CV). The ORR activity has been evaluated by polarization studies using fuel cell fixture. Stability test also conducted in fuel cell mode for 50 h. This study revealed the superior ORR activity and stability of platinum nanoparticles decorated BG, which is synthesized by modified polyol reduction technique. Hence it can be considered as the alternative electrocatalyst for replacing contemporary electrocatalysts. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Platinum on boron doped graphene as cathode electrocatalyst for proton exchange membrane fuel cells

Non-precious metal electrocatalysts based on pyrolysed metal-nitrogen-carbon (MNC) are viewed as an inexpensive replacement for platinum-based electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells. One of the drawbacks of all the reported procedures to synthesize MNC electrocatalysts is the inability to control the nitrogen content. Since the type of nitrogen present (pyridinic, pyrrolic, quaternary/graphitic) and their proportions both play a seminal role in deciding the ORR activity of the electrocatalyst, it is important to carefully study the effect of nitrogen content on electrocatalyst properties. In this study, selenium was used as a ligand to replace the nitrogen coordinated to the iron atom in the electrocatalyst, thereby imparting control on the nitrogen content. Upon introducing 14 at% of selenium, the Ncontent of the catalyst dropped to 3.7 wt% and the ORR activity reached a maximum of 7.2 mA cm-2 at 0.8 V vs. RHE. We demonstrated the need for iron to complete the active site: upon complexing the iron site with bipyridine, ethylene diammine and oxalic acid in 1N H2SO4, the overpotential toward the ORR increased by ∼60 mV, ∼140 mV and ∼140 mV respectively at 2 mA cm-2. © 2015 The Electrochemical Society.

Journal of the Electrochemical Society

Controlling the nitrogen content of metal-nitrogen-carbon based non-precious-metal electrocatalysts via selenium addition

The fabrication of a novel amperometric biosensor based on selective determination of dopamine (DA) using nafion coated cerium oxide nanoparticles (NPs) decorated graphene nanosheets (CeO2-HEG-nafion) as a transducer candidate is reported. Graphene was synthesized by hydrogen exfoliation technique. Decoration of CeO2 NPs over graphene nanosheets was done by chemical reduction method. The electrochemical impedance spectroscopy (EIS) study shows the enhanced electron transfer kinetics of the composite compared to HEG modified and bare glassy carbon electrode (GCE). The response of the composite towards dopamine displays a lower oxidation potential of 0.23 V and a high oxidation current. The sensor exhibits linearity from 10 μM to 780 μM with a detection limit of 1 μM. In the presence of nafion, it shows excellent selectivity for coexisting interference species like Ascorbic acid (AA) and Uric acid (UA). The excellent performance of the biosensor can be attributed to large active surface area, enhanced electron transfer kinetics and high catalytic activity of the composite. Copyright © 2015 American Scientific Publishers All rights reserved.

Cerium oxide nanoparticles decorated graphene nanosheets for selective detection of dopamine

Development of lightweight materials with high hydrogen storage capacities is a great challenge for the hydrogen economy. Here, we report high pressure hydrogen adsorption-desorption studies of platinum-decorated hydrogen-exfoliated graphene sheets (Pt-HEG). Pt-HEG shows a maximum hydrogen uptake capacity of 1.4 wt% at 25 °C and 3 MPa. Analysis of the isosteric heat of adsorption provides evidence of spillover mechanism. © the Owner Societies.

Physical Chemistry Chemical Physics

Hydrogen storage in platinum decorated hydrogen exfoliated graphene sheets by spillover mechanism

Investigation of catalytic activity towards oxygen reduction reaction of Pt dispersed on boron doped graphene in acid medium

Journal	Journal of Colloid and Interface Science
Publisher	Academic Press Inc.
ISSN	00219797
Open Access	No