Browsing by Author "Pandey, Jay"

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Design and synthesis of highly stable poly(tetrafluoroethylene)-zirconium phosphate (PTFE-ZrP) ion-exchange membrane for vanadium redox flow battery (VRFB)
(Springer, 2017-01) Pandey, Jay
Vanadium redox flow battery (VRFB) is a promising technology for large-scale renewable energy storage. Design of ion-exchange membrane (IEM) with desired properties like low-cost, mechanically chemically stable, low vanadium ion permeability and high proton conductivity is one of the major challenges. Here, we report the design and synthesis of novel poly(tetrafluoroethylene)-zirconium phosphate (PTFE-ZrP) asymmetric IEM using a simple brush coating method. XRD results confirmed the presence of α-ZrP crystalline phase onto the top layer of the membrane. Excellent mechanical strength was observed with burst pressure of 3.22 × 105 N m−2. Oxidative stability of membrane in Fenton’s reagent was much better than Nafion-115. Vanadium ion (V4+) permeability of the membrane was more than three times lower than that of Nafion-115. Single-cell VRFB with PTFE-ZrP membrane showed ∼80% energy efficiency below 30 mA cm−2. Very high columbic efficiency ∼100% of VRFB with PTFE-ZrP membrane confirmed little contamination of electrolyte due to cross-mixing.
Developing a Thermal- and Coking-Resistant Cobalt–Tungsten Bimetallic Anode Catalyst for Solid Oxide Fuel Cells
(ACS, 2016-06) Pandey, Jay
We report the development of a novel Co–W bimetallic anode catalyst for solid oxide fuel cells (SOFCs) via a facile infiltration-annealing process. Using various microscopic and spectroscopic measurements, we find that the formed intermetallic nanoparticles are highly thermally stable up to 900 °C and show good coking resistance in methane. In particular, a fuel cell fitted with Co3W anode shows comparable activity (relative to Co) in the electro-oxidation of hydrogen and methane at 900 °C without suffering significant degradation during a longevity test.
Developing hierarchically porous MnOx/NC hybrid nanorods for oxygen reduction and evolution catalysis
(RSC, 2017) Pandey, Jay
Electrochemical oxygen reduction and evolution reactions (ORR and OER) play a vital role in the field of energy conversion and storage. The problem is that both processes are sluggish, requiring precious-metal catalysts. Here, starting from abundant precursors and using a simple synthesis approach, we report the preparation of a good bifunctional oxygen electro-catalyst: a composite nanorod of manganese oxides and nitrogen-doped carbon. This material has hierarchical porosity, facilitating the mass transfer within the electrode. The nitrogen-doped carbon forms contiguous 3D network, connecting the isolated MnOx nanoparticles and ensuring superior electrical conductivity. Importantly, the MnOx particles contain manganese of mixed oxidation states; aligned with the nitrogen-doped carbon, this hybrid is among the best non-noble-metal ORR/OER catalysts in alkaline media, outperforming even Pt and RuO2 catalysts.
Development of machine learning based model for low-temperature PEM fuel cells
(Elsevier, 2024-09) Pandey, Jay
Low-Temperature Proton Exchange Membrane Fuel Cells (LT-PEMFC) are favored as an alternative power source due to their high efficiency, rapid initialization, shut-down cycles, and zero emissions. Developing an effective model for LT-PEMFC is essential. In this study, machine learning models are created for LT-PEMFC, utilizing techniques such as Gradient Boosting Regression (GBR), Random Forest (RF), eXtreme Gradient Boosting (XGBoost), and Light Gradient Boosting Machine (LightGBM) to predict cell voltage based on operating parameters. The dataset is generated using an in-house physics-based MATLAB model, complemented by experimental data from elsewhere. GBR exhibits superiority over XGBoost, LightGBM, and RF. These data-based models for LT-PEMFC, developed on generated datasets, achieve R 0.99 and MAPE 0.06 during testing. These models are further validated on experimental data with R 0.90 and MAPE 0.1. This underscores the ability to construct accurate data-based models and thus reducing reliance on extensive experimentation.
Effect of Operating Variables on DMFC Performance for the Synthesized Si-PWA/PVA Nanocomposite Membrane
(Life Science Global, 2015) Pandey, Jay
Electrochemical Performance of DMFC was studied under the effect of various operating parameters like temperature, methanol concentration and relative humidity (RH) for the synthesized silica immobilized phosphotungstic acid-poly(vinyl alcohol) (Si-PWA/PVA) nanocomposite membrane (thickness 80-100 µm). The optimized 1.5 Si-PWA/PVA membrane showed good electrochemical properties (transport number: 0.92 and IEC: 0.90 meq/g) with excellent mechanical strength, thermal and chemical stability. Open circuit voltage (OCV) decay was significantly lower in comparison to Nafion-117. Maximum power density (45.7 mWcm-2) was obtained at 60oC cell temperature. DMFC performance exhibited better performance even at higher methanol concentration (2 M) demonstrating lower concentration over potential. The appreciable rise in the peak power density observed at higher relative humidity (90%) showed good water stability of the membrane. Performance of the DMFC with the synthesized composite membrane was comparable to the state of the art Nafion-117.
Electrocatalyst for the oxygen reduction reaction (ORR): towards an active and stable electrocatalyst for low-temperature PEM fuel cell
(Springer, 2024-08) Pandey, Jay
Green hydrogen–fueled low-temperature proton exchange membrane (PEM) fuel cells have emerged as one of the most attractive technologies for electric-vehicle (EV) applications due to their high efficiency, zero emissions, and potential for renewable energy integration. The performance of the PEM fuel cells is significantly affected by the electrochemical activity of the oxygen reduction reaction (ORR) catalyst. This review comprehensively examines the role of ORR electrocatalysts in PEM fuel cell efficiency for portable, transport, and stationary applications. In this direction, we discuss the fundamentals of PEM fuel cell operation, the critical role of electrocatalysts, and advanced characterization techniques. A detailed overview of ORR electrocatalyst types, including platinum-based, non-noble metal-based, and carbon-supported as well as noncarbon supported, is presented, emphasizing recent advancements in design and synthesis. The review concludes with discussing current challenges and future directions for ORR electrocatalyst development. Understanding the characteristics and recent developments of ORR catalysts is essential for researchers and engineers to optimize the performance and durability of PEM fuel cells, thereby promoting the wider adoption of clean and efficient energy technologies. By providing insights into electrocatalyst characteristics and emerging trends, this work aims to accelerate the adoption of clean and efficient PEM fuel cell technology.
Electrochemical activity of tungsten oxide doped carbon (WO3/C) catalyst for hydroquinone/benzoquinone redox flow battery
(Elsevier, 2023-07) Pandey, Jay
The research in organic flow batteries is emerging as the cost of the vanadium electrolyte limits the grid-scale application. Tungsten trioxide doped carbon (WO3/C) electrocatalyst is developed to examine its potential in hydroquinone - benzoquinone redox flow battery (HQ/BQ RFB). The catalyst is characterized by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR) and confirms the formation of active WO3/C electrocatalyst. The electrochemical activity of the synthesized WO3/C electrocatalyst is inspected by cyclic voltammetry (CV). It shows comparatively high anodic and cathodic peak currents, low charge transfer resistance, and relatively high electrokinetic reversibility. The charge–discharge test on single cell HQ/BQ RFB is conducted using pristine carbon paper (CP), and WO3/C coated carbon paper (WO3/C-CP). The columbic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of the RFB using WO3/C-CP are around 90%, 75%, and 70%, respectively, which are significantly higher than the CP. The improvement in results demonstrates that the WO3/C electrocatalyst is better at providing active sites and improving the electrochemical reactions kinetics, thus suits the application of HQ/BQ RFB.
Enhanced photocatalytic removal of Cd(II) from aqueous solution using Bi/S co-doped carbon quantum dots
(Elsevier, 2024) Pandey, Jay
In this study, S and Bi Co-doped carbon quantum dots were synthesized and their application for Cd(II) removal was investigated. All the experiments were performed in batch mode and effect Bi/S ratio on pH was investigated. It was observed that 12 pH is most suitable for fast removal of Cd2+. The optimized Bi/S ratio was further investigated for effect of adsorbent dosage, initial concentration of Cd(II). Addition of four scavenger solvent namely formaldehyde, acetic acid, ethanediamine and methanol was investigated for enhancement in the photocatalytic activity. Maximum removal efficiency was observed with ethandiamine ∼94% at 300 ppm as compared to formaldehyde (∼90.3%), methanol (∼86.7%) and acetic acid(∼86.3%) indicating that amine group is more suitable as scavenger molecule. Adsorption isotherms of Cd(II) on Bi/S doped on CQD were fitted for different adsorption isotherm model namely Langmuir, Freundlich and Temkin isotherms. Both Lanmguir and Temkin isotherm were observed to fit well with R2 value above 98% as compared to Freundlich with lower R2 value (∼95.3%), indicating that a combination of chemisorption phenomenon as well as availability of energy of electron could be responsible for the Cd(II) removal. Thermodynamic parameters both enthalpy change and entropy change were estimated as −10.76 kJ/mol and −11.2 kJ/mol K. All three parameters were negative indicating that the process was spontaneous and exothermic.
Graphite Supported Silica Immobilized Phosphotungstic Acid Based Ion-Conducting Inorganic Membrane
(ASME, 2018-06) Pandey, Jay
An asymmetric, inorganic ion-conducting membrane was synthesized by depositing a top layer containing silica-immobilized phosphotungstic acid (Si-PWA) over a graphite sheet. Surface morphology, thermal stability, and structure of the top layer of the membrane were studied using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR), respectively. The transport number and specific conductivity of the membrane were measured using membrane potential and impedance measurements, respectively. The composition of the top layer was varied by changing the molar ratio of PWA and tetraethoxy orthosilicate (TEOS) in the casting sol. The transport number and specific conductivity of the membrane increased on increasing PWA fraction in the casting solution. The highest transport number for sodium ion was 0.98 for PWA: TEOS molar ratio of 1.5. Specific conductivity of the membrane, with 0.5 PWA: TEOS, was 0.0082 S cm−1 which was lower compared to the membrane with 1.5 PWA: TEOS of specific conductivity 0.017 S cm−1. The specific conductivity of the membrane increased with increase in the temperature for both 0.5 and 1.5 molar ratio of PWA: TEOS with the calculated activation energy 18.9 and 8.8 kJ/mol, respectively.
Improving the properties of producer gas using high temperature gasification of rice husk in a pilot scale fluidized bed gasifier (FBG)
(Elsevier, 2019-01) Pandey, Jay
Biomass gasification is a well-studied thermo-chemical conversion route for the generating producer gas, a renewable energy carrier, for thermal and power applications as well as for bio-fuel production. High energy efficiency and clean gaseous fuel with low tar and suspended particulate matters (SPM) contents are some of the major challenges with biomass gasification. Herein, we report non-catalytic high temperature (720–855 °C) gasification of rice husk using fluidized bed gasifier (FBG). Producer gas mainly comprising of CO and H2 exhibited good higher heating value (HHV) and lower heating value (LHV) of 3.6 and 3.2 MJ/Nm3 respectively. Our experimental observations revealed that 790 °C is the optimum temperature for rice husk gasification with high carbon conversion efficiency (91.6%), thermal efficiency (75%) and high gas yield 2.7 m3/kg. High temperature gasification also resulted into reduced tar + SPM content (0.33 g/Nm3). Rice husk derived producer gas with good heating value and low tar + SPM content can be used as replacement of conventional fossil fuels for thermal applications in many processing industries.
In-situ growth of γ-Mn2O3 on activated carbon cloth for enhanced bifunctional electrocatalysis of ORR and OER
(Elsevier, 2025-09) Pandey, Jay
Developing cost-effective and high-performance electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for advancements in metal-air batteries, proton exchange membrane PEM fuel cells, and water-splitting systems. These systems require highly active and stable electrocatalysts to enhance the ORR and OER performance to increase the device's efficiency. Herein, we report the synthesis of γ-Mn2O3 nanoparticles doped onto activated carbon cloth (A-CC) (γ-Mn2O3/A-CC) via simple and scalable hydrothermal process followed by annealing. This work investigates the potential of γ-Mn2O3/A-CC as a bifunctional electrocatalyst for ORR and OER in alkaline media. In ORR condition, the γ-Mn2O3/A-CC electrocatalyst exhibited half-wave potential (E1/2) of 0.708 V, while in OER, the electrocatalyst exhibited overpotential of 522 mV at 10 mA cm−2 and low Tafel slope of 40.6 mV dec−1. The electrochemical performance of the synthesized catalysts is comparable to the state-of-the-art Pt/C and RuO2/C electrocatalysts. This study provides a comprehensive understanding of the electrocatalytic activity of γ-Mn2O3/A-CC, highlighting its potential application in advanced energy conversion devices.
Investigating degradation & mitigation strategies for proton conducting membrane in proton exchange membrane fuel cell: An approach to develop an active & stable membrane
(Elsevier, 2024-06) Pandey, Jay
Low-temperature proton exchange membrane fuel cells (PEMFCs) share many significant challenges in the performance, life-span, and industrial use of these membranes because of their degradation. This review synthesizes the current state of knowledge of the dominant degradation mechanisms acting on PEMs, namely mechanical stress, thermal degradation, and chemical attacks by reactive oxygen species (ROS). It is concluded that although mechanical degradation brought about by varying pressure and hydration cycles, membrane reinforcement with materials such as expanded polytetrafluoroethylene (ePTFE) and diverse composite membranes has somewhat mitigated the structural strength and toughness. Thermal and chemical degradation remains as principal challenges which are most often hastened by elevated temperatures and formation of reactive free radicals such as hydroxyl and hydrogen peroxide. Hence, to counteract chemical degradation, the addition of radical scavengers like cerium oxide (CeO2) and manganese-based additives can scavenge the destructive species even before this cause significant damage. Other new materials for PEM such as perfluorosulfonic acid (PFSA) composites have demonstrated enhanced resistance in chemical environments and a longer life. This includes research on innovative approaches such as introducing ionomers with improved thermal stability and evaluating hybrid organic-inorganic membranes in fighting the degradation mechanism of thermal degradations. This review brings out the need to understand the degradation mechanisms and advance mitigation strategies to ensure elongation of PEMFCs' life, thus paving a way for their reliability and feasibility as clean energy.
Investigating Membrane Degradation in Low-Temperature Proton Exchange Membrane Fuel Cell (PEMFC)
(Springer, 2023-03) Pandey, Jay
Due to emergence of clean, green and digital electric mobility, there is huge demand of electro-chemical devices such as battery driven electric vehicle or/and proton exchange membrane (PEM) fuel cell driven electric vehicles. Unfortunately, due to high cost, declined electro-chemical performance and poor durability, the global commercialization of electro-chemical conversion and storage devices is being hampered. PEM fuel cell driven electric vehicle has several advantages over battery driven electric vehicle such as cost, efficiency, operability and most importantly energy densities. However, the durability of components of PEM fuel cell such as membrane, electro-catalyst and bipolar plates is on of major challenges in PEM fuel cell. Therefore, understanding the degradation behavior and its mechanism in advanced functional materials such as proton conducting membrane followed by its mitigation is a crucial step to enhance the stability of PEM fuel cells. The detailed investigations were carried out to identify the electro-chemical, physical and process parameters causing membrane degradation under real-time operation of PEMFC. The membrane thinning, pin-hole formation, polymer backbone detachment and peroxide radical attacks are some of factors causing membrane degradation and affecting PEMFC performance.
Metal-free electrocatalyst for HER, OER and CO2RR: Towards green & sustainable energy solutions
(Elsevier, 2025-12) Pandey, Jay
Noble metals are frequently used in the quest for a practical and efficient way to address the world's energy needs. Unfortunately, the high cost and limited availability of noble metal electrocatalysts have prevented the broad application of renewable energy. In the quest for a sustainable energy source, metal-free systems have become a strong contender for the three essential electrocatalytic reactions: hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and carbon dioxide reduction reaction (CO₂RR). For the economical production of clean, renewable energy, metal-free electrocatalysis is essential. Over the past ten years, significant advancements in metal-free electrocatalysis have been made. This paper outlines the emergence of metal-free systems and illustrates their possible use in the renewable energy sector. Particularly, we started by providing an overview of the basic principles of electrochemical reactions. Later on, a study of metal-free electrocatalyst classification and recent advancements is performed; these include materials based on carbon (e.g., CNT, g-C3N4, graphene, etc.), covalent organic frameworks (e.g., triazine, porphyrin, thiadiazole, etc.), and others (biopolymer types, molecular types, etc.). Additionally, the application and synthesis process for the specific electrocatalytic reaction are described simultaneously. Overall, the essence of the key challenges and future outlooks to enhance the potential in metal-free electrocatalysis is provided. This review emphasizes the crucial role of metal-free electrocatalysts (MFEs) for reducing our dependency on fossil fuels and reaching carbon neutrality.
Non-noble metal-based electro-catalyst for the oxygen evolution reaction (OER): Towards an active & stable electro-catalyst for PEM water electrolysis
(Elsevier, 2024) Pandey, Jay
Among water electrolysis methods, proton exchange membrane electrolyzers (PEMWEs) stand out for their potential to generate high-purity hydrogen with remarkable efficiency and dynamic response, making them a cornerstone technology for the sustainable hydrogen economy. However, a key bottleneck lies in the slow reaction rate of the oxygen evolution reaction (OER) at the anode, a four-electron transfer process that significantly throttles the system's full potential. This significantly impacts overall efficiency and calls for unfolding stable, durable, and highly active electrocatalysts that are cost-effective. However, the inherent acidity generated by the OER itself complicates this task. Noble metal catalysts like iridium (Ir) and ruthenium (Rh), pure or combined with other elements, exhibit excellent activity in the acidic OER environment. However, their high cost hinders large-scale PEMWE deployment. Therefore, extensive research has concentrated on non-noble metal alternatives, particularly transition metal oxides (monometallic and polymetallic) and carbon-based materials. This comprehensive review meticulously examines the emerging progress in non-noble metal electrocatalysts designed for low-pH OER conditions within PEMWEs. Following an introductory classification of water electrolyzer technologies, it explores how factors such as structure and synthesis route modulate the crucial performance parameters across diverse catalyst groups. Drawing upon these insights, the review also evaluates the current challenges and outlines promising avenues for future research.
Performance of the vanadium redox-flow battery (VRB) for Si-PWA/PVA nanocomposite membrane
(Springer, 2016-05) Pandey, Jay
The performance of Si-PWA/PVA nanocomposite membrane in vanadium redox-flow battery (VRB) is reported. Structurally, the membrane consisted of a dispersion of sub-micron-sized silica immobilized phosphotungstic acid (Si-PWA) inorganic ion-exchanging phase in the continuous phase of cross-linked poly(vinyl alcohol) (PVA). SEM micrographs indicated the defect-free top surface of membrane with similar morphology of Nafion-115. Good ion selectivity and availability of ion-exchangeable sites were observed as indicated by higher transport number (0.89) and ion-exchange capacity (IEC) (1.20 meq g−1), respectively. Oxidative stability of the membrane was good in vanadium ion species (V4+, V3+, and V2+) but its stability in V5+ solution and Fenton’s reagent was slightly lower than Nafion-115. Vanadium ion permeability (0.69 × 10−7 cm min−1) of Si-PWA/PVA membrane was significantly lower than Nafion-115. Suitability for VRB with Si-PWA/PVA membrane was assessed from open-circuit voltage (OCV) decay which was lower compared to Nafion-115. Single-cell VRB with Si-PWA/PVA membrane exhibited lower voltage during charge and higher during discharge with excellent cyclic stability compared to VRB with Nafion-115.
PVDF supported silica immobilized phosphotungstic acid membrane for DMFC application
(Elsevier, 2014-09) Pandey, Jay
Silica immobilized phosphotungstic acid (Si-PWA) based inorganic–organic hybrid ion exchange membrane was used in direct methanol fuel cell (DMFC). Chemical composition of the ion exchanging phase of membrane was determined using energy dispersive spectroscopy (EDS). TGA analysis showed that the thermal stability of synthesized membrane was better than Nafion-117 and it also possessed excellent water holding capacity even at elevated temperature. The proton conductivity of the membrane increased upon increasing the PWA concentration in silica. Room temperature (25 °C) proton conductivity of the membrane was 4.3 m Scm− 1 and it increased to 10.1 m Scm− 1 upon increasing temperature to 60 °C. At 25 °C and 60% relative humidity, the peak power density of DMFC with synthesized membrane (21.6 m Wcm− 2) was much better than that of DMFC with Nafion-117 membrane (11 m Wcm− 2).
Recent Progresses in Membranes for Proton Exchange Membrane Fuel Cell (PEMFC) for Clean and Environmentally Friendly Applications
(IGI Global, 2019) Pandey, Jay
Fuel cell has become an emerging renewable energy device with potential to meet energy demand by portable and transport applications with zero-emission, easy operation, and compact design. The chapter provides an insight into design and development of membranes for PEMFCs and recent progresses made in membranes so far. Although majority of research has focused on fluorinated and non-fluorinated membranes, these polymeric membranes have showed deteriorated properties at elevated temperature (>80oC) and lower relative humidity (30%). Considering the major issues with polymeric membranes, the authors have reviewed inorganic-organic nanocomposite membranes showing improved physical and electrochemical properties at elevated temperature and lower relative humidity. Recently, metal-organic framework (MOF), a novel and unique material, has attracted tremendous attention due to their enhanced proton conductivity, easy functionality, and stability. MOFs have also exhibited excellent compatibility with different polymeric materials that are also discussed in this chapter.
Review on proton conducting membrane for PEM water electrolyser: A sustainable approach for green hydrogen production
(Elsevier, 2025-09) Pandey, Jay
Water electrolysis with proton exchange membranes (PEMs) holds great promise for producing green hydrogen, but the industry still leans heavily on expensive perfluorosulfonic acid membranes like Nafion. In this review, we dive into both established PFSA materials (Nafion, Aquivion, and PFSA–polymer composites) and emerging hydrocarbon-based alternatives (sulfonated poly(arylene ether sulfone), sulfonated poly(ether ether ketone), polyphenylene sulfone, and related systems). Rather than merely listing developments, we uncover how modifications at the molecular level-backbone chemistry, side-chain length, reinforcement by inorganic fillers, and crosslinking- translate into real gains in proton conductivity, mechanical strength, and chemical resilience. We also examine how these membranes behave under the harsh, acidic conditions of a working PEM water electrolyser, pinpointing the main pathways of performance loss (delamination, excessive swelling, and chemical degradation). Drawing on the latest studies, we highlight novel composite strategies-such as hybrid organic–inorganic networks and graft-copolymer architectures-that bring hydrocarbon membranes closer to PFSA benchmarks, often at dramatically lower cost. Finally, we sketch out future directions: designing acid-stable ion channels, refining scalable synthesis techniques, and integrating advanced reinforcement approaches to bridge the gap between lab-scale promise and industrial reality. By illuminating these structure–property links and proposing targeted research avenues, this review charts a clear path toward affordable, high-performance PEMs for a truly sustainable hydrogen economy.
Sodium borohydride-induced surface modification of manganese oxides for optimized ORR active electrocatalysts
(MDPI, 2025-04) Pandey, Jay
Manganese oxide octahedral molecular sieves (OMSs) are promising catalysts for oxygen reduction reactions (ORRs) due to their cost-effectiveness and durability. However, their practical application is hindered by inherent limitations, including low electrical conductivity and insufficient intrinsic catalytic activity.