@article {45972, title = {Facile gamma radiolytic synthesis of synergistic Co3O4-rGO nanocomposite: direct use in photocatalytic water splitting}, journal = { Materials Research Express}, volume = {1}, year = {2014}, month = {DEC}, pages = {045507}, type = {Artical}, abstract = {

Nanostructured Co3O4 was synthesized through a gamma (gamma)-radiolysis technique using alcoholic (iso-propanol) salt solutions of cobalt ions with and without suspended graphene oxide (GO) nanoparticles, respectively. Formation of Co3O4 accompanied with GO reduction takes place simultaneously (in situ) upon.-ray exposure carried out at a rate of 5.1 KGy h(-1). Reduction of GO and formation of Co3O4 were confirmed by XRD, Raman and UV-vis spectroscopy. XRD and HRTEM results supports the embedding of nano-crystalline Co3O4 in an amorphous matrix. Relatively larger crystallites of cobalt oxide obtained in the presence of rGO proved to be a decisive supporting material for the directional growth of Co3O4. Electrochemical characterization established the fact that rGO is indeed considered as a proficient medium for electrochemical electron transfer process. Photo-assisted H-2 generation studies using Co3O4 and Co3O4-rGO nano-composite yielded 3 and 30 mu mol h(-1) g(-1) of hydrogen (H-2) generation, respectively, supports the action of rGO as an electron trap.

}, keywords = {nano cobalt oxide, photocatalytic hydrogen production, Reduced graphene oxide}, issn = {2053-1591}, doi = {10.1088/2053-1591/1/4/045507}, author = {Gupta, Bhavana and Melvin, Ambrose A. and Matthews, Tom and Dash, S. and Tyagi, A. K.} } @article { ISI:000353753200006, title = {Facile gamma radiolytic methodology for TiO2-rGO synthesis: effect on photo-catalytic H-2 evolution}, journal = {International Journal of Hydrogen Energy}, volume = {40}, number = {17}, year = {2015}, month = {MAY}, pages = {5815-5823}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

TiO2 (P25) decorated reduced graphene oxide (rGO) is synthesized by gamma-radiolytic technique using water-ethanol solvent medium. Visible light absorpdon was confirmed by UV-Visible spectroscopy. Photoluminescence (PL) study revealed a decline in electron-hole recombination rate signalled by a sharp fall in luminescence of TiO2. Under such scenario, electron transfer from TiO2 conduction band to the conjugated sheet becomes a preferred pathway in the presence of rGO, which is further confirmed by photocurrent measurement. TiO2 -rGO composite with 1 wt. \% rGO was found to be the best composition in terms of visible light absorption, while retaining TiO2 crystallinity. Transmission electron microscopy and Raman spectroscopic studies confirmed the coating of rGO sheet with TiO2 nanoparticles. TiO2 -rGO was found to show about 150 times higher photocatalytic H-2 generation under 250 W UV-Visible light irradiation than pristine TiO2. In addition to this, TiO2 -rGO composite shows hydrogen production yield of 35 mu mol/h.g under visible light (lambda = 400 nm) irradiation. Thus gamma-radiolysis can be considered to be a viable technique, which helps in synthesizing photocatalytically active nanocomposite with high H-2 evolution rate. In the light of these interesting aspects, a detail investigation is carried out to study the effect of rGO concentration and illumination time on photocatalytic yield. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

}, keywords = {gamma-radiolysis, H-2 production, Photocatalysis, Reduced graphene oxide, TiO2}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2015.02.102}, author = {Gupta, Bhavana and Melvin, Ambrose A. and Matthews, Tom and Dhara, S. and Dash, Sitaram and Tyagi, A. K.} } @article {43888, title = {TiO2/RGO composites: Its achievement and factors involved in hydrogen production}, journal = {Renewable \&sustainable energy reviews}, volume = {76}, year = {2017}, month = {SEP}, pages = {1384-1392}, type = {Article}, abstract = {

The immense potential shown by TiO2 to participate as a designer material resulting into a new class of high performing photocatalyst has acclaimed it to become an important player in the designing and synthesis of various solar harvesting materials. This role has further been explored by the introduction of graphene into TiO2 matrix. TiO2/reduced graphene oxide (TiO2/RGO) or TiO2/graphene (TiO2/GR) has shown its prospects or relevance to be considered as the next generation photocatalyst for hydrogen production by its reported values in terms of producing hydrogen gas. Hence, there is a requirement of having a detailed up to date write up on the work done in this area in terms of its synthetic procedures, properties and its effect on hydrogen production. Herein, we discuss the different methods involved in the synthesis of such highly efficient materials followed by a brief explanation on its structural and morphological properties. Furthermore, a comparative study on the recent developments in terms of hydrogen evolution efficiency along with a mechanistic approach is also described. Finally, the current challenge and possibility of the future development in this direction is emphasized.

}, keywords = {Au-tio2 Photocatalysts, Evolution, Generation, graphene, Hydrogen generation, Nanocomposite, Nitrogen-doped Tio2, Photocatalysis, Photocatalytic H-2 Production, Recent Progress, Reduced graphene oxide, TiO2, Tio2-graphene Nanocomposites, Visible-light Irradiation, Water}, issn = {1364-0321}, doi = {10.1016/j.rser.2017.03.1}, author = {Gupta, Bhavana and Melvin, Ambrose A.} } @article {46057, title = {Realization of efficient field emitter based on reduced graphene oxide-Bi2S3 heterostructures}, journal = {Physica Status Solidi A-Applications and Materials Science}, year = {2019}, month = {JUL}, pages = {1900121}, type = {Article; Early Access}, abstract = {

Herein, Bi2S3 nanorods and reduced graphene oxide (rGO)-Bi2S3 heterostructures are synthesized using a simple hydrothermal method. The structural, morphological, chemical, and elemental analysis of as-synthesized materials is performed using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Field emission (FE) studies are carried out on both pristine Bi2S3 nanorods and rGO-Bi2S3 heterostructure samples at a base pressure of approximate to 1 x 10(-8) mbar. The results show that the rGO-Bi2S3 heterostructure emitter has superior FE performance compared to pristine Bi2S3 emitters in terms of the turn-on field (2.6 V mu m(-1) at 10 mu A cm(-2)) and threshold field (4.0 V mu m(-1) at 100 mu A cm(-2)) along with a high emission current density of approximate to 1464 mu A cm(-2) at an applied electric field of 7.0 V mu m(-1). The rGO-Bi2S3 heterostructure emitter exhibits very good emission current stability, tested for more than 3 h duration, characterized by standard deviation values approximate to 2.84 and 4.06, corresponding to preset values 12 and 100 mu A. This study implies that one-step hydrothermal route can be efficiently used to synthesize organic-inorganic heterostructures that possess unique morphology. Furthermore, the synthesized rGO-Bi2S3 heterostructure emitter shows potential as an electron source for practical application in vacuum microelectronic devices.

}, keywords = {Bi2S3, field emission, Heterostructures, Nanorods, Reduced graphene oxide}, issn = {1862-6300}, doi = {10.1002/pssa.201900121}, author = {Gote, Gorkshnath H. and Bhopale, Somnath R. and More, Mahendra A. and Late, Dattatray J.} } @article {46915, title = {Nanoporous reduced graphene oxide and polymer composites as efficient counter electrodes in dye-sensitized solar cells}, journal = {ACS Applied Electronic Materials}, volume = {2}, year = {2020}, month = {MAR}, pages = {626-634}, type = {Article}, abstract = {

The introduction of an efficient and precious platinum (Pt) free counter electrode (CE) for dye-sensitized solar cells (DSSCs) is an important aspect to address. In this report, we have employed nanoporous reduced graphene oxide (PG) containing PEDOT:PSS-PG composite on FTO substrate as CEs, which have shown excellent diffusion of I-3(-), remarkable photocatalytic activity, and better device performance along with desired stability. The investigated cathode material has been prepared by mixing PGs and highly conducting PEDOT:PSS. Experimental measurements and analyses such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and so on indicate that PEDOT:PSS-PG is a promising cathode material for a Pt-free CE in DSSCs. EIS indicates that the PEDOT:PSS-PGs have lower interfacial charge-transfer resistance because of their high electrical conductivity and superior electrocatalytic activity. The achieved photoconversion efficiency (eta) of a DSSC employing the Pt-free PEDOT:PSS-PG/FTO CE is 9.57\%, which is found to be comparable to that of Pt/FTO CE based DSSC (9.64\%) under a simulated solar light illumination of 100 mW/cm(2).

}, keywords = {counter electrode, Dye-sensitized solar cells, electrocatalytic activity, PEDOT:PSS, Reduced graphene oxide}, issn = {2637-6113}, doi = {10.1021/acsaelm.9b00593}, author = {Sudhakar, Vediappan and Singh, Anup Kumar and Chini, Mrinmoy Kumar} }