Department of Chemistry

Indian Institute of Technology Hyderabad (IITH) is a premier institute of science and technology established in 2008. IITH has been consistently ranked in the&nbsp;<a href="https://iith.ac.in/reports/" rel="noopener noreferrer">top 10 institutes</a>&nbsp;in India for Engineering&nbsp;<a href="https://www.nirfindia.org/2021/EngineeringRanking.html" rel="noopener noreferrer" target="_blank">according to NIRF</a>&nbsp;making it one of the most coveted schools for science and technology in the country.

IITH offers&nbsp;<a href="https://iith.ac.in/academics/under-graduate/">undergraduate programs</a>&nbsp;in all the classical engineering disciplines, applied sciences, design, as well as several modern interdisciplinary areas. Students are given a flexibility to explore a broad set of areas, and potentially pursue a minor or double major in a discipline that is not their own. Students who wish to seek a deeper understanding of their own discipline are strongly encouraged to get involved in cutting-edge research with the help of a faculty to mentor them, and earn an Honors in their own field.

The very foundation of IIT Hyderabad is based on&nbsp;<a href="https://iith.ac.in/research/">research and innovation</a>. The vibrant research culture is evident from the number of patents and publications that IITH produces consistently every year. IITH offers&nbsp;<a href="https://iith.ac.in/academics/programmes-offered/">graduate programs</a>&nbsp;at both a masters, and a doctoral level, in several diverse areas. There are separate programs for technology, design, science, and liberal arts. The&nbsp;<a href="https://iith.ac.in/academics/post-graduate/">MTech program</a>&nbsp;is offered in various modes and durations to cater to the ever-growing need of postgraduate level professionals in the country.

IITH encourages and supports&nbsp;<a href="https://iic-iith.netlify.app/index.html" rel="noopener noreferrer" target="_blank">innovation and entrepreneurship</a>&nbsp;at every stage. The minor program in entrepreneurship is open to all students of IITH, and many of the courses are offered by industrialists who are entrepreneurs themselves. There are various&nbsp;<a href="https://iith.ac.in/research/centres-incubators/">innovation centers and incubators</a>&nbsp;that promote entrepreneurship and help mentor young innovators. IITH has been very successful in building tie-ups with leading academic institutions around the globe.

IITH enjoys a very special relationship with Japanese universities and industries that goes beyond academic and research collaborations. In fact, some of the iconic buildings in IITH campus will carry the signature of Japanese architecture.

IITH creates a unique holistic ecosystem for education that offers interactive learning, a very flexible academic structure, cutting-edge research, strong industry collaboration, and entrepreneurship. This is an environment which enables students and faculty to translate their dreams into realities.

IIT Hyderabad

Inhibiting the growth of dendrites, one of the most serious issues faced by zinc-ion batteries (ZIBs) is addressed by coating the Zn anode with a layer of poly(carbazole)-carbon nanotubes (PCz@CNTs) composite. The electrically conducting robust composite overlayer ensures that the Zn-deposition during charging cycles is homogeneous and completely free of any fiber-like growth. This is confirmed from the cross-sectional electron microscopy analysis of post-cycled PCz@CNTs@Zn electrode. A vanadium oxide nanorods-porous graphitic flakes (V6O13 NRs@PGFs) composite is used as a cathode. It has a large specific surface area, affording short ion-diffusion distances and many vacant sites thus permitting facile Zn2+ ion ingress and egress, is used. A remarkable performance results for the non-aqueous ZIB: V6O13 NRs@PGFs//PCz@CNTs@Zn with a capacity of 286 mAh g−1 after 300 cycles at 30 mA g−1 (with 98% capacity retention), energy density of ∼172 Wh kg−1 and a nominal voltage of 1.8 V. It is significantly enhanced compared to its analogous ZIB of V6O13 NRs@PGFs//Zn (193 mAh g−1, and 80% capacity retention). The PCzCNTs overlayer imparts long lifespan with nominal capacity fade, guarantees ultra-safe operation, is cost-effective and also easy to scale-up thus providing a solution that can be adapted to other metal-ion batteries free of dendrites and long term cycling stability. © 2023 Elsevier Ltd

World University root node

Composites Part B: Engineering

Dendrite growth inhibition in a V6O13 nanorods based non-aqueous Zn-ion battery by a scalable polycarbazole@Carbon nanotubes overlayer

Bandgap-engineered inorganic and hybrid halide perovskite (HP) films, nanocrystals, and quantum dots (PQDs) are promising for solar cells. Fluctuations of photoinduced electron transfer (PET) rates affect the interfacial charge separation efficiencies of such solar cells. Electron donor- or acceptor-doped perovskite samples help analyze PET and harvest photogenerated charge carriers efficiently. Therefore, PET in perovskite-based donor-acceptor (D-A) systems has received considerable attention. We analyzed the fluctuations of interfacial PET from MAPbBr3 or CsPbBr3 PQDs to classical electron acceptors such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 1,2,4,5-tetracyanobenzene (TCNB) at single-particle and ensemble levels. The significantly negative Gibbs free energy changes of PET estimated from the donor-acceptor redox potentials, the donor-acceptor sizes, and the solvent dielectric properties help us clarify the PET in the above D-A systems. The dynamic nature of PET is apparent from the decrease in photoluminescence (PL) lifetimes and PL photocounts of PQDs with an increase in the acceptor concentrations. Also, the acceptor radical anion spectrum helps us characterize the charge-separated states. Furthermore, the PL blinking time and PET rate fluctuations (108 to 107 s−1) provide us with single-molecule level information about interfacial PET in perovskites. © 2023 The Royal Society of Chemistry.

Nanoscale

Photoinduced interfacial electron transfer from perovskite quantum dots to molecular acceptors for solar cells

Lithium-ion capacitors were conceptualized to bridge the gap between high-energy lithium-ion batteries and high-power electric double-layer capacitors. The history behind the motivation, conceptualization, and development of LICs is studied thoroughly in this article. Since the inception of LICs, various mechanistically different types of lithium-ion capacitors have been assembled, further pushing the energy and power limitations. This perspective provides an outlook on the types of LICs that have evolved based on their construction, assembly, and mechanism. Furthermore, the different charge storage mechanisms involved in the LICs are studied, and how the pre-lithiation strategy affects the mechanism and deliverable energy of the device is analyzed. Further, the effect of the varying charge storage mechanism on the balance of energy-power output is outlined thoroughly with specific emphasis on feasibility and prospects of commercialization. Finally, the road map to commercialization of the LICs and the factors controlling the growth in the energy market space are carefully analyzed. © 2023 The Royal Society of Chemistry.

Sustainable Energy and Fuels

A perspective on the evolution and journey of different types of lithium-ion capacitors: mechanisms, energy-power balance, applicability, and commercialization

The composites of metal oxides and carbons are of research interest for improving the energy density of supercapacitors. In this work, we have demonstrated a simple one-pot hydrothermal synthesis method to prepare NiO nanorods followed by carbon framework decorated NiO nanorods (NiO@C). The NiO@C electrode showed an excellent specific capacitance of 1360 F g−1 compared to pristine NiO of 890 F g−1 at 1 A g−1 in a voltage range of 0.05 to 0.5 V in 1 M KOH electrolyte. The NiO@C electrodes showed excellent cycle stability over 10,000 cycles with 90 % capacitance retention. Asymmetric supercapacitors fabricated using corncob-derived activated carbon anode, and NiO@C cathode delivers a power density of 4574 W kg−1 at an energy density of 21.6 Wh kg−1. The enhanced capacitance of NiO@C material is due to the synergistic effect of the pseudocapacitive of NiO nanorods and the electric double-layer capacitance of the carbon matrix. Besides, the carbon framework facilitates quick charge acceptance, improved cycling stability, and rate capability. The cost-effective one-pot synthesis and eco-friendly NiO nanorods with easy electrode fabrication open opportunities for developing high-energy-density NiO-based supercapacitors. © 2023 Elsevier Ltd

Journal of Energy Storage

One pot synthesis of carbon decorated NiO nanorods as cathode materials for high-performance asymmetric supercapacitors

Dual carbon lithium-ion capacitors (LICs) are the next-generation hybrid energy storage devices that aim towards energy-power balanced applications. Thus, tuning the properties of the carbon electrode materials is a crucial step toward optimizing the device's performance. Herein, the effect of change in the microstructure of the carbon electrodes on the ion storage capacity and their consequent energy-power manifestation is investigated. The optimized carbonaceous anode calcined at 700 ⁰C delivers 290 mAh g−1 capacity after 1000 cycles at 1 A g−1. This superiority in performance is attributed to the formation of micron-size channels and mesopores for better ion transport and storage. In contrast, the activated carbon cathode delivers a capacitance of 118 F g−1 and retains 76% at the end of 5000 cycles. The LIC full cell with these electrode materials provides maximum energy of 120 Wh kg−1, a maximum power density of 20.7 kW kg−1 and cycles till 9000 cycles with ∼67% capacitance retention. The mechanistic control over the deliverable ion storage capacity is also analyzed for the LIC full cell. Furthermore, the lighting demonstration, self-discharge studies, leakage current, and electrochemical impedance are recorded to elucidate the practical feasibility and performance degradation mechanism of the coin-cell device. © 2023

Electrochimica Acta

Effect of varying carbon microstructures on the ion storage behavior of dual carbon lithium-ion capacitor

A coaxial dielectric barrier discharge (DBD) reactor was used to perform catalytic non-thermal plasma for CO2 conversion under ambient conditions. A systematic study was made to understand the role of basic oxides in activating weakly acidic CO2. For this purpose, MO/γ-Al2O3 (M = Mg, Ca, Sr, and Ba) catalysts were synthesized and integrated with the DBD reactor. The applied voltage was varied from 16 kV to 22 kV to determine the effect of applied voltage on CO2 conversion. Plasma discharge generates high-energy electrons that activate the basic oxides. Integration of basic metal oxides with the non-thermal plasma reactor resulted in a higher CO2 conversion. The adsorption of weakly acidic CO2 on the basic sites is responsible for the higher conversion of catalytic plasma reactor over plasma reactor alone. Among the basic metal oxides studied, SrO loaded γ-Al2O3 resulted in the best conversion, where CO2 conversion of ∼ 12% and energy efficiency of ∼ 1.46 mmol kJ−1 was attained at a power of 1.8 W. The concentration of O2 and O3 was measured during the reaction. The hybridized system's superior performance may be due to increased charge deposition and altered gas-phase chemistry because of catalyst integration. BOLSIG + software was used to compute the mean electron energies and electron energy distribution function for various packing conditions. © 2023 Elsevier B.V.

Department of Chemical Engineering

Chemical Engineering Journal

Basic metal oxide integrated DBD packed bed reactor for the decomposition of CO2

Biogas is a renewable energy produced due to the anaerobic decomposition of plants and animals. Biogas contains a high amount of methane (CH4), carbon dioxide (CO2), and trace amounts of hydrogen sulfide (H2S). It is naturally released in the environment, and the composition varies depending on the source it is generated. The primary focus of the study is to understand the influence of H2S on CH4 and CO2 conversion during syngas production. The effect of applied voltage on biogas reforming reaction with different dielectric materials (glass beads, γ-Al2O3, ZrO2, and quartz wool) packed in a discharge zone was investigated by using a dielectric barrier discharge (DBD) non-thermal plasma reactor. The influence of gas composition and packed bed on the efficiency of the biogas reforming reaction was investigated. After that, the biogas reforming reaction with packed dielectric material was performed without H2S and subsequently with H2S (blended with N2) while keeping the residence time constant. It was observed that H2S has a significant effect on the conversion. The CH4 conversion drastically dropped from 23% (without H2S) to 9% (with H2S), and CO2 conversion dropped from 18% to 11 % at 22 kV with quartz wool packed DBD. Energy efficiency decreased from 3.12 mmol/kJ (without H2S) to 1.78 mmol/kJ (with H2S) with glass beads packed DBD. Moreover, H2S has more effect on CH4 conversion than CO2. © 2023 Elsevier Ltd

Department of Physics

Biomass and Bioenergy

Biogas reforming to syngas in a DBD plasma reactor with dielectric materials packing: Effect of H2S on the conversion of CH4 and CO2

We report a series of Zn(II) and Cd(II) metal complexes [L12(ZnCl2)] (1), [L12(ZnBr2)] (2), [L12(CdCl2)] (3), [L12(CdI2)] (4), [L22(ZnCl2)] (5), [L22(ZnBr2)] (6), [L22(ZnI2)] (7), [L22(CdCl2)] (8), [L32(CdCl2)] (9) and [L42(ZnBr2)] (10), synthesized using various unsymmetrical aryl thiourea ligands: 1-(2,6-diisopropylphenyl)-3-phenylthiourea (L1), 1-mesityl-3-phenylthiourea (L2), 1-(2-fluorophenyl)-3-phenylthiourea (L3) and symmetrical 1,3-bis(2-fluorophenyl)thiourea (L4). The ligands and metal complexes were characterized by 1H, 13C{1H} NMR, FT-IR analysis. Solid-state structures of the zinc and cadmium metal complexes (1–8) were established using the single-crystal diffraction analysis technique. Furthermore, the catalytic activities of the Zn(II) complexes towards hydroboration of aldehydes and ketones (-C=O) as substrates were studied. Excellent yields of the corresponding boronate esters were achieved. © 2022 Wiley-VCH GmbH.

Zeitschrift fur Anorganische und Allgemeine Chemie

Synthesis, characterization and catalytic activities of Zn(II) and Cd(II) complexes supported by unsymmetrical aryl thiourea ligands

Substituted organoselenium compounds are crucial structural motifs in pharmaceutical molecules. Herein, we report a metal, oxidant, and base-free electrochemical approach to access 3-selenylindoles through an oxidative cyclization of 2-alkynylanilines with diselenides. This environmentally friendly approach demonstrates a wide range of substrate scope under mild reaction conditions in an electrochemical undivided cell setup. © 2023 The Royal Society of Chemistry.

Chemical Communications

An electrochemical cascade process: synthesis of 3-selenylindoles from 2-alkynylanilines with diselenides

We report the structure and dynamics of layered water structure near a bilayer heterosurface using classical molecular dynamics simulations and network graph theory. The heterosurfaces of our choice are technologically essential and well-studied hexagonal boron nitride (h-BN) and graphitic carbon nitride (g-C3N4). Starting with the water density distribution profile, we have studied different hydrogen bondings (HBs) associated with distance and angle distributions and correlated them with the HB count, followed by the investigations of dynamic properties. We realize the oddity while corresponding to the tetrahedral order parameter (TOP), HB donor/acceptor count, and HB lifetime. A quantitative gap is observed between the TOP and HB counts, and we perceive another structural factor playing a significant role. We observe a 2D sheetlike arrangement of hydrogen-bonded water molecules, namely, 2D-HB, in the interfacial layer instead of 3D tetrahedral arrangements. 2D-HB qualitatively acts as a key descriptor of the hydrophobicity of the interface. The probability of higher TOP among the interfacial layer water molecules is less for h-BN compared to g-C3N4. However, the per-water HBs for both the heterosurfaces remain indistinguishable, implying the existence of another significant physical factor related to HB. Hence, 2D-HB serves as a deciding factor. In the case of h-BN, water molecules in the first layer form extended 2D sheets compared to the second and bulk, which is not a scenario for g-C3N4. Following the network graph theory, we calculated the temporal evolution of the maximum number of water molecules connected in a single network. The layer 1 water molecules have slower orientational dynamics, higher HB lifetime, and consequently slower translational diffusion than layer 2 and bulk water molecules. The experimental studies suggested that the contact angle of water on h-BN can vary from 61.4 to 85.8°, higher than that of g-C3N4, depending on the surface stacking, support material, and exposure to air, which effectively makes h-BN more hydrophobic compared to g-C3N4. The interfacial water molecules have a smaller HB lifetime and a faster diffusion coefficient than g-C3N4. The HB lifetime of water molecules in bulk is less than that in the interface, irrespective of the surface. A slower reorientation lifetime, that is, 2.69 ps, for g-C3N4 interfacial water molecules is observed versus 2.20 ps for h-BN. Our results agree with the experimental observations and can help to understand the hydrophobicity of other relevant materials. © 2023 American Chemical Society.