Author
Kothandaraman Ramanujam
Other affiliations: Michigan State University
Bio: Kothandaraman Ramanujam is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Catalysis & Chemistry. The author has an hindex of 12, co-authored 67 publications receiving 544 citations. Previous affiliations of Kothandaraman Ramanujam include Michigan State University.
Topics: Catalysis, Chemistry, Materials science, Electrochemistry, Electrode
Papers
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TL;DR: In this article, two pyrene-carbazole dyes bearing single bond (PC1) and double bond spacer (PC2) linkers and cyano-acrylic acid as an acceptor were synthesized.
Abstract: Both carbazole and pyrene are electron-rich aromatic systems and are expected to be potential donors when used in a push–pull dye architecture in the field of DSSC technology. Herein, two novel pyrene–carbazole dyes bearing single bond (PC1) and double bond (PC2) linkers and cyano-acrylic acid as an acceptor were synthesized. The dye with a double bond spacer (PC2) in the presence of CDCA achieved an improved power conversion efficiency of 6.30% with a short circuit current of 11.59 mA cm−2, open circuit potential (VOC) of 0.80 V, and a fill factor of 0.68 under standard global AM 1.5G solar conditions. Cyclic voltammetry and density functional theory studies indicate that the incorporation of two donors improved the ease of oxidation of the dyes, which resulted in a high VOC. Despite having a rigid single bond, the charge transfer of the PC1 dye is found to be poor, which affected the photovoltaic performance. The dihedral angle measured at each joint of the optimized dye indicated that PC2 exhibits excellent intramolecular charge transfer due to the near planarity in the structure. Besides, the high electron lifetime in the excited state of PC2 makes it the best performer among the three dyes studied.
8 citations
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TL;DR: In this paper, a series of twelve (donor-π-linker) 2-Ancillary Acceptor-Acceptor ((D-π)2-An-A)) based metal-free organic dyes comprising BORON dipyrromethane (BODIPY) moiety as an ancillary acceptor (An) were designed to fine-tune the panchromatic behavior of BODIPy dyes.
Abstract: Small molecules having an absorption band beyond 750 nm for DSSC applications are scarce in the literature. Derivatives of boron dipyrromethane (BODIPY) are popular fluorophores in life sciences and hence used in fluorescent microscopy for staining different intracellular organelles, and BODIPY-based dye molecules have been known for the strong absorption in the visible and near IR regions. A series of twelve (Donor-π-linker)2-Ancillary Acceptor-Acceptor ((D-π)2-An-A)) based metal-free organic dyes comprising BODIPY moiety as an ancillary acceptor (An) were designed to fine-tune the panchromatic behavior of BODIPY dyes. Based on the density-functional theory (DFT) and time-dependent DFT, the photophysical and photoelectrochemical properties of the dyes were investigated. To convey the objective of the work, several photovoltaic parameters, such as dye regeneration driving force (ΔGreg), reorganization energy (Λ), chemical reactivity parameters, dye adsorption energy ( E a d s ), and the density of states were calculated to justify the suitability of the dyes for the DSSCs application. This study identified six dyes with carbazole and phenothiazine-based donors as DSSC suitable panchromatic dyes.
8 citations
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07 Aug 20197 citations
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7 citations
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TL;DR: This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core-shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts and metal-free catalysts.
Abstract: The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.
2,964 citations
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TL;DR: In this review, the recent advances in the application of MOFs in heterogeneous catalysis are discussed and the personal view on future research directions is wrapped up.
Abstract: More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...
772 citations
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TL;DR: This review describes the imprinted polymer production processes, the techniques used for reporting, and the applications of the reported sensors, including those designed to detect toxic chemicals, toxins in foods, drugs, explosives, and pathogens.
Abstract: Molecularly imprinted polymers are synthetic receptors for a targeted molecule. As such, they are analogues of the natural antibody–antigen systems. In this review, after a recounting of the early history of the general field, we specifically focus on the application of these polymers as sensors. In these applications, the polymers are paired with a reporting system, which may be electrical, electrochemical, optical, or gravimetric. The presence of the targeted molecule effects a change in the reporting agent, and a calibrated quantity of the target is recorded. In this review, we describe the imprinted polymer production processes, the techniques used for reporting, and the applications of the reported sensors. A brief survey of recent applications to gas-phase sensing is included, but the focus is primarily on the development of sensors for targets in solution. Included among the applications are those designed to detect toxic chemicals, toxins in foods, drugs, explosives, and pathogens. The application...
749 citations
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TL;DR: A comprehensive review of recent advances in the field of oxygen reduction electrocatalysis utilizing nonprecious metal catalysts is presented and suggestions and direction for future research to develop and understand NPM catalysts with enhanced ORR activity are provided.
Abstract: A comprehensive review of recent advances in the field of oxygen reduction electrocatalysis utilizing nonprecious metal (NPM) catalysts is presented Progress in the synthesis and characterization of pyrolyzed catalysts, based primarily on the transition metals Fe and Co with sources of N and C, is summarized Several synthetic strategies to improve the catalytic activity for the oxygen reduction reaction (ORR) are highlighted Recent work to explain the active-site structures and the ORR mechanism on pyrolyzed NPM catalysts is discussed Additionally, the recent application of Cu-based catalysts for the ORR is reviewed Suggestions and direction for future research to develop and understand NPM catalysts with enhanced ORR activity are provided
591 citations
17 Feb 2006
TL;DR: In this paper, the authors compared the performance of carbon nanotubes (MWNTs) and Vulcan XC-72 in terms of surface oxide formation and 30% lower corrosion current.
Abstract: Abstract Electrochemical surface oxidation of carbon black Vulcan XC-72 and multiwalled carbon nanotube (MWNT) has been compared following potentiostatic treatments up to 168 h under condition simulating PEMFC cathode environment (60 °C, N2 purged 0.5 M H2SO4, and a constant potential of 0.9 V). The subsequent electrochemical characterization at different treatment time intervals suggests that MWNT is electrochemically more stable than Vulcan XC-72 with less surface oxide formation and 30% lower corrosion current under the investigated condition. As a result of high corrosion resistance, MWNT shows lower loss of Pt surface area and oxygen reduction reaction activity when used as fuel cell catalyst support.
536 citations