Research Work at a Glance

Electrocatalytic water/seawater splitting research (nanostructured catalysts)

Green Hydrogen (H₂) production, with its high calorific value and potential for net-zero carbon emissions in fuel cell engines, is a highly sought-after area of research and commercial development worldwide. Electrocatalytic water splitting in an electrolyzer stands out as one of the most promising approaches for H₂ production. Advanced research has revealed various mechanisms for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on electrocatalyst surfaces to enhance water splitting efficiency. Literature suggests that moderate adsorption free energy (ΔG(H*) ≈ 0) and high surface coverage by H* (the active species or adsorbed hydrogen) are key for HER. Similarly, for effective OER, moderate adsorption/desorption free energy, high surface coverage by *O, *OH, and *OOH active species, and the lowest energy barriers are essential. By optimizing electrocatalysts based on these factors, it is possible to enhance the efficiency of multiple electron-coupled transfer half-cell reactions and the overall electrocatalytic water splitting process (ΔGo = +237.2 kJ/mol, ΔE = 1.23 V). This optimization can reduce overpotentials, while improving stability, mass activity, and exchange current density. 

Keeping these points in mind, our group developed a few novel and interesting nanostructured electrocatalysts suitable for efficient alkaline seawater/natural water splitting reaction to produce green hydrogen. By Sasanka Deka

Electrocatalytic water splitting: We developed trimetallic FeCoPd polyhedral alloy nanoparticles (NPs) as a new highly efficient and promising bifunctional electrocatalyst for hydrogen and oxygen evolution reactions (HER and OER). We also demonstrated the development of an entirely new Cu−Co−B  amorphous alloy nanosheet (NS), which can act as an industrially promising electrocatalyst for the OER. Spiky ball-shaped monodispersed TMP nanoparticles composed of Fe, Co, and Ni are developed and used as efficient electrocatalysts for hydrogen and oxygen evolution reaction (HER, OER), and overall water splitting in alkaline medium; and their surface chemistry was explored to understand the reaction mechanism. e.g. nanostructured Mo-doped Ni2P, CuCo2S4, Co3S4, NiCo2O4, PdSn, PdCoFe, FeCoNiP, FeCoP, CeO2, FeNiB, etc.

Photocatalysis: Photocatalytic green hydrogen generation: 

Photocatalytic water splitting is a process that uses light, typically sunlight, to drive the dissociation of water molecules (H₂O) into hydrogen (H₂) and oxygen (O₂) through the action of a photocatalyst. Typically, photocatalytic H2 production from water is a low efficiency process using both UV-light-responsive and visible-light-responsive photocatalysts, which is primarily due to high recombination rates of photoinduced electrons and holes. In order to achieve higher H2 production efficiencies from water splitting, we aimed to develop a few novel and advanced photocatalysts. These includes single atom catalysts (SAC), metal chalcogenides and metal oxide semiconductor nanoparticles.  e.g. CuCo2S4, g-C3N4, Pt/Pd/Ni-SAC, CuIn2S4, etc.

Supercapacitors: Energy storage:

Electrochemical supercapacitors (SCs) are a highly efficient and promising type of rechargeable energy storage system (EES) that has garnered significant attention in recent years. This is due to their rapid charging and discharging capabilities (thanks to fast redox reaction kinetics), along with high capacity, power and energy densities, and long cycle life. Compared to commercial batteries, SCs are emerging as one of the most promising EES technologies, as both electrical and chemical energy are carried by the same carrier, the electron. SCs have proven to be highly reliable in applications such as lightweight portable electronic devices and hybrid power vehicles.  With the rapid advancement in the field of nanoscience and nanotechnology, the electrochemical performances of supercapacitors have been significantly improved. This is attributed to the electrode’s high surface area for storing charges and the ease with which the electrolyte diffuses into the nanostructured electrodes. However, the current obstruction in the performance of SCs is their low energy density and it still remains a bottleneck. As a contribution to this field, we have developed a few highly efficient functional nanostructured materials/electrodes to store energy electrochemically. These include nanostructured NiCo2O4, SnS2, g-C3N4, CuCoB, NiCoCuB, SnCoSe, ZnCoNi-LDH, CuCo-LDH, etc.

Flexible Solid-State Symmetric/Asymmetric Supercapacitors (device)

With the evolution of supercapacitors, flexible and wearable electronic devices acting as promising soft power sources have gained tremendous attention. Such a device with extreme bending, twisting, and foldable features and extraordinary riveting properties like high capacitance, long cycling stability and small size perhaps will be one of the best suitable patch devices in the near future. We made several flexible supercapacitor devices in the lab, which show a highly stable electrochemical performance even under extreme mechanical deformations and no leakage or evaporation of the electrolyte on bending the cell at different angles. These are made with the materials developed as mentioned above.

1. “Morphology oriented nanostructured ternary metal chalcogenide semiconductors and their use of” funded by CSIR (Council of Scientific and Industrial Research), New Delhi, 2023-2026.

2. “Development of single atom catalysts (SAC) for superior and robust photocatalytic applications” funded by SERB-DST (Science and Engineering Research Board), 2022-2025.

3. “Development of nanostructured mixed metal oxide and metal chalcogenide materials based effective electrodes and their use in supercapacitor devices” funded by TMD-DST (Department of Science and Technology, India), 2019-2022.

4. “Development of advanced nanomaterials for benchmark electrocatalytic hydrogen and oxygen evolution from water” funded by SERB-DST (Science and Engineering Research Board), 2017-2020.

5. “Synthesis, characterization and advanced multifunctional applications of novel chalcogenide semiconductor nanocrystals” funded by CSIR (Council of Scientific and Industrial Research), New Delhi, 2014-2018.

6. “Synthesis, characterization and evaluation of anticancer activity of novel bioessential transition metal complexes having tumor targeting and antitumor active ligands” funded by DBT (Department of Biotechnology), 2014-2018.

7. “Synthesis, characterization, porous assembly and application of novel metal-metal oxide hybrid nanocrystals” funded by SERB-DST, 2012-2025.

8. “Studies on the optical and magnetic properties of semiconductor-magnetic oxide hybrid nanocrystals” funded by BRNS-BARC-DAE (department of Atomic Energy), 2012-2015.

9. “Synthesis and studies of the optical, plasmonic and magnetic behavior of Ni/Ag-semiconductor hybrid nanostructures” funded by DST-DAAD (German Academic Exchange Service, Indo German), 2014-2016.

10. “Complex nanostructures and their applications in optics, photonics and electronics” funded by DST Purse grant, 2011, 2015, 2016.

11. University of Delhi Institute of Excellence (IoE) minor project 2021, 2022, 2023 and 2024.

12. University of Delhi funding through Faculty rechrage program/SEED money 2010 to 2024.