Department of Chemical Engineering
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Item Surface-engineered manganese oxide via sodium borohydride for optimized ORR active electrocatalyst(ACS, 2025-10) Pandey, JayManganese oxide octahedral molecular sieves (OMS) have garnered attention as promising electrocatalysts for oxygen reduction reactions (ORRs) due to their cost-effectiveness as well as durability. However, their practical application is limited by inherent drawbacks such as low electrical conductivity and insufficient intrinsic catalytic activity. To overcome these challenges, we employed a surface reduction etching treatment using NaBH4 to optimize the oxygen vacancy of OMS. The treatment with a 6 mmol/L NaBH4 solution significantly increased the number of oxygen vacancies on the surface of OMS, which serve as crucial active sites facilitating the adsorption and dissociation of oxygen molecules, thereby enhancing ORR activity. Furthermore, the treatment effectively regulated the Mn3+/Mn4+ ratio on the nanosphere surface, further promoting catalytic efficiency by facilitating the transfer of electrons during the ORR process. Notably, the optimized OMS material exhibited a remarkable half-wave potential of 0.661 V, highlighting its improved performance and potential as a suitable replacement for traditional platinum-based catalysts. This straightforward and scalable method unlocks the potential of OMS materials for practical applications, offering a promising solution for energy storage as well as conversion technologies that require efficient ORR catalysts.Item Metal-free electrocatalyst for HER, OER and CO2RR: Towards green & sustainable energy solutions(Elsevier, 2025-12) Pandey, JayNoble 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.Item Synthesis of proton conducting and highly stable pwa-zrp-doped composite membrane for proton exchange membrane fuel cell(ASME, 2023-02) Pandey, JayMechanically stable, proton-conducting, and very cost-effective nanocomposite membrane was synthesized successfully using a simple and scalable phase-inversion approach. Phosphotungstic acid (PWA) and zirconium phosphate (ZRP) were synthesized using sol–gel and co-precipitation method, respectively. PWA-ZrP nanoparticles showed remarkable compatibility with cross-linked poly(vinyl alcohol) (c-PVA) and thus forming uniform and defect-free composite membrane of thickness ∼100–120µm. Doped PWA-ZRP nanoparticles into c-PVA membrane led to introduced bronsted acidic sites, and thereby, drastic improvement in proton conductivity of membrane was observed. Composite membrane revealed excellent water-holding capabilities with proton conductivity of 5.2 × 10−5 Scm−1 under fully hydrated conditions (i.e., 98% relative humidity). The synthesized proton-conducting nanocomposite membrane was demonstrated as a potential advanced functional solid electrolyte for possible application in proton exchange membrane fuel cell.Item 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, JayAmong 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.Item Development of machine learning based model for low-temperature PEM fuel cells(Elsevier, 2024-09) Pandey, JayLow-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.Item Electrocatalyst for the oxygen reduction reaction (ORR): towards an active and stable electrocatalyst for low-temperature PEM fuel cell(Springer, 2024-08) Pandey, JayGreen 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.Item Synthesis of manganese-doped N-C bifunctional electrocatalyst for low-temperature PEM fuel cell(Springer, 2025-01) Pandey, JayPEM fuel cell plays a vital role in ensuring a sustainable future in the energy domain. Electrochemical activities of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts induce a strong impact on the performance of PEM fuel cells. Bifunctional catalysts capable of facilitating both ORR and OER are crucial for enhancing the overall efficiency and durability of these electrochemical devices. Commercially, Pt/C and RuO2/C are the available options for PEM fuel cells, which makes the device very costly. Herein, we have prepared a Mn-doped N-C electrocatalyst that shows comparable bifunctional performance as commercial catalysts. The use of naturally occurring sources such as picolinic acid for the synthesis of catalysts over the expensive raw material helps in bringing down the cost. Synthesized electrocatalyst contains mixed oxidation states of Mn (Mn, Mn2+, Mn3+, Mn4+), follows 4e− path during the ORR, and for OER, the measured Tafel slope was 19.8 mv/dec with Eoer-10 of 1.617 V and ΔE of 1.004 V, showing promising potential for use in PEM fuel cells.Item 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, JayLow-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.Item Sodium borohydride-induced surface modification of manganese oxides for optimized ORR active electrocatalysts(MDPI, 2025-04) Pandey, JayManganese 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.Item In-situ growth of γ-Mn2O3 on activated carbon cloth for enhanced bifunctional electrocatalysis of ORR and OER(Elsevier, 2025-09) Pandey, JayDeveloping 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.