A research paper titled “First Principle Identification of 2D-MoS2 based Composite Electrodes for Efficient Supercapacitor Application” is published by Samadhan Kapse, PhD student, as First Author and Bennet Benny, BSc Physics Student, (Same Contributed First Author) in the Journal of energy storage, Elsevier having an Impact Factor of 6.583. The paper publication has been guided and supervised by Dr Pranab Mandal (Co-Author) and Prof Ranjit Thapa (Corresponding Author) from the Department of Physics, SRM University-AP.
1T Molybdenum disulfide (1T-MoS2) has been widely studied experimentally as an electrode for supercapacitors due to its excellent electrical and electrochemical properties. Whereas the capacitance value in MoS2 is limited due to the lower density of electrons near the Fermi level, and unable to fulfil the demand of industry i.e. quantum capacitance preferably higher than 300 μF/cm2. Here, we investigated the performance of 2H, 1T, and 1T’ phases of MoS2 in its pristine form and heterostructures with carbon-based structures as an electrode in the supercapacitors using density functional theory. Specifically, we reported that the underneath carbon nanotube (CNT) is responsible for the structural phase transition from 1T to 1T’ phase of MoS2 monolayer in 1T’-MoS2/CNT heterostructure. This is the main reason for a large density of states near the Fermi level of 1T’-MoS2/CNT that exhibits high quantum capacitance (CQ) of 500 μF/cm2 at a potential of 0.6 V. Also, we observed that the nitrogen doping and defects in the underneath carbon surface amplify the CQ of heterostructure for a wider range of electrode potential. Therefore, the 1T’-MoS2 /N doped CNT can be explored as an electrode for next-generation supercapacitors.
Today’s increasing demand for energy storage technologies is highly dependent on batteries, fuel cells, supercapacitors, etc. The supercapacitors are greatly efficient due to advantages such as high power density, wide operating temperature range, large charge-discharge cycles. The recent focus of researchers is to find promising electrode materials for supercapacitor application. Among all reported works, the MoS2 nanosheet is found to be a prime candidate for supercapacitors with a high power density as well as energy density. Therefore, it is important to understand the origin of capacitance in MoS2 and their composites to design promising electrodes for supercapacitors. Also, the identification of ideal MoS2 based composites for efficient supercapacitor application is a grand challenge using only experimental approaches.
Using density functional theory, we can identify the promising electrode materials for supercapacitor application based on various graphene, 2D metal chalcogenides and their heterostructures. The quantum capacitance (CQ) is the cost-effective method to estimate the performance of any low density of states materials such as graphene, MoS2, etc towards supercapacitors.Continue reading →
Swikriti Khadke, Pragya Gupta, and Shanmukh Rachakunta from third-year Computer Science Engineering have published a research paper titled “Efficient Plastic Recycling and Remold Circular Economy using the Technology of Trust – Blockchain” along with their mentors from SRM University-AP Dr Jatindra Kumar Dash, Dr Goutam Kumar Dalapati and Dr Sabyasachi Chakrabortty in the peer-reviewed journal Sustainability.
Global plastic waste is increasing rapidly. The strategic management of plastic waste and recycling can preserve environmental species and associated costs. The utilization of plastic can be done by introducing Blockchain during plastic waste recycling. Automation for the segregation and collection of plastic waste can effectively establish a globally recognizable tool using Blockchain-based applications. Collection and sorting of plastic recycling are feasible by keeping track of plastic with unique codes or digital badges throughout the supply chain. Efficient recycling technology is essential to reduce plastic pollution. Many technologies have been employed to enhance plastic recycling. Among them, blockchain is promising for plastic recycling and circular economy (CE). Blockchain, a distributed ledger, consists of some ordered blocks which are unchangeable. This can be considered an exemplary way to push the transactions of their customers under the same blockchain technology. The research group used machine learning techniques to predict plastic generation globally so that they could see the impact it will make in the coming future. The students have used ARIMA – Auto-Regressive Integrated Moving Average for the study.
The potential idea is to utilize an approach wherein recyclers can keep track of generated waste as it moves through the various chains. A platform that works by tracking recycling activities across a local recycling supply chain on the Blockchain. When this will be publicly available, consumers can also use the ledger info to make more informed purchasing decisions. The Blockchain can be utilized to track individual items through the recycling supply chain by creating physical markers like QR codes.
The suggested Blockchain-based platform can be implemented in various nations with an autonomous waste collector and storage system. This process can be expanded to individual collectors and storage systems. The novel process will be created by incorporating a reward-based Blockchain scheme with the collaboration of global businesses and local waste collectors. The proposed model further allows the effective sharing of databases among various supply chains to create a CE.
Talking about the social implications of the research, the students firmly believe that the study will result in the introduction of new technology in the recycling industry and promote awareness about technology in rural areas. Developing a platform and implementing blockchain and other facilities will be the focus of these young innovative brains of SRM University-AP in the forthcoming days.
Read the full paper here: https://doi.org/10.3390/su13169142Continue reading →
An interactive session between Prof U Ramamurty, President Chair Professor, School of Mechanical & Aerospace Engineering at Nanyang Technological University (NTU), Singapore, and the faculty members of SRM University – AP, Andhra-Pradesh was held on Monday.
During the discussion, Prof Ramamurty emphasized the importance of research collaboration between faculty members from different research areas and about utilizing expertise to achieve significant scientific output.
Dr Pardhasaradhi Maram from the Department of Chemistry, Dr Sabyasachi Mukhopadhyay from the Department of Physics, and Prof G S Vinod Kumar from the Department of Mechanical Engineering presented their detailed research areas that focus on storage devices, catalysts for value-added products, energy and sensing devices, novel metallic materials, additive manufacturing of metals and Bio-implants, and industry collaborative research work.
Prof Ramamurty said that he is glad to see that productive science is being done at SRM University-AP. “Given that the University has started only 4 years ago and been functioning amidst a pandemic for more than one and a half years, the progress in research is significant and very impressive. Interdisciplinary efforts between various departments in the University will give effective results”, he added.
Prof D Narayana Rao, Pro-Vice-Chancellor, SRM University – AP expressed his interest in establishing NTU – SRM joint Centre for Advanced Research in functional and structural materials at SRM University campus to Prof Ramamurty. The centre that Prof Rao envisions will provide an opportunity to synergize the expertise and resources of NTU, Singapore, and SRM University – AP to carry out front-line research in the areas of novel materials, self-healing materials and also additive manufacturing (3D Printing of metals and bio-implants).Continue reading →
A research paper titled “Nitrogen doping derived bridging of Graphene and Carbon Nanotube composite for oxygen electroreduction” has been published by Prof Ranjit Thapa, Professor of Physics, SRM University – AP, as a co-author, in International Journal of Energy Research, having Impact Factor of 5.164.
In this work, the research group investigated the origin of high catalytic activity of oxidic-N configuration in nitrogen-doped CNT and graphene heterostructure using density functional theory (DFT). We have plotted the free energy profile of the oxygen reduction reaction (ORR) to estimate the thermodynamic overpotential and catalytic performance of the respective active sites. The overpotential is related to the quantifying parameter ∆GOH (with R2 = 0.98) and the π electron density at the Fermi level, defined as an electronic descriptor, which is highly correlated with the ∆GOH with R2 value 0.96. For various N doped configurations, we correlated the ∆GOH values with π electron density at the Fermi level and found that the carbon site adjacent to the oxide-N configuration is a more prominent site for ORR. Further, we show that the oxidic-N configuration in the heterostructure of graphene and CNT is the ideal configuration, which gives a lower overpotential of 0.54 eV for ORR on adjacent carbon sites. Therefore, the charge transfer occurs from underneath CNT to graphene and increases the value of π electron density at the Fermi level which leads to the higher catalytic performance of the active site.
In the early 20th century, fuel cells were invented and their global impact has not reached up to its regular commercialization when compared with battery technology. The fuel cell device could be a powerful technique to generate electricity for large energy demand without greenhouse gas emissions. However, other major hurdles in the commercialization of fuel cell devices are the cost of platinum (as a catalyst), its poisoning and stability. Recently, carbon-based materials such as graphene, carbon nanotubes and activated carbon have been evolved as metal-free low-cost catalysts due to their (i) high abundance/yield (ii) reactivity towards oxygen just by introducing impurities like heteroatoms or other metals. However, identifying an efficient design principle to search optimal doping configurations in various carbon systems is a grand challenge for researchers.
This work is done in collaboration with Research Institute, SRM Institute of Science & Technology, Kattankulathur-603203, Chennai (India).
In future, the study aims to propose the effective design principle for various doped carbon systems as a catalyst to identify the optimal active sites and configurations for ORR. The role of π orbital in carbon systems such as graphene, graphene nanoribbons, carbon nanotube, etc is very important and can be a general electronic descriptor to define catalytic activity. Also, π electron descriptors and machine learning algorithms based combined approach can boost the search for ideal carbon catalyst for ORR with low DFT cost.
Read the full paper here: https://doi.org/10.1002/er.7179Continue reading →
Ever since the breakthrough research on H2 photogeneration from water using TiO2 under UV-light irradiation, an enormous amount of research has been conducted on photochemical H2 evolution using different semiconductor-based photocatalysts. Consequently, a research paper titled “Controlled Loading of MoS2 on Hierarchical Porous TiO2 for Enhanced Photocatalytic Hydrogen Evolution” has been published by Prof Ranjit Thapa, Professor of Physics, SRM University – AP, as a co-author, in The Journal of Physical Chemistry C, having an Impact Factor of 4.189.
In this work, Prof Thapa describes three important factors for helping in the generation of hydrogen using proposed MoS2/TiO2 catalyst, (i) TiO2 for effective charge transfer, (ii) MoS2 for plasmon induction (iii) large surface area and active sites. It was shown that hierarchical porous TiO2 can be interfaced successfully with marigold-flower-like MoS2 flakes with intriguing photophysical properties, viz., visible-light response, controlled electron−hole recombination, and sustainable H2 production over prolonged light irradiation due to the synergic effect of flowerlike MoS2 and the fibrous wormhole mesoporous channel of TiO2. Further, the researchers have used density functional theory (DFT) to identify the active sites and calculated the change in Gibbs free energy (ΔGH). “We have also studied the charge density difference to understand about electron transfer pathway. The change free energy of hydrogen adsorption (ΔGH*) is a good indicator to estimate the hydrogen evolution activity in the acidic medium. From the DFT study, it is clear that O sites of MPT heterostructure are more favourable for HER reactivity”, said Prof Ranjit Thappa.
Social implications of the research:
In the last few decades, with the decline in non-renewable resources and increasing environmental pollution, significant attention has been given to renewable and clean energy domains. Hydrogen is considered one of the most suitable energy carriers due to its higher energy density per unit mass in comparison to other chemical fuels. In recent times, photocatalytic fission (Photocatalysis is a process in which light energy is used to drive pairs of chemical reactions. Through the absorption of light, an excited electron/hole pair is produced) of water has been considered an attractive solution for solar to chemical H2 energy conversion. Also, the process of water splitting is highly endothermic. Therefore, the development of an excellent, stable, efficient, and economical photocatalyst for ultrahigh H2 production efficiency is paramount to researchers.
This work is done in collaboration with the Department of Energy and Environmental Engineering, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India.
Prof Ranjit Thapa is doing an investigation to find the possibility of hydrogen evolution reaction (HER) on multiple borophene analogues (α, β12, χ3) on all unique sites. Understanding the role of the coordination number of the boron atoms in the borophene analogues with the HER efficiency, and studying the pathways Volmer-Tafel (V-T) on each site to understand the completed HER process on borophene analogues are his future research projects. His research group is also interested to identify the role of sigma and pi-electron occupancy on the V-T pathway.
Read the full paper here: https://doi.org/10.1021/acs.jpcc.1c01922Continue reading →