A Defect-Engineered High-Entropy Alloy (Al–Cu–Fe–Ni–Ti) Unlocks Enhanced Hydrogen Evolution Performance Yogesh Kumar Yadav, Moumita Kotal, Caique C. de Oliveira, Guilherme Dariani, Chandra Sekhar Tiwary, Pedro Alves da Silva Autreto, Mohammad Abu Shaz, Nilay Krishna Mukhopadhyay, Thakur Prasad Yadav ACS Applied Energy Materials, 2026 High-entropy alloys (HEAs), known for their inherent compositional flexibility, tunable electronic structure, and excellent structural stability, have emerged as promising alternatives to noble-metal electrocatalysts. Nevertheless, their catalytic performance toward the alkaline hydrogen evolution reaction (HER) is often limited by insufficient active site exposure and suboptimal electronic modulation. Herein, we introduce a defect-engineering strategy to unlock the intrinsic catalytic activity of a non-noble Al–Cu–Fe–Ni–Ti HEA. A systematic comparison between high-energy mechanically alloyed and induction-melted HEAs reveals that synthesis-driven structural characteristics critically influence the HER activity. The mechanically alloyed HEA (HEA-1) exhibits a defect-rich microstructure, an enlarged electrochemical surface area (∼9.1 cm2 compared to 8.36 cm2 for HEA-2), and accelerated charge-transfer kinetics, resulting in enhanced HER performance with an onset potential of 230 mV, an overpotential of 301 mV at 10 mA cm–2, a Tafel slope of 130 mV dec–1, and prolonged stability even at a current density of 19.5 mA cm–2, thereby outperforming the melted counterpart (HEA-2). Density functional theory (DFT) calculations further suggest that Ni/Cu-coordinated sites and local atomic clustering are responsible for optimizing hydrogen binding. Collectively, the findings highlight the prospect of mechanically alloyed Al–Cu–Fe–Ni–Ti HEAs as robust and effective catalysts for electrocatalytic hydrogen evolution reaction.
Green Graphene Reinforcement to Enhance Mechanical and Wear Performance of Styrene–Butadiene Rubber-Based Composites Himanshu Singh, Anu Verma, Surya Prasanth Vadapalli, Moumita Kotal, Bidus Kanti Das, Chandra SekharTiwary, Jayanta Bhattacharya Journal of Applied Polymer Science, 2025 Here, we investigate the transformative potential of incorporating Green Graphene (GG) derived from remnant agricultural biomass (RAB) into styrene–butadiene rubber (SBR) formulations for the development of sustainable additives for tires. GG serves as a sustainable reinforcement material, exhibiting the capability to improve the mechanical, wear, and thermal degradation properties of SBR. The incorporation of GG into the SBR matrix results in astonishing improvements: resilience by 440.44%, toughness by 326.91%, tensile strength by 253.15%, yield strength by 313.33%, Young's modulus by 205.90%, elongation by 138.84%, and hardness by 148%. Furthermore, it leads to a decrease in nanoscratch depth, a 52.68% reduction in the coefficient of friction during sliding wear, a 22.38% improvement in hydrophobicity, and a 27% enhancement in thermal stability of the GG/SBR composites. These compelling performance enhancements of GG/SBR composites aim to provide a comprehensive understanding of the synergistic effects of GG and SBR rubber—shedding light on their combined potential. The outcomes from this investigation contribute valuable insights into the development of environmentally conscious green materials, writing the path for the evolution of the industry toward a greener and resilient future.
Hydrogen evolution reactions using 3D printed composites of copper with graphene and hexagonal boron nitride Rakesh Das, Raphael Benjamim, Moumita Kotal, Leonardo Machado, Douglas S. Galvao, Chandra Sekhar Tiwary Chemical Communications, 2025 Scalable 3D-printed Cu-based composites with uniformly distributed graphene exhibit superior HER performance, featuring optimized porosity and interface engineering, enhanced charge transport, and exceptional long-term stability.
Metal–Organic Framework-Derived Graphitic Nanoribbons Anchored on Graphene for Electroionic Artificial Muscles Moumita Kotal, Rassoul Tabassian, Sandipan Roy, Saewoong Oh, Il‐Kwon Oh Advanced Functional Materials, 2020 Abstract To achieve large bending displacement and fast response time under ultralow input voltages, as well as improved durability, advanced high‐performance ionic actuators still face crucial design challenges that must be resolved. Here, hierarchically porous and unzipped graphitic nanoribbons anchored on graphene as an efficient electrode material for high‐performance electroionic artificial muscles are reported. Using controlled solvothermal and pyrolysis methods, nanoarchitectured carbon is derived from a self‐templated potassium‐based metal–organic frameworks–graphene hybrid. The newly designed ionic actuator demonstrates excellent actuation performance, including large bending displacement (17.4 mm) and a strain difference of 0.51% at 0.5 V AC input, very fast response time (700 ms) at 0.5 V DC input, wide frequency response (0.1–15 Hz), and excellent cycling stability (92%) after 25 000 cycles without any delamination of electrodes under continuous electrical operation. The breakthrough in actuation performance mainly stems from the unzipping of hollow nanorods to hierarchical porous graphitic nanoribbons anchored on graphene with the enlarged surface area, large pore volume, stronger mechanical integrity, and emerging charge storage and transport ability. Further, the electroionic actuator shows promise when applied in the demonstration of a biomimicking Venus flytrap.
Graphenelated Cobalt Nanoparticle Embedded Nitrogen-Doped Carbon Nanotubes for Efficient Visible-Light Photocatalysis Moumita Kotal, Aashima Sharma, Sonu Jakhar, Vinit Mishra, Sandipan Roy, Subash Chandra Sahoo, Harish K. Sharma, Surinder Kumar Mehta Crystal Growth and Design, 2020 Visible-light-assisted photocatalysis for the degradation of organic pollutants has recently become an efficient green approach in the field of environmental pollution abatement. Herein, graphene-templated zeolite-imidazolate framework (ZIF-67) derived, Co nanoparticle embedded, nitrogen-doped carbon nanotubes (G-Co-NCNTs) have been developed as a promising, inexpensive, high-yield photocatalyst to decompose reactive black 5 (RB5) under visible light irradiation. Morphology and structural characterization studies revealed that the growth of NCNTs along with pyridinic N content and the abundance of meso-micropores were greater in G-Co-NCNT than in Co-NCNT itself, suggesting the importance of graphene for in situ growth of ZIF-67 on GO. DRS study reveals that G-Co-NCNT exhibited low optical band gap (∼2.9 eV), assisting in the promotion of photoresponse behavior. The photocatalytic activity of our designed G-Co-NCNT hybrid showed excellent dye degradation ability (98%) after 60 min with a wide range of pH tolerance and promising reusability even after five cycles (93%) under visible light, while Co-NCNT demonstrated only about 62% dye degradation, further implying the importance of graphene and oriented NCNTs for dye degradation. Therefore, the G-Co-NCNT hybrid could be used as an efficient photocatalyst for the remediation of organic pollutants in wastewater.
Mechanochemical Synthesis of a New Triptycene-Based Imine-Linked Covalent Organic Polymer for Degradation of Organic Dye Kawal Preet, Girish Gupta, Moumita Kotal, Sushil Kumar Kansal, Deepak B. Salunke, Harish K. Sharma, Subash Chandra Sahoo, Pascal Van Der Voort, Sandipan Roy Crystal Growth and Design, 2019 In the present work, a novel triptycene-based imine-linked covalent organic polymer (TP-COP) was designed and synthesized via room-temperature, solvent-free mechanochemical grinding. The as-synthesized TP-COP material was fully characterized by Fourier transform infrared spectroscopy, solid-state NMR, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller method, thermogravimetric analysis, diffuse reflectance spectroscopy (DRS), and electron paramagnetic resonance (EPR). The HRTEM image of TP-COP clearly indicates the presence of graphene-like layered morphology (exfoliated layers). The DRS study reveals that TP-COP exhibited a low optical band gap value of 2.49 eV, implying its semiconducting nature. Further, the EPR study confirmed the semiconducting behavior of TP-COP through the generation of free radicals. These findings suggest that TP-COP could be used as an efficient photocatayst for the degradation of organic dye (RhB...
Collectively Exhaustive Electrodes Based on Covalent Organic Framework and Antagonistic Co-Doping for Electroactive Ionic Artificial Muscles Sandipan Roy, Jaehwan Kim, Moumita Kotal, Rassoul Tabassian, Kwang J. Kim, Il‐Kwon Oh Advanced Functional Materials, 2019 Abstract In this study, high‐performance ionic soft actuators are developed for the first time using collectively exhaustive boron and sulfur co‐doped porous carbon electrodes (BS‐COF‐Cs), derived from thiophene‐based boronate‐linked covalent organic framework (T‐COF) as a template. The one‐electron deficiency of boron compared to carbon leads to the generation of hole charge carriers, while sulfur, owing to its high electron density, creates electron carriers in BS‐COF‐C electrodes. This antagonistic functionality of BS‐COF‐C electrodes assists the charge‐transfer rate, leading to fast charge separation in the developed ionic soft actuator under alternating current input signals. Furthermore, the hierarchical porosity, high surface area, and synergistic effect of co‐doping of the BS‐COF‐Cs play crucial roles in offering effective interaction of BS‐COF‐Cs with poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), leading to the generation of high electro‐chemo‐mechanical performance of the corresponding composite electrodes. Finally, the developed ionic soft actuator based on the BS‐COF‐C electrode exhibits large bending strain (0.62%), excellent durability (90% retention for 6 hours under operation), and 2.7 times higher bending displacement than PEDOT:PSS under extremely low harmonic input of 0.5 V. This study reveals that the antagonistic functionality of heteroatom co‐doped electrodes plays a crucial role in accelerating the actuation performance of ionic artificial muscles.
Electroactive Artificial Muscles Based on Functionally Antagonistic Core–Shell Polymer Electrolyte Derived from PS-b-PSS Block Copolymer Van Hiep Nguyen, Jaehwan Kim, Rassoul Tabassian, Moumita Kotal, Kiwoo Jun, Jung‐Hwan Oh, Ji‐Myeong Son, Muhammad Taha Manzoor, Kwang Jin Kim, Il‐Kwon Oh Advanced Science, 2019 Electroactive ionic soft actuators, a type of artificial muscles containing a polymer electrolyte membrane sandwiched between two electrodes, have been intensively investigated owing to their potential applications to bioinspired soft robotics, wearable electronics, and active biomedical devices. However, the design and synthesis of an efficient polymer electrolyte suitable for ion migration have been major challenges in developing high‐performance ionic soft actuators. Herein, a highly bendable ionic soft actuator based on an unprecedented block copolymer is reported, i.e., polystyrene‐b‐poly(1‐ethyl‐3‐methylimidazolium‐4‐styrenesulfonate) (PS‐b‐PSS‐EMIm), with a functionally antagonistic core–shell architecture that is specifically designed as an ionic exchangeable polymer electrolyte. The corresponding actuator shows exceptionally good actuation performance, with a high displacement of 8.22 mm at an ultralow voltage of 0.5 V, a fast rise time of 5 s, and excellent durability over 14 000 cycles. It is envisaged that the development of this high‐performance ionic soft actuator could contribute to the progress toward the realization of the aforementioned applications. Furthermore, the procedure described herein can also be applied for developing novel polymer electrolytes related to solid‐state lithium batteries and fuel cells.
Recent advances on preparation, properties and applications of polyurethane nanocomposites Nanocomposites Materials Manufacturing and Engineering, 2013
Conversion of agricultural waste into green–white graphene hybrids for high-performance textiles https://www.sciencedirect.com/science/article/abs/pii/S138589472604129X CST Moumita Kotal a 1 *, Guilherme da Silva Lopes Fabris b 1 , Surbhi ... Chemical Engineering Journal 538, 176668 , 2026 2026
Conversion of agricultural waste into green–white graphene hybrids for high-performance textiles M Kotal, GSL Fabris, S Slathia, A Shanu, R Das, B Ipaves, MLP Júnior, ... Chemical Engineering Journal, 176668 , 2026 2026
Transforming Discarded Thermoelectrics into High-Performance HER Catalysts GJ Usa, CC Oliveira, V Pal, S Sarkar, GB Feyisa, M Kotal, E Femiolu, ... arXiv preprint arXiv:2604.04718 , 2026 2026
Transforming Discarded Thermoelectrics into High-Performance HER Catalysts CC Oliveira, V Pal, S Sarkar, G Bekele Feyisa, M Kotal, E Femiolu, ... arXiv e-prints, arXiv: 2604.04718 , 2026 2026
A Defect-Engineered High-Entropy Alloy (Al–Cu–Fe–Ni–Ti) Unlocks Enhanced Hydrogen Evolution Performance YK Yadav, M Kotal, CC de Oliveira, G Dariani, CS Tiwary, PAS Autreto, ... ACS Applied Energy Materials 9 (7), 4052-4064 , 2026 2026
Green Graphene Reinforcement to Enhance Mechanical and Wear Performance of Styrene–Butadiene Rubber‐Based Composites H Singh, A Verma, SP Vadapalli, M Kotal, BK Das, C SekharTiwary, ... Journal of Applied Polymer Science 142 (38), e57492 , 2025 2025 Citations: 6
Hydrogen evolution reactions using 3D printed composites of copper with graphene and hexagonal boron nitride R Das, R Benjamim, M Kotal, L Machado, DS Galvao, CS Tiwary Chemical Communications 61 (50), 9039-9042 , 2025 2025 Citations: 4
Cathode materials for rechargeable lithium batteries: Recent progress and future prospects M Kotal, S Jakhar, S Roy, HK Sharma Journal of Energy Storage 47, 103534 , 2022 2022 Citations: 146
Electroionic Artificial Muscles: Metal–Organic Framework‐Derived Graphitic Nanoribbons Anchored on Graphene for Electroionic Artificial Muscles (Adv. Funct. Mater. 29/2020). M Kotal, R Tabassian, S Roy, S Oh, IK Oh Advanced Functional Materials 30 (29) , 2020 2020 Citations: 5
Metal–organic framework‐derived graphitic nanoribbons anchored on graphene for electroionic artificial muscles M Kotal, R Tabassian, S Roy, S Oh, IK Oh Advanced Functional Materials 30 (29), 1910326 , 2020 2020 Citations: 51
Graphene-templated cobalt nanoparticle embedded nitrogen-doped carbon nanotubes for efficient visible-light photocatalysis M Kotal, A Sharma, S Jakhar, V Mishra, S Roy, SC Sahoo, HK Sharma, ... Crystal Growth & Design 20 (7), 4627-4639 , 2020 2020 Citations: 46
Mechanochemical synthesis of a new triptycene-based imine-linked covalent organic polymer for degradation of organic dye K Preet, G Gupta, M Kotal, SK Kansal, DB Salunke, HK Sharma, ... Crystal Growth & Design 19 (5), 2525-2530 , 2019 2019 Citations: 66
Collectively exhaustive electrodes based on covalent organic framework and antagonistic Co‐doping for electroactive ionic artificial muscles S Roy, J Kim, M Kotal, R Tabassian, KJ Kim, IK Oh Advanced Functional Materials 29 (17), 1900161 , 2019 2019 Citations: 78
Electroactive Artificial Muscles Based on Functionally Antagonistic Core–Shell Polymer Electrolyte Derived from PS‐ b ‐PSS Block Copolymer VH Nguyen, J Kim, R Tabassian, M Kotal, K Jun, JH Oh, JM Son, ... Advanced Science 6 (5), 1801196 , 2019 2019 Citations: 50
Collectively exhaustive electrode for electro-active ionic artificial muscles based on covalent organic framework and antagonistic co-doping S Roy, J Kim, M Kotal, R Tabassian, KJ Kim, IK Oh Advanced Materials 29 (17) , 2019 2019
Design and Synthesis of PS-b-PSS Block Copolymer Electrolyte for Electroactive Artificial Muscles VH Nguyen, IK Oh, W Hwang, J Kim, R Tabassian, M Kotal, K Jun, J Oh, ... BAMN 2019 , 2019 2019
Molybdenum Disulfide Grown on Graphene as Electrodes for Ionic Artificial Muscles VH Nguyen, W Hwang, J Kim, R Tabassian, M Kotal, J Oh, J Son, ... BAMN 2019 , 2019 2019
Highly bendable ionic soft actuator based on nitrogen‐enriched 3D hetero‐nanostructure electrode M Kotal, J Kim, R Tabassian, S Roy, VH Nguyen, N Koratkar, IK Oh Advanced Functional Materials 28 (34), 1802464 , 2018 2018 Citations: 76
Electro-ionic Artificial Muscles based on Three-dimensional Graphene Nanostructures J Kim, SH Bae, IK Oh 2018 3rd International Conference on Composite Materials and Material … , 2018 2018
Actuators: Functionally Antagonistic Hybrid Electrode with Hollow Tubular Graphene Mesh and Nitrogen‐Doped Crumpled Graphene for High‐Performance Ionic Soft Actuators (Adv … R Tabassian, J Kim, VH Nguyen, M Kotal, IK Oh Advanced Functional Materials 28 (5), 1870033 , 2018 2018 Citations: 4
MOST CITED SCHOLAR PUBLICATIONS
Polymer nanocomposites from modified clays: Recent advances and challenges M Kotal, AK Bhowmick Progress in Polymer Science 51, 127-187 , 2015 2015 Citations: 760
Sulfur and Nitrogen Co‐Doped Graphene Electrodes for High‐Performance Ionic Artificial Muscles M Kotal, J Kim, KJ Kim, IK Oh Advanced Materials 28 (8), 1610-1615 , 2016 2016 Citations: 222
Polyaniline–carbon nanofiber composite by a chemical grafting approach and its supercapacitor application M Kotal, AK Thakur, AK Bhowmick ACS Applied Materials & Interfaces 5 (17), 8374-8386 , 2013 2013 Citations: 160
Cathode materials for rechargeable lithium batteries: Recent progress and future prospects M Kotal, S Jakhar, S Roy, HK Sharma Journal of Energy Storage 47, 103534 , 2022 2022 Citations: 146
Self-assembly and morphological control of three-dimensional macroporous architectures built of two-dimensional materials JE Kim, JH Oh, M Kotal, N Koratkar, IK Oh Nano Today 14, 100-123 , 2017 2017 Citations: 98
Thermoplastic polyurethane and nitrile butadiene rubber blends with layered double hydroxide nanocomposites by solution blending M Kotal, SK Srivastava, AK Bhowmick Polymer International 59 (1), 2-10 , 2010 2010 Citations: 98
Multifunctional hybrid materials based on carbon nanotube chemically bonded to reduced graphene oxide M Kotal, AK Bhowmick The Journal of Physical Chemistry C 117 (48), 25865-25875 , 2013 2013 Citations: 94
Soft but powerful artificial muscles based on 3D graphene–CNT–Ni heteronanostructures J Kim, SH Bae, M Kotal, T Stalbaum, KJ Kim, IK Oh Small 13 (31), 1701314 , 2017 2017 Citations: 88
Functionally Antagonistic hybrid electrode with hollow tubular graphene mesh and nitrogen‐doped crumpled graphene for high‐performance ionic soft actuators R Tabassian, J Kim, VH Nguyen, M Kotal, IK Oh Advanced Functional Materials 28 (5), 1705714 , 2018 2018 Citations: 85
Sulfur and nitrogen co-doped holey graphene aerogel for structurally resilient solid-state supercapacitors under high compressions M Kotal, H Kim, S Roy, IK Oh Journal of Materials Chemistry A 5 (33), 17253-17266 , 2017 2017 Citations: 82
Functionalized graphene with polymer as unique strategy in tailoring the properties of bromobutyl rubber nanocomposites M Kotal, SS Banerjee, AK Bhowmick Polymer 82, 121-132 , 2016 2016 Citations: 80
Collectively exhaustive electrodes based on covalent organic framework and antagonistic Co‐doping for electroactive ionic artificial muscles S Roy, J Kim, M Kotal, R Tabassian, KJ Kim, IK Oh Advanced Functional Materials 29 (17), 1900161 , 2019 2019 Citations: 78
Synthesis and characterization of polyurethane/Mg‐Al layered double hydroxide nanocomposites M Kotal, T Kuila, SK Srivastava, AK Bhowmick Journal of Applied Polymer Science 114 (5), 2691-2699 , 2009 2009 Citations: 77
Highly bendable ionic soft actuator based on nitrogen‐enriched 3D hetero‐nanostructure electrode M Kotal, J Kim, R Tabassian, S Roy, VH Nguyen, N Koratkar, IK Oh Advanced Functional Materials 28 (34), 1802464 , 2018 2018 Citations: 76
Enhancements in conductivity and thermal stabilities of polypyrrole/polyurethane nanoblends M Kotal, SK Srivastava, B Paramanik The Journal of Physical Chemistry C 115 (5), 1496-1505 , 2011 2011 Citations: 75
Mechanochemical synthesis of a new triptycene-based imine-linked covalent organic polymer for degradation of organic dye K Preet, G Gupta, M Kotal, SK Kansal, DB Salunke, HK Sharma, ... Crystal Growth & Design 19 (5), 2525-2530 , 2019 2019 Citations: 66
Defect engineering route to boron nitride quantum dots and edge-hydroxylated functionalization for bio-imaging JH Jung, M Kotal, MH Jang, J Lee, YH Cho, WJ Kim, IK Oh RSC advances 6 (77), 73939-73946 , 2016 2016 Citations: 60
Recent progress in multifunctional graphene aerogels M Kotal, J Kim, J Oh, IK Oh Frontiers in Materials 3, 29 , 2016 2016 Citations: 56
Metal–organic framework‐derived graphitic nanoribbons anchored on graphene for electroionic artificial muscles M Kotal, R Tabassian, S Roy, S Oh, IK Oh Advanced Functional Materials 30 (29), 1910326 , 2020 2020 Citations: 51
Electroactive Artificial Muscles Based on Functionally Antagonistic Core–Shell Polymer Electrolyte Derived from PS‐ b ‐PSS Block Copolymer VH Nguyen, J Kim, R Tabassian, M Kotal, K Jun, JH Oh, JM Son, ... Advanced Science 6 (5), 1801196 , 2019 2019 Citations: 50