Synthesis of 1D and 2D materials,
Synthesis of Nanocomposites,
Flexible Sensors and Actuators
Wearable Electronics Devices
Bodywarmer/Heating Devices
19
Scopus Publications
Scopus Publications
Review on Recent Advances of Nickel Sulfide Nano Electrocatalysts for Hydrogen Evolution Hitha Haridas, Bhargavi Somapur, Harish Sharma Akkera, Nagarjuna Neella, Nagaiah Kambhala Chemistryselect, 2024 Hydrogen is an important energy carrier without carbon emissions. To achieve a carbon‐neutral world, the demand for hydrogen is very significant. In the process of producing green hydrogen, water splitting using electrocatalysts is a desirable process among many methods. The ideal electrocatalyst for hydrogen evolution is the platinum group of metals; however, the limitations of high cost and low abundance hinder large‐scale hydrogen production. Hence, researchers are trying to develop materials from more abundant and less expensive. Hence, in this review, we focus on the fundamental principles of hydrogen evolution reaction (HER) and various synthesis methods and strategies. From the material perspective, we focus on nickel sulfide‐based nanomaterials of different phases during the last four years of development. We compared the electrocatalyst parameters concerning the synthesis methods and strategies chosen. Finally, we have also discussed future challenges. Ultimately, by synthesizing the collective knowledge amassed in the field of HER research, this review endeavors to offer a comprehensive resource for researchers, engineers, and policymakers striving to advance hydrogen‐based energy technologies. In doing so, we aspire to foster continued innovation and collaboration toward realizing a sustainable energy future powered by hydrogen.
Recent advances in anodically fabricated amorphous TiO2 nanotubes crystallization techniques and their applications Raghavendra Garlapally, Niharika MP, B Manmadha Rao, B Venkateswarlu, Nagarjuna Neella, et al. Physica Scripta, 2024 The present summarized study focused on Anodically fabricated TiO2 nanotubes array shows an exceptional physical and chemical properties due to their high surface area as well as thickness near to nano scale regimes. Crystallization of an amorphous TiO2 nanotube plays an important role when it comes to applications point of view. Studies revealed that a change in the annealing process resulted in an enhancement in their structure and properties. In this review, we mainly focus on various annealing techniques, their advantages and drawbacks over the other methods. Additionally, we have reported the effect of morphology and crystal structure of different annealed anodically grown TiO2 nanotubes. Therefore, the anodized TiO2 nanotubes array review will not only have applications in water splitting, hydrogen generation, solar cells but also a suitable potential candidate in the immense applications as micro/nano needles for drug delivery in biomedical as well as different electronic device/sensing approaches in aerospace sectors as well.
Highly sensitive, scalable reduced graphene oxide with palladium nano-composite as strain sensor Suresh Nuthalapati, Vijay Shirhatti, Vaishakh Kedambaimoole, Nagarjuna Neella, M M Nayak, et al. Nanotechnology, 2020 We report a novel strain sensor based on reduced graphene oxide (rGO) with palladium (Pd) nano-composite. The sensor was fabricated on the SS304 stainless-steel substrate using a screen-printing method. Graphene oxide was synthesized using a modified Hummer’s method and reduced using a chemical route. Field emission-scanning electron microscope, x-ray diffraction and Raman spectroscopy were used to characterize the as-synthesized nano-composite. The as-fabricated strain sensor was tested for tensile strain using Micro-universal Test Machine and the change in resistance for different strains was recorded. The sensor response was observed to be stable and linear within the applied strain range of 0–3000 microstrains, and an average gauge factor of 42.69 was obtained in this range.
High-range noise immune supersensitive graphene-electrolyte capacitive strain sensor for biomedical applications Vijay Shirhatti, Vaishakh Kedambaimoole, Suresh Nuthalapati, Nagarjuna Neella, M M Nayak, et al. Nanotechnology, 2019 This paper presents development and performance assessment of an innovative and a highly potent graphene-electrolyte capacitive sensor (GECS) based on the supercapacitor model. Although graphene has been widely researched and adapted in supercapacitors as electrode material, this combination has not been applied in sensor technology. A low base capacitance, generally the impeding factor in capacitive sensors, is addressed by incorporating electric double layer capacitance in GECS, and a million-fold increase in base capacitance is achieved. The high base capacitance (∼22.0 μF) promises to solve many inherent issues pertaining to capacitive sensors. GECS is fabricated by using thermally reduced microwave exfoliated graphene oxide material to form interdigitated electrodes coated with solid-state electrolyte which forms the double layer capacitance. The capacitance response of GECS on subjecting to strain is examined and an enormous operating range (∼300 nF) is seen, which is the salient feature of this sensor. The GECS showed an impressive device sensitivity of 11.24 nF kPa-1 and good immunity towards noise i.e. lead capacitance and stray capacitance. Two regimes of operation are identified based on the procedure of device fabrication. The device can be applied to varied applications and one such biomedical application of breath pattern monitoring is demonstrated.
Supercapacitor Based Approach Towards Development of Graphene Sensors Vijay Shirhatti, Suresh Nuthalapati, Nagarjuna Neella, Vaishakh Kedambaimoolc, M. M. Nayak, et al. NEMS 2018 13th Annual IEEE International Conference on Nano Micro Engineered and Molecular Systems, 2018 Graphene has been extensively studied and used in energy storage applications like Supercapacitors owing to its high Electric Double Layer Capacitance (EDLC). However, this property of Graphene has not been used in Sensor technology. We report a novel approach for the development of Graphene Capacitive sensors by adopting the Supercapacitor property of Graphene. Graphene was synthesized by Electro-exfoliation process followed by Hydrazine hydrate reduction. The obtained material was characterized using XRD and FE-SEM to ensure structural and morphological properties. An Interdigitized Electrode (IDE) pattern was prepared with reduced Exfoliated Graphene (rEG) as electrode and PVA-H2SO4 electrolytic gel was used to realize EDLC. The fabricated strain sensing device was found to have a gauge factor of 97.3. This low cost, flexible, highly sensitive and easy to fabricate device opens up a new area of capacitance based sensors with wide applications in the chemical & automotive industry, healthcare, robotics, aerospace, mining etc.
RGO-PD Nano-Composite Based Films for Strain Measurement Using Screen Printing Technique Suresh Nuthalapati, Vijay Shirhatti, Nagarjuna Neella, Vaishakh Kedambaimoole, Venkateswarlu Gaddam, et al. NEMS 2018 13th Annual IEEE International Conference on Nano Micro Engineered and Molecular Systems, 2018 In this paper we are reporting, a strain sensor fabricated by screen printing method using a novel Reduced Graphene Oxide (RGO) and Palladium (Pd) nano-composite on a stainless steel substrate. Pd was chosen due to its higher strain sensitivity compared to other metal composites and screen printing method was adopted because of low cost and easy fabrication. A specified amount of Pd filler was mixed with RGO to enhance its functional and mechanical properties under strain application. As-synthesized nano-composite was characterized by Field Emission-Scanning Electron Microscope (FE-SEM) and X-ray diffraction (XRD) for its surface morphology and crystallinity of the composite. The change in electrical resistance of as-fabricated strain sensor was observed when a mechanical strain was applied on it and its strain sensitivity (Gauge factor) was estimated by cantilever bending method. The Gauge factor as high as 15 was observed for as-prepared strain sensor. The presently developed high sensitive strain gauges are useful to measure force, stress/strain, pressure and displacements in the fields of aerospace, civil engineering, automobile and transport.
Screen Printed rGO-Pd Nana-Composite films on a Flexible Substrate as Temperature Sensor Suresh Nuthalapati, Vaishakh Kedambaimoole, Vijay Shirhatti, Nagarjuna Neella, Venkateswarlu Gaddam, et al. 2018 3rd International Conference for Convergence in Technology I2ct 2018, 2018 We report, a screen printed nano-composite films made with reduced Graphene Oxide (rGO) and Palladium (Pd) for temperature sensor application. The rGO was synthesized using modified Hummer's method and Pd was mixed with as-synthesized rGO to avoid the agglomeration formed by rGO nano sheets. An array of rGO-Pd nano-composite films were fabricated on flexible kapton substrate using screen printing technique, which is of low cost and simple process. As-synthesized rGO and rGO-Pd nano-composite's surface morphology and crystallinity were studied using Field Emission-Scanning Electron Microscope (FE-SEM) and X-ray diffraction (XRD). As-prepared nanocomposite films were tested using cold and hot chamber to verify it's response with respect to change in temperature. It was observed that the film responds linearly with negative temperature coefficient (NTC). The sensitivity and temperature coefficient of resistance (TCR) of the as-fabricated nanocomposite films were observed to be $\\pmb{0.7028}\\ \\boldsymbol{\\Omega}/\\mathbf{K}$ and. $\\pmb{-2.0312}\\ \\mathbf{x}\\ \\pmb{10^{-3}} \\boldsymbol{\\Omega/\\Omega}/\\mathbf{K}$ respectively. These flexible temperature sensors can be used in the field of biomedical, food processing, aerospace, communication and automobile for monitoring of temperature.
Waste to wealth concept: Disposable RGO filter paper for flexible temperature sensor applications Nagarjuna Neella, Vaishakh Kedambaimoole, Venkateswarlu Gaddam, M. M. Nayak, K. Rajanna Aip Conference Proceedings, 2018 We have developed a flexible reduced graphene oxide (RGO) temperature sensor on filter paper based cellulose substrate using vacuum filtration method. One of the most commonly used synthesized methods for RGO thin films is vacuum filtration process. It has several advantages such as simple operation and good controllability. The structural analysis was carried out by FE-SEM, in which the surface morphology images confirm the formation of RGO nanostructures on the filter paper substrate. It was observed that the pores of the filter paper were completely filled with the RGO material during the filtration process, subsequently the formation of continuous RGO thin films. As a results, the RGO films exhibits a piezoresistive property. The resulted RGO based films on the filter paper reveals the semiconducting behavior having sensitivity of 0.278 Omega/degrees C and negative temperature coefficient (NTC) about -0.00254 Omega / Omega /degrees C. Thus, we demonstrate a simplified way for the fabrication of RGO films on filter paper that possesses better and easier measurable macroscopic electrical properties. Our approach is for easy way of electronics, cost-effective and environment friendly fabrication route for flexible conducting graphene films on filter paper. This will enable for the potential applications in flexible electronics in various fields including biomedical, automobile and aerospace engineering.
Acoustic transducer based on ZnO nanorods Venkateswarlu Gaddam, Nagarjuna Neella, K. Rajanna, Veera Pandi N, M.M. Nayak 2017 IEEE 12th International Conference on Nano Micro Engineered and Molecular Systems NEMS 2017, 2017
