Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
3 results
Search Results
Item Growth of octahedral structured AgBiS2 single crystals and its insights on the high performance electrocatalytic hydrogen generation(Elsevier Ltd, 2024) Jauhar, R.O.M.; Ramachandran, K.; Deepapriya, S.; Joshi, S.; Ghfar, A.A.; Rao, L.; Badekai Ramachandra, B.R.; Udayashankar, N.K.; Vadivel, V.; Raji, R.; Kim, B.C.; Rodney, J.D.Given the enormous depletion of fossil fuels and growing environmental concerns, there is an immediate need to develop alternative and clean energy sources. Hydrogen (H2), recognized for its cleanliness and renewability, is poised to meet future energy requirements. Consequently, ongoing research is focused on the development of electro-active, durable, and cost-effective catalysts to replace expensive noble metal-based electrocatalysts. In this study, microscale AgBiS2 chalcogenide derived from a single crystal is reported as promising electrocatalysts for the Hydrogen Evolution Reaction (HER) with a remarkably low overpotential. The physico-chemical characterization of the AgBiS2 catalyst has been investigated using various analytical techniques. The synthesized AgBiS2 catalyst exhibits excellent HER activity, manifesting a low overpotential of 86 mV at a current density of 10 mA cm−2 and a Tafel slope of 44 mV dec−1, along with superior stability even after 24 h in HER at a very high current density. The developed AgBiS2 also showcased stable production when subjected to a two-electrode system. The enhanced alkaline HER activity of AgBiS2 can be attributed to its phase purity, high crystallinity, and the presence of high active sites. The observed high electrochemical performance and stability position AgBiS2 as a potential electrocatalyst for the hydrogen evolution reaction. This finding holds significant promise in the quest for efficient, durable, and economically viable catalysts to drive the shift towards clean and renewable energy sources. © 2024 Hydrogen Energy Publications LLCItem Sustained hydrogen production through alkaline water electrolysis using Bridgman–Stockbarger derived indium-impregnated copper chromium selenospinel(Elsevier Ltd, 2024) Jauhar, R.M.; Raji, R.; Deepapriya, S.; Raja, A.; Rao, L.; Joshi, S.; Era, P.; Badekai Ramachandra, B.R.; Udayashankar, N.K.; Vadivel, V.; Mangalaraja, R.V.; J, J.; Ghfar, A.A.; Senthilpandian, M.; Kim, B.C.; Rodney, J.D.The depletion of conventional fossil fuels necessitates the development of sustainable energy alternatives, with electrochemical water splitting for hydrogen (H2) production being a promising solution. However, large-scale hydrogen generation is hindered by the scarcity of cost-effective electrocatalysts to replace noble metals such as Pt and RuO2 in the Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER). In this study, we report the synthesis of CuCr2-xInxSe4 (x = 0, 0.2, 0.4) using a dual approach combining the Bridgman-Stockbarger method and ball milling. Among the synthesized materials, CuCr1.8In0.2Se4 demonstrates outstanding HER activity in 1.0 M KOH, achieving a potential of ?0.16 V vs. RHE at a current density of 10 mA cm?2. Moreover, the material shows remarkable durability during a three-electrode accelerated degradation test in an alkaline medium, maintaining its performance over 24 h at a constant current density of ?200 mA cm?2, with a stable potential of ?0.57 V vs. RHE. Additionally, CuCr1.8In0.2Se4 was tested in a two-electrode configuration alongside CoFe LDH, achieving a benchmark of 1.7 V for overall water splitting. It sustained a current density of 400 mA cm?2 for 24 h in an accelerated degradation test, exhibiting a minimal loss of 0.1 V after the testing period. These results highlight CuCr1.8In0.2Se4 as a promising non-noble metal catalyst for HER, demonstrating its potential to reduce reliance on noble materials for large-scale hydrogen production. © 2024 Hydrogen Energy Publications LLCItem Recycling waste plastics and biowaste into high-performance NiCo-MOF/activated carbon electrocatalyst for overall water splitting(Elsevier Ltd, 2025) Nayak, M.P.; Rao, L.; Rodney, J.D.; S, S.; Rohit, A.G.; Badekai Ramachandra, B.R.Environmental and energy crises are the most significant global challenges. Developing non-precious and environmentally sustainable electrocatalysts remains critical for advancing renewable hydrogen production. This study presents a novel hybrid electrocatalyst comprising a NiCo-BDC Metal-Organic Framework (NiCo-MOF), where the BDC (Benzene 1,4-di carboxylic acid) ligand was obtained by recycling waste poly(ethylene terephthalate) (PET) bottles, integrated with activated carbon (AC) derived from dried drumstick (Moringa olifera) biowaste, via a one-pot hydrothermal method. The research emphasizes optimizing the AC content within the MOF matrix to enhance catalytic performance. The synergistic interaction between NiCo-MOF and AC significantly reduces the overpotentials required for the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) in an alkaline medium. Notably, the optimized composite, NiCo-MOF@40AC, exhibited enhanced crystallinity, BET surface area, and electrocatalytic activity. At a current density of 100 mA cm?2, NiCo-MOF@40AC achieved overpotentials as low as 217 mV for HER with a Tafel slope of 105.6 mV dec?1 and 315 mV for OER with a Tafel slope of 42.2 mV dec?1. Furthermore, this material demonstrated robust stability over a 24 h chrono potentiometric test, maintaining performance at an elevated current density of 200 mA cm?2. In a two-electrode system, NiCo-MOF@40AC needed only 1.58 V to sustain a current density of 10 mA cm?2, exhibiting stability over 48 h and 24 h at a current density of 10 mA cm?2 and 400 mA cm?2, respectively. An average faradaic efficiency was found to be 93.48 % for HER and 91.91 % for OER. These findings highlight the potential of NiCo-MOF@40AC as an efficient electrocatalyst, characterized by a high surface area, rapid electron transfer, favorable structural properties, and enhanced reaction kinetics. © 2025 Hydrogen Energy Publications LLC