@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 {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} } @article {48992, title = {Electrochemical energy storage in an organic supercapacitor via a non-electrochemical proton charge assembly}, journal = {Chemical Science}, volume = {15}, year = {2024}, month = {JAN }, pages = {1726-1735}, type = {Article}, abstract = {

Contrary to conventional beliefs, we show how a functional ligand that does not exhibit any redox activity elevates the charge storage capability of an electric double layer via a proton charge assembly. Compared to an unsubstituted ligand, a non-redox active carboxy ligand demonstrated nearly a 4-fold increase in charge storage, impressive capacitive retention even at a rate of 900C, and approximately a 2-fold decrease in leakage currents with an enhancement in energy density up to approximately 70\% via a non-electrochemical route of proton charge assembly. Generalizability of these findings is presented with various non-redox active functional units that can undergo proton charge assembly in the ligand. This demonstration of non-redox active functional units enriching supercapacitive charge storage via proton charge assembly contributes to the rational design of ligands for energy storage applications.

}, issn = {2041-6520}, doi = {10.1039/d3sc05639b}, author = {Mukhopadhyay, Sanchayita and Kottaichamy, Alagar Raja and Devendrachari, Mruthyunjayachari Chattanahalli and Mendhe, Rahul Mahadeo and Kotresh, Harish Makri Nimbegondi and Vinod, Chathakudath Prabhakaran and Thotiyl, Musthafa Ottakam} } @article {49116, title = {Fuel from waste: electrosynthesizing ammonia directly from agricultural digestate through ligand isomerization}, journal = {Green Chemistry}, volume = {26}, year = {2024}, month = {JUN}, pages = {6490-6500}, type = {Article}, abstract = {

We demonstrate that the catalytic metal centre for ammonia production can be selectively activated with only a slight alteration in ligand isomerization (alpha and beta isomers), making it practical and effective even for agricultural effluents. With almost 90\% faradaic efficiency, the beta isomer generates approximately 0.64 mg h-1 cm-2 of ammonia. Energy-efficient ammonia recovery is made possible by the interfacial proton charge assembly that beta-isomerization creates, which attracts the reacting nitrate and repels the competing hydronium ions. With minimal energy consumption, this isomerization approach can interconvert agricultural effluents into ammonia fuel, reaching up to 84\% of its theoretical yield and maintaining stability over 100 hours of continuous electrolysis. Ligand isomerization driven ammonia electrosynthesis from agricultural waste water.

}, issn = {1463-9262}, doi = {10.1039/d4gc00740a}, author = {Mendhe, Rahul Mahadeo and Mondal, Ritwik and Kottaichamy, Alagar Raja and Haridas, Akshay and Kotresh, Harish Makri Nimbegondi and Vinod, Chathakudath Prabhakaran and Thimmappa, Ravikumar and Thotiyl, Musthafa Ottakam} } @article {49261, title = {Ligand isomerization driven electrocatalytic switching}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {63}, year = {2024}, month = {JUL}, type = {Journal Article}, keywords = {Catalysts, CO2 reduction, O-2 REDUCTION, oxygen reduction}, issn = {1433-7851}, doi = {10.1002/anie.202405664}, author = {Kottaichamy, Alagar Raja and Nazrulla, Mohammed Azeezulla and Parmar, Muskan and Thimmappa, Ravikumar and Devendrachari, Mruthyunjayachari Chattanahalli and Vinod, Chathakudath Prabhakaran and Volokh, Michael and Kotresh, Harish Makri Nimbegondi and Shalom, Menny and Thotiyl, Musthafa Ottakam} } @article {49246, title = {Switchable molecular electrocatalysis}, journal = {CHEMICAL SCIENCE}, volume = {15}, year = {2024}, month = {AUG }, pages = {13262-13270}, type = {Journal Article}, keywords = {CO2 reduction, COBALT PHTHALOCYANINE, NANOPOROUS GOLD, oxygen reduction}, issn = {2041-6520}, doi = {10.1039/d4sc01284d}, author = {Dutt, Shifali and Kottaichamy, Alagar Raja and Dargily, Neethu Christudas and Mukhopadhyay, Sanchayita and Nayak, Bhojkumar and Devendrachari, Mruthyunjayachari Chattanhali and Vinod, Chatakudhath Prabakaran and Kotresh, Harish Makri Nimbegondi and Thotiyl, Musthafa Ottakam} } @article {49334, title = {Synergistic effects of the substrate-ligand interaction in metal-organic complexes on the de-electronation kinetics of a vitamin C fuel cell}, journal = {Dalton Transactions}, volume = {53}, year = {2024}, month = {AUG }, pages = {13384-13393}, type = {Article}, abstract = {

The rising demand for portable energy conversion devices has spurred the advancement of direct liquid fuel cells (DLFCs) employing fuels such as alcohol, ammonia, hydrazine, and vitamin C. In these devices, various precious metal platforms have been explored to increase the de-electronation kinetics and reduce catalyst poisoning, but with substantial cost implications. We demonstrate the crucial role of ligands in non-precious organometallic complexes in influencing the de-electronation kinetics of fuel molecules through a unique substrate-ligand synergistic interaction. This unique chemistry imparts electron deficiency at the catalytic metal center while simultaneously populating the ligand with an extensive proton charge assembly. This distinct substrate-ligand interaction enhances the DLFC performance by coulombically dragging the substrate with a distinct amplification in its de-electronation kinetics. By integrating this approach with a ferricyanide/ferrocyanide half-cell reaction, a precious metal-free vitamin C fuel cell is developed, which is capable of generating an open circuit voltage of similar to 950 mV, a peak power density of similar to 97 mW cm-2 at a peak current density of similar to 215 mA cm-2 with the performance metrics nearly 1.7 times higher than a precious metal based DLFC. This highlights the potential of the substrate-ligand synergy in the design of efficient molecular catalysts for energy conversion applications. A precious metal-free biomass fuel cell through substrate-ligand interactions.

}, issn = {1477-9226}, doi = {10.1039/d4dt01370k}, author = {Parmar, Muskan and Mukhopadhyay, Sanchayita and Mondal, Ritwik and Nayak, Bhojkumar and Dargily, Neethu Christudas and Kotresh, Harish Makri Nimbegondi and Vinod, Chathakudath Prabhakaran and Ottakam Thotiyl, Musthafa} }