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.

Sundara Ramaprabhu

Department Of Physics

Ashok Pullamsetty

Maheswari Subbiah

alcohols

Cyclic voltammetry

Electrocatalysts

Electrolytic reduction

Fuel cells

Graphene

Nanoparticles

Platinum

Synthesis (chemical)

X ray diffraction

BORON-DOPED GRAPHENE

Electrochemically active surface areas

Oxygen reduction reaction

Platinum nano-particles

Polarization study

POLYOL REDUCTIONS

Sodium boro hydrides

TRANSMISSION ELECTRONIC MICROSCOPIES

Proton exchange membrane fuel cells (PEMFC)

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

International Journal of Hydrogen Energy

Herein, 1-D carbon nanotubes and 2-D graphene hybrid carbon hetero-structure is employed as the catalyst support material for low temperature fuel cell. Partial unraveling of carbon nanotubes results in 1D-2D hybrid hetero-structure with enhanced surface area, while the intact inner tubes result in good electrical conductivity. Platinum-tin alloy decorated on partially exfoliated carbon nanotubes (Pt–Sn/PCNT) were prepared by ethylene glycol reduction method and investigated its electrocatalytic activity towards ethanol oxidation reaction (EOR) for direct ethanol fuel cell (DEFC) and oxygen reduction reaction (ORR) for hydrogen fuelled polymer electrolyte membrane fuel cell (PEMFC). Along with the intrinsic properties of carbon nanotubes, PCNT provides more anchoring sites, thereby facilitates complete utilization of catalysts. The electrochemical EOR studies reveal that Pt–Sn/PCNT has better tolerance to the accumulation of intermediate species than Pt–Sn/CNT. Besides, as-synthesized electrocatalysts exhibit good ORR activity with four-electron pathway. The enhanced EOR and ORR activity of as prepared electrocatalysts is attributed to the high dispersion of catalyst nanoparticles on PCNT along with the inhibition of production of intermediate species on the Pt surface by alloying. Further, the practical suitability of PCNT supported Pt–Sn nanocatalysts as EOR and ORR electrocatalysts has been examined by performing the full fuel cell measurements. © 2019 Hydrogen Energy Publications LLC

1D-2D integrated hybrid carbon nanostructure supported bimetallic alloy catalyst for ethanol oxidation and oxygen reduction reactions

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

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

Abstract: In this work, we report a facile and one -step hydrothermal method to decorate SnO2 nanostructures on few-layered graphene for superior dopamine detection. The structural and morphological properties of the prepared nanohybrids illustrated the tetragonal crystal system of SnO2, reconstruction of graphene layers with oxygen containing functional groups, increased ID/IG ratio, and uniform decoration of SnO2 nanostructures on graphene layers. The prepared nanohybrids exhibited a high electrochemical activity toward dopamine oxidation in comparison with individual graphene sheets. This enhanced performance can be due to the presence of SnO2 nanostructures between the graphene layers, which efficiently avoid the restacking and increase the surface area accessibility. The fabricated nanohybrid-based sensor showed an increase in current with respect to the increased analyte concentration over the wide range of 0.005–0.20 × 10−6 M. The sensor exhibits excellent catalytic activity toward dopamine with the lowest detection limit of 6.3 nm. Further, the modified electrode exhibited good stability, reproducibility, and better recovery of 99 % in human urine samples suggesting the real-time usability of the sensor. Graphical Abstract: Schematic representation of SnO2 nanohybrids formation. The modified electrode exhibits superior catalytic activity. The oxidation peak current increased linearly in the concentration range of 0.005–0.019 × 10−6 M with LOD of 6.3 nm.[Figure not available: see fulltext.] © 2016, Springer Science+Business Media Dordrecht.

Journal of Applied Electrochemistry

One-step in situ hydrothermal preparation of graphene–SnO2 nanohybrid for superior dopamine detection

Graphitic carbon nitride has attracted huge interest due to its due to low cost and easy synthesis. We report for the first time graphitic carbon nitride composite as room temperature hydrogen sensing material. Nano structured palladium nanoparticle dispersed graphitic carbon nitride (Pd/g-C3N4) composite was investigated as room temperature resistive gas sensor. Graphitic carbon nitride (g-C3N4) was prepared by pyrolysis of melamine. Palladium nanoparticles were dispersed on g-C3N4 by polyol reduction method. Hydrogen sensing properties of Pd/g-C3N4 were studied within near flammability range from 1 to 4 vol%. The performance was evaluated with variation in temperature from 30 to 80 °C. For 4% H2 at room temperature, 99.8% sensitivity is achieved with response time of 88 s while for the same concentration of H2 at 80 °C, the sensor shows 97.4% sensitivity. The results show prospect of reliable sensing material. © 2016 Hydrogen Energy Publications LLC

Nanostructured palladium modified graphitic carbon nitride – High performance room temperature hydrogen sensor

Reduced graphene oxide (rGO) and nitrogen doped graphene (NG) have been used as a support for decorating the platinum (Pt) and yttrium (Y) alloy (Pt3Y) nanoparticles. Pt3Y nanoparticles decorated graphene (Pt3Y/G) and Pt3Y nanoparticles decorated nitrogen doped graphene (Pt3Y/NG) have been applied as oxygen reduction reaction (ORR) electrocatalysts in proton exchange membrane fuel cells. The electrochemically active surface area has been measured by Cyclic Voltammetry (CV). The ORR activity has been investigated by polarization studies using fuel cell fixture. The enhanced catalytic activity of Pt3Y/NG towards ORR is due to homogeneous dispersion and optimum particle size of Pt3Y alloy nanoparticles over the surface of NG. This study revealed that, Pt3Y/NG is more ORR active than Pt3Y/G. Copyright © 2016 American Scientific Publishers.

Journal of Nanoscience and Nanotechnology

Investigation of electrocatalytic activity of pt-y alloy nanoparticles dispersed on nitrogen doped graphene for proton exchange membrane fuel cell

The present work demonstrates a facile route for the large-scale, catalyst free, and green synthesis approach of boron doped graphene (B-G) and its use as high performance anode material for Li ion battery (LIB) application. Boron atoms were doped into graphene framework with an atomic percentage of 5.93% via hydrogen induced thermal reduction technique using graphite oxide and boric acid as precursors. Various characterization techniques were used to confirm the boron doping in graphene sheets. B-G as anode material shows a discharge capacity of 548 mAh g-1 at 100 mA g-1 after 30th cycles. At high current density value of 1 A g-1, B-G as anode material enhances the specific capacity by about 1.7 times compared to pristine graphene. The present study shows a simplistic way of boron doping in graphene leading to an enhanced Li ion adsorption due to the change in electronic states. © 2014 Elsevier B.V. All rights reserved.

Materials Research Bulletin

Green synthesis of boron doped graphene and its application as high performance anode material in Li ion battery

Nitrogen doped graphene has been synthesized using hydrothermal method and thermal solid state method with ammonia and melamine as nitrogen sources respectively. Platinum nanoparticles have been dispersed over these support materials using polyol method and these Pt loaded nitrogen doped graphene samples have been studied as electrocatalyst for oxygen reduction reaction (ORR) in a proton exchange membrane fuel cell and for methanol oxidation reaction (MOR). Also, the role of multiwalled carbon nanotubes as a spacer which avoids face to face agglomeration of graphene sheets has also been studied for both the samples. The morphology and structure of the graphene based powder samples have been studied using X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Half cell and full cell measurements have been performed on the samples for ORR and MOR. With the use of functionalized multiwalled carbon nanotubes, a maximum power density of 704 mW cm-2 and 650 mW cm-2 has been obtained with Pt dispersed nitrogen doped graphenes prepared by hydrothermal and thermal solid state methods respectively. The results have been compared with commercial Pt/C catalyst. © 2015 Hydrogen Energy Publications, LLC.

Nitrogen doped graphene prepared by hydrothermal and thermal solid state methods as catalyst supports for fuel cell

In the present study, platinum nanoparticles decorated on graphene sheets have been employed as electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction in proton exchange membrane fuel cells. A green and simple approach has been followed for the reduction of graphite oxide using l-ascorbic acid (l-ARGO). Platinum nanoparticle decoration on graphene (Pt/l-ARGO) sheets has been carried out by polyol reduction technique. The structural and morphological characterizations have been performed by different characterization techniques to confirm the formation of materials. The power densities have been evaluated from the recorded polarization curves. The single cell measurements show that the electrocatalytic activity of Pt/l-ARGO is superior in comparison to chemically reduced Pt-graphene systems. This journal is © the Partner Organisations 2014.

Journal of Materials Chemistry A

Platinum-graphene hybrid nanostructure as anode and cathode electrocatalysts in proton exchange membrane fuel cells

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

The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)-multiwalled carbon nanotubes (MWNTs)) hybrid structure (N-(G-MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO-negatively surface charged MWNTs) followed by the pyrolysis of these (rGO-MWNTs) hybrid structure-polymer composites. The N-(G-MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum-iron (Pt 3Fe) and platinum-cobalt (Pt3Co) alloy nanoparticles. The PEMFC performances of Pt-TM alloy nanoparticle dispersed N-(G-MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt-C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications. © 2013 The Royal Society of Chemistry.

Nanoscale

Platinum-TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications

Journal	Data powered by TypesetInternational Journal of Hydrogen Energy
Publisher	Data powered by TypesetElsevier Ltd
ISSN	03603199
Open Access	No