@article {45931, title = {Chemically chargeable photo battery}, journal = {Journal of Physical Chemistry C}, volume = {119}, year = {2015}, month = {JUN }, pages = {14010-14016}, type = {Article}, abstract = {

Here we show a surrogate strategy for power production, wherein light is used to actuate a discharge Chemistry in the cathode of an aqueous rechargeable battery (ARB). The proposed photo battery consists of a titaninm nitride photoanode, promising. cathode:material iron(III) hexacyanoferrate(II) as the battery active species, and Na2S2O8 as the chemical charging agent The photo battery delivered negligible capacity in the dark and the capacity shot up to 77.8 mAh/g when artificially shined light, confirming that the battery chemistry is light driven. In the ambient light, the device retained 72\% of its artificial light discharge capacity with a stable cycling for more than 100 cycles. Further, an unprecedented means for charging the battery rapidly is presented using Na2S2O8 and it revitalized the battery in 30 s without any external bias. This methodology of expending a photoanode extends to a battery that is free from dissolution of active materials, irreversible structural changes, spontaneous deinsertion reactions, and safety concerns commonly encountered in the state of the art anode materials in ARBs. Apart from bringing out a sustainable way for power production, this device opens up avenues for charging the battery in the likely events of electrical input unavailability, while solving the critcial issues of longer charging time and higher charging voltage.

}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.5b02871}, author = {Thimmappa, Ravikumar and Paswan, Bhuneshwar and Gaikwad, Pramod and Devendrachari, Mruthyunjayachari Chattanahalli and Kotresh, Harish Makri Nimbegondi and Mohan, Ramsundar Rani and Alias, Joy Pattayil and Thotiyl, Musthafa Ottakam} } @article { ISI:000369515700086, title = {Solution chemistry-based nano-structuring of copper dendrites for efficient use in catalysis and superhydrophobic surfaces}, journal = {RSC Advances}, volume = {6}, number = {10}, year = {2016}, month = {JAN}, pages = {8416-8430}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Despite their performance and economic advantages over Ag and Au, there have been no focused research efforts on the nano-structuring of Cu dendrites with respect to fine-tuning their structure/morphology towards the efficiency enhancement of suitable applications. Reported here is a simple, versatile, environmentally-friendly and galvanic replacement reaction-based solution chemistry methodology to synthesize highly nano-structured copper dendrites targeted towards the efficiency enhancement of desired applications. Herein, copper is deposited galvanically on an Al foil in the presence of NaCl/HCl, wherein the chloride anions augment an uninterrupted replacement reaction. The growth process of Cu dendrites has been probed in detail. The presence of acid, the type of Cu2+ precursor salt, the Cu2+ ion concentration, the surfactant concentration and the reaction temperature are all demonstrated to provide useful means of modulating the surface structure/morphology of the dendrites. Notably, dendrites formed in the presence of acid are found to be highly nano-structured. Moreover, it is also found that the morphology/structure of the obtained Cu deposit depends considerably upon the choice of the Cu2+ precursor salt, a parameter that has been completely overlooked in the past. The acid-induced nano-structuring of the dendrites is exploited for enhancing their efficiency in the catalytic reduction of para-nitrophenol and for fabricating self-cleaning superhydrophobic surfaces. These nano-structured dendrites are demonstrated to have the highest ever normalized rate constant for the catalytic reduction reaction. Superhydrophobic surfaces fabricated using these dendrites demonstrate excellent self-cleaning abilities, showing a high contact angle (159 degrees) with low contact angle hysteresis (2 degrees). This facile synthetic strategy for the fabrication of highly nano-structured Cu dendrites is expected to open up avenues for the production of Cu-based low-cost functional nano/micro-materials.

}, issn = {2046-2069}, doi = {10.1039/c5ra22683j}, author = {Bakthavatsalam, Rangarajan and Ghosh, Subrata and Biswas, Ratul Kumar and Saxena, Aayushi and Raja, Alagar and Thotiyl, Musthafa Ottakam and Wadhai, Sandip and Banpurkar, Arun G. and Kundu, Janardan} } @article {46925, title = {Geometrical isomerism directed electrochemical sensing}, journal = {Analytical Chemistry}, volume = {92}, year = {2020}, month = {MAR}, pages = {4541-4547}, type = {Article}, abstract = {

We report the independent role of isomerism of secondary sphere substituents over their nature, a factor often overlooked in molecular electrocatalysis pertaining to electrochemical sensing, by establishing that isomerism redefines the electronic structure at the catalytic reaction center via geometrical factors. UV-vis spectroscopy and X-ray photoelectron spectroscopy suggest that a substituent{\textquoteright}s isomerism in molecular catalysts conjoins molecular planarity and catalytic activation through competing field effects and resonance effects. As a classical example, we demonstrate the influence of isomerism of the -NO2 substituents for the electrocatalytic multi electron oxidation of As(III), a potentially important electrochemical pathway for water remediation and arsenic detection. The isomerism dependent oxidative activation of catalytic center leads to a nonprecious molecular catalyst capable for direct As(III) oxidation with an experimental detection limit close to WHO guidelines. This work opens up an unusual approach in analytical chemistry for developing various sensing platforms for challenging chemical and electrochemical reactions.

}, issn = {0003-2700}, doi = {10.1021/acs.analchem.9b05753}, author = {Kottaichamy, Alagar Raja and Begum, Shabbah and Devendrachari, Mruthyunjayachar Chattanahalli and Bhat, Zahid Manzoor and Thimmappa, Ravikumar and Kotresh, Harish Makri Nimbegondi and Vinod, Chathakudath Prabhakaran and Thotiyl, Musthafa Ottakam} } @article {47011, title = {Unprecedented isomerism-activity relation in molecular electrocatalysis}, journal = {Journal of Physical Chemistry Letters}, volume = {11}, year = {2020}, month = {JAN }, pages = {263-271}, type = {Article}, abstract = {

The role of electrocatalysts in energy storage/conversion, biomedical and environmental sectors, green chemistry, and much more has generated enormous interest in comprehending their structure-activity relations. While targeting the surface-to-volume ratio, exposing reactive crystal planes and interfacial modifications are time-tested considerations for activating metallic catalysts; it is primarily by substitution in molecular electrocatalysts. This account draws the distinction between a substituent{\textquoteright}s chemical identity and isomerism, when regioisomerism of the -NO2 substituent is conferred at the {\textquoteleft}{\textquoteleft}alpha{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}beta{\textquoteright}{\textquoteright} positions on the macrocycle of cobalt phthalocyanines. Spectroscopic analysis and theoretical calculations establish that the beta isomer accumulates catalytically active intermediates via a cumulative influence of inductive and resonance effects. However, the field effect in the alpha isomer restricts this activation due to a vanishing resonance effect. The demonstration of the distinct role of isomerism in substituted molecular electrocatalysts for reactions ranging from energy conversion to biosensing highlights that isomerism of the substituents makes an independent contribution to electrocatalysis over its chemical identity.

}, issn = {1948-7185}, doi = {10.1021/acs.jpclett.9b02689}, author = {Kottaichamy, Alagar Raja and Begum, Shabbah and Nazrulla, Mohammed Azeezulla and Dargily, Neethu Christudas and Devendrachari, Mruthyunjayachari Chattanahalli and Bhat, Zahid Manzoor and Thimmappa, Ravikumar and Kotresh, Harish Makri Nimbegondi and Vinod, Chathakudath Prabhakaran and Thotiyl, Musthafa Ottakam} } @article {48125, title = {Regio-isomerism directed electrocatalysis for energy efficient zinc-air battery}, journal = {iScience}, volume = {25}, year = {2022}, month = {OCT }, pages = {105179}, type = {Article}, abstract = {

We have investigated the role of ligand isomerism in modulating the mechanisms and kinetics associated with charge/ discharge chemistry of an aqueous metal-air battery. The dominant electron-withdrawing inductive effect (-I effect) and the diminished electron-withdrawing resonance effect (-R effect) in the alpha-NO2 isomer noticeably diminishes the rate of oxygen reduction (ORR) and oxygen evolution reactions (OER) on the catalytic Co-center. In their beta-counterpart, the cumulative -I and -R effects noticeably enhance the OER and ORR kinetics on the same catalytic Co-center. Therefore, the regioisomerism of the -NO2 functionality amplifies the kinetics of ORR/OER without influencing their mechanistic pathways. When isomeric electrocatalysts are integrated to aid the charge chemistry of a Zn-air battery, the overpotential could be decreased by similar to 250mV with beta-NO2 isomer leading to a round-trip efficiency as high as 60\%. This work contributes to the design of novel molecular platforms to target the overall round-trip efficiency of energy storage and conversion devices.

}, doi = {10.1016/j.isci.2022.105179}, author = {Mukhopadhyay, Sanchayita and Devendrachari, Mruthyunjayachari Chattanahalli and Kanade, Sandeep C. and Vinod, Chathakudath Prabhakaran and Kotresh, Harish Makri Nimbegondi and Thotiyl, Musthafa Ottakam} } @article {48835, title = {Unprecedented energy storage in metal-organic complexes via constitutional isomerism}, journal = {Chemical Science}, volume = {14}, year = {2023}, month = {JUN}, pages = {6383-6392}, type = {Article}, abstract = {

The essence of any electrochemical system is engraved in its electrical double layer (EDL), and we report its unprecedented reorganization by the structural isomerism of molecules, with a direct consequence on their energy storage capability. Electrochemical and spectroscopic analyses in combination with computational and modelling studies demonstrate that an attractive field-effect due to the molecule{\textquoteright}s structural-isomerism, in contrast to a repulsive field-effect, spatially screens the ion-ion coulombic repulsions in the EDL and reconfigures the local density of anions. In a laboratory-level prototype supercapacitor, those with beta-structural isomerism exhibit nearly 6-times elevated energy storage compared to the state-of-the-art electrodes, by delivering similar to 535 F g(-1) at 1 A g(-1) while maintaining high performance metrics even at a rate as high as 50 A g(-1). The elucidation of the decisive role of structural isomerism in reconfiguring the electrified interface represents a major step forward in understanding the electrodics of molecular platforms.

}, issn = {2041-6520}, doi = {10.1039/d3sc01692g}, author = {Kottaichamy, Alagar Raja and Deebansok, Siraprapha and Deng, Jie and Nazrulla, Mohammed Azeezulla and Zhu, Yachao and Bhat, Zahid Manzoor and Devendrachari, Mruthyunjayachari Chattanahalli and Vinod, Chathakudath Prabhakaran and Kotresh, Harish Makri Nimbegondi and Fontaine, Olivier and Thotiyl, Musthafa Ottakam} }