Browsing by Author "Rajesh Bhardwaj"

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Recent advances in ZnO nanostructure as a gas-sensing element for an acetone sensor: a short review
(John Wiley and Sons Ltd, 2023) Rajneesh Kumar Mishra; Vipin Kumar; Le Gia Trung; Gyu Jin Choi; Jeong Won Ryu; Rajesh Bhardwaj; Pushpendra Kumar; Jay Singh; Seung Hee Lee; Jin Seog Gwag
Air pollution is a severe concern globally as it disturbs the health conditions of living beings and the environment because of the discharge of acetone molecules. Metal oxide semiconductor (MOS) nanomaterials are crucial for developing efficient sensors because of their outstanding chemical and physical properties, empowering the inclusive developments in gas sensor productivity. This review presents the ZnO nanostructure state of the art and notable growth, and their structural, morphological, electronic, optical, and acetone-sensing properties. The key parameters, such as response, gas detection limit, sensitivity, reproducibility, response and recovery time, selectivity, and stability of the acetone sensor, have been discussed. Furthermore, gas-sensing mechanism models based on MOS for acetone sensing are reported and discussed. Finally, future possibilities and challenges for MOS (ZnO)-based gas sensors for acetone detection have also been explored. © 2022 John Wiley & Sons Ltd.
Revolutionizing energy evolution: SnS-Sn2S3 layered structures as exceptional electrocatalytic materials for H2 and O2 generation
(Elsevier Ltd, 2024) Rajneesh Kumar Mishra; Gyu Jin Choi; Ranjana Verma; Sun Hun Jin; Rajesh Bhardwaj; Sandeep Arya; Jay Singh; Jin Seog Gwag
In this paper, we prepared the SnS-Sn2S3 layered structure using the in-situ solvothermal method for hydrogen evolution (HER) and oxygen evolution reaction (OER). XRD and HRTEM confirm the successful synthesis of the orthorhombic crystal structure of the SnS-Sn2S3. Further, SEM images demonstrate the layered shape of the SnS-Sn2S3 nanostructure, promoting the formation of more active sites on the surface for better electrocatalytic activities. Interestingly, during OER investigation, the SnS-Sn2S3 catalyst depicts an overpotential of 359 mV (10 mA cm−2) and a Tafel slope of 90.1 mV dec-1. However, during HER investigation, the SnS-Sn2S3 catalyst describes an overpotential of 162 mV (-10 mA cm−2) and a Tafel slope of 107.6 mV dec-1. Moreover, the SnS-Sn2S3 catalyst unveils superb stability for 2.3 h at 10 mA cm−2 for OER and 4.0 h at −10 mA cm−2 for HER. The OER and HER reaction mechanisms were also discussed to explore the kinetics rate of SnS-Sn2S3 catalyst. © 2024 Elsevier B.V.