D.R. Naikwadi
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5 records found
1
Potassium-Doped Borophane Nanosheets
A Multifunctional Platform for Reversible Hydrogen Storage and Metal-Free Hydrogen Transfer
Journal article
(2026)
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Rajamohanan Sobhana Anju, Pankaj Kumar, Dhanaji R. Naikwadi, Bettina Baumgartner, Savi Chaudhary, Atul Bansode, Merel C. Konings, Freek Ariese, Prasad Gonugunta, More authors...
2D borophene has long been proposed as a promising hydrogen storage material, but experimental demonstrations remain limited to boron hydride sheets derived from MgB2. Here, we report the synthesis of potassium-doped borophane (BH) nanosheets, which serve as a high-capacity, reversible hydrogen storage platform and metal-free reducing agent. Through selective hydride transfer, the BH sheet efficiently converted levulinic acid (LA) to γ-valerolactone (GVL) under mild reaction conditions. Density functional theory (DFT) predicts a theoretical hydrogen content of 4.2 wt.% for the potassium-doped BH sheet. Remarkably, the dehydrogenated BH sheets can be partially regenerated under 50 bar H2, demonstrating reversible hydrogen storage. This work serves as an experimental validation for alkali-metal-modified borophanes acting as a multifunctional material for hydrogen storage and transfer, opening avenues for sustainable energy and other applications.
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2D borophene has long been proposed as a promising hydrogen storage material, but experimental demonstrations remain limited to boron hydride sheets derived from MgB2. Here, we report the synthesis of potassium-doped borophane (BH) nanosheets, which serve as a high-capacity, reversible hydrogen storage platform and metal-free reducing agent. Through selective hydride transfer, the BH sheet efficiently converted levulinic acid (LA) to γ-valerolactone (GVL) under mild reaction conditions. Density functional theory (DFT) predicts a theoretical hydrogen content of 4.2 wt.% for the potassium-doped BH sheet. Remarkably, the dehydrogenated BH sheets can be partially regenerated under 50 bar H2, demonstrating reversible hydrogen storage. This work serves as an experimental validation for alkali-metal-modified borophanes acting as a multifunctional material for hydrogen storage and transfer, opening avenues for sustainable energy and other applications.
Beyond metals
Tailored metal-free boron-oxy-carbide catalysts for CO2 hydrogenation
Journal article
(2026)
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Rajamohanan Sobhana Anju, Pankaj Kumar, Dhanaji R. Naikwadi, Merel C. Konings, Pascal G. Stam, Freek Ariese, Bettina Baumgartner, Atul Bansode, N. Raveendran Shiju, More authors...
The rational design of functional materials through targeted element-selection strategies offers a promising route for developing next-generation catalysts. Here, we employ this strategy to tackle critical challenges in the Reverse Water Gas Shift (RWGS) reaction, including catalyst deactivation, low CO selectivity, and the high cost of conventional transition-metal catalysts. Through this approach, we designed and synthesized a novel class of metal-free boron-oxy-carbide (BO) catalysts. The catalyst exhibited 100 % CO selectivity and maintained equilibrium CO₂ conversion without deactivation for over 250 h at 600 °C. Advanced characterization techniques, combined with density functional theory (DFT) calculations suggested that the ‘B-O-C triad’ within the BO lattice is responsible for the RWGS activity. These findings demonstrate the potential of BO catalysts as robust, scalable, and sustainable alternatives to state-of-the-art transition-metal-based catalysts for CO₂ valorization. We anticipate that these findings will provide a foundation for the design and activity of metal-free catalysts applicable to a diverse range of chemical transformations.
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The rational design of functional materials through targeted element-selection strategies offers a promising route for developing next-generation catalysts. Here, we employ this strategy to tackle critical challenges in the Reverse Water Gas Shift (RWGS) reaction, including catalyst deactivation, low CO selectivity, and the high cost of conventional transition-metal catalysts. Through this approach, we designed and synthesized a novel class of metal-free boron-oxy-carbide (BO) catalysts. The catalyst exhibited 100 % CO selectivity and maintained equilibrium CO₂ conversion without deactivation for over 250 h at 600 °C. Advanced characterization techniques, combined with density functional theory (DFT) calculations suggested that the ‘B-O-C triad’ within the BO lattice is responsible for the RWGS activity. These findings demonstrate the potential of BO catalysts as robust, scalable, and sustainable alternatives to state-of-the-art transition-metal-based catalysts for CO₂ valorization. We anticipate that these findings will provide a foundation for the design and activity of metal-free catalysts applicable to a diverse range of chemical transformations.
Breaking the temperature barrier
Unveiling the potential of ceria nanorods for low temperature thermochemical water splitting
Journal article
(2025)
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Dhanaji R.Naikwadi, Vaishnavi Ganesh, Hesham Sharaf, Michele Offidani, Stefania Albonetti, Nikolaos Dimitratos, Atul Bansode
Thermochemical Water-Splitting (TCWS) is a promising approach for generating clean hydrogen (H2) by employing the waste heat originating from different sources. High-temperature requirements and temperature swing approach hinder the widespread adoption of TCWS for clean hydrogen production. This study explores ceria nanorods (CeNRs) as a potential solution for overcoming these limitations. Herein, we report, the TCWS in a fixed bed reactor using CeNRs at low and constant temperature of 400 °C. We systematically explore the influence of synthesis parameters on the resulting CeNRs, including the selection of ceria precursor, effect of calcination, and their impact in TCWS. It was found that CeNRs prepared using cerium chloride as the precursor exhibited enhanced TCWS activity, resulting significantly higher total H2 yield 4.74 mL/g, at a constant temperature of 400 °C in three redox cycles. Moreover, X-ray Photoelectron Spectroscopy (XPS) analysis confirms the presence of both Ce3+ and Ce4+ states within the structure, with Ce3+ constituting approximately 30 % and Ce4+ accounting for approximately 70 % of the total cerium content. Additionally, Raman spectroscopy corroborates the presence of a higher concentration of oxygen vacancy which are beneficial for increasing the hydrogen production. We demonstrate that ceria in its nanorod structure having exposed higher proportions of (110) and (100) planes and higher concentration of oxygen vacancies is beneficial for lowering TCWS temperature as well as increasing the hydrogen yield.
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Thermochemical Water-Splitting (TCWS) is a promising approach for generating clean hydrogen (H2) by employing the waste heat originating from different sources. High-temperature requirements and temperature swing approach hinder the widespread adoption of TCWS for clean hydrogen production. This study explores ceria nanorods (CeNRs) as a potential solution for overcoming these limitations. Herein, we report, the TCWS in a fixed bed reactor using CeNRs at low and constant temperature of 400 °C. We systematically explore the influence of synthesis parameters on the resulting CeNRs, including the selection of ceria precursor, effect of calcination, and their impact in TCWS. It was found that CeNRs prepared using cerium chloride as the precursor exhibited enhanced TCWS activity, resulting significantly higher total H2 yield 4.74 mL/g, at a constant temperature of 400 °C in three redox cycles. Moreover, X-ray Photoelectron Spectroscopy (XPS) analysis confirms the presence of both Ce3+ and Ce4+ states within the structure, with Ce3+ constituting approximately 30 % and Ce4+ accounting for approximately 70 % of the total cerium content. Additionally, Raman spectroscopy corroborates the presence of a higher concentration of oxygen vacancy which are beneficial for increasing the hydrogen production. We demonstrate that ceria in its nanorod structure having exposed higher proportions of (110) and (100) planes and higher concentration of oxygen vacancies is beneficial for lowering TCWS temperature as well as increasing the hydrogen yield.
Journal article
(2025)
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Anastasios I. Tsiotsias, Eleana Harkou, Nikolaos D. Charisiou, Victor Sebastian, Dhanaji R. Naikwadi, Bart van der Linden, Atul Bansode, Dragos Stoian, Maria A. Goula, More authors...
Herein, the effect of the Ru:Ni bimetallic composition in dual-function materials (DFMs) for the integrated CO2 capture and methanation process (ICCU-Methanation) is systematically evaluated and combined with a thorough material characterization, as well as a mechanistic (in-situ diffuse reflectance infrared fourier-transform spectroscopy (in-situ DRIFTS)) and computational (computational fluid dynamics (CFD) modelling) investigation, in order to improve the performance of Ni-based DFMs. The bimetallic DFMs are comprised of a main Ni active metallic phase (20 wt%) and are modified with low Ru loadings in the 0.1–1 wt% range (to keep the material cost low), supported on Na2O/Al2O3. It is shown that the addition of even a very low Ru loading (0.1–0.2 wt%) can drastically improve the material reducibility, exposing a significantly higher amount of surface-active metallic sites, with Ru being highly dispersed over the support and the Ni phase, while also forming some small Ru particles. This manifests in a significant enhancement in the CH4 yield and the CH4 production kinetics during ICCU-Methanation (which mainly proceeds via formate intermediates), with 0.2 wt% Ru addition leading to the best results. This bimetallic DFM also shows high stability and a relatively good performance under an oxidizing CO2 capture atmosphere. The formation rate of CH4 during hydrogenation is then further validated via CFD modelling and the developed model is subsequently applied in the prediction of the effect of other parameters, including the inlet H2 concentration, inlet flow rate, dual-function material weight, and reactor internal diameter.
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Herein, the effect of the Ru:Ni bimetallic composition in dual-function materials (DFMs) for the integrated CO2 capture and methanation process (ICCU-Methanation) is systematically evaluated and combined with a thorough material characterization, as well as a mechanistic (in-situ diffuse reflectance infrared fourier-transform spectroscopy (in-situ DRIFTS)) and computational (computational fluid dynamics (CFD) modelling) investigation, in order to improve the performance of Ni-based DFMs. The bimetallic DFMs are comprised of a main Ni active metallic phase (20 wt%) and are modified with low Ru loadings in the 0.1–1 wt% range (to keep the material cost low), supported on Na2O/Al2O3. It is shown that the addition of even a very low Ru loading (0.1–0.2 wt%) can drastically improve the material reducibility, exposing a significantly higher amount of surface-active metallic sites, with Ru being highly dispersed over the support and the Ni phase, while also forming some small Ru particles. This manifests in a significant enhancement in the CH4 yield and the CH4 production kinetics during ICCU-Methanation (which mainly proceeds via formate intermediates), with 0.2 wt% Ru addition leading to the best results. This bimetallic DFM also shows high stability and a relatively good performance under an oxidizing CO2 capture atmosphere. The formation rate of CH4 during hydrogenation is then further validated via CFD modelling and the developed model is subsequently applied in the prediction of the effect of other parameters, including the inlet H2 concentration, inlet flow rate, dual-function material weight, and reactor internal diameter.
Urbanization and industrialization have significantly increased the demand for energy, predominantly sourced from nonrenewable fossil fuels such as natural gas, coal, and oil. Biomass-based biofuel has been considered as a suitable and sustainable option to suffice the growing needs. Among several biomass conversion pathways, thermochemical route through pyrolysis has received a lot of attention due to a good yield of liquid bio-oil and the direct conversion of biomass to value-added chemicals. This chapter describes the compositional structure of biomass and compares the physical, chemical, biochemical, and thermochemical techniques used for biomass conversion into useful products. The thermochemical pyrolysis process and the liquid bio-oil obtained as product are discussed to analyze its closeness in terms of compatibility with conventional fuel. Though pyrolytic bio-oil is produced in sufficient quantity, it is not suitable to replace the available nonrenewable energy resources due to the presence of high oxygen functionalities. Therefore, upgradation of this bio-oil is necessary to meet commercial needs and replace conventional energy sources. Various pyrolysis oil upgrading methods to produce high-quality fuel and chemicals with special emphasis on the hydrodeoxygenation reaction are discussed here. This chapter provides a special emphasis on the hierarchical zeolites, which are found to be promising catalysts due to their lesser deactivation and high reaction rate as compared with commercial zeolites.
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Urbanization and industrialization have significantly increased the demand for energy, predominantly sourced from nonrenewable fossil fuels such as natural gas, coal, and oil. Biomass-based biofuel has been considered as a suitable and sustainable option to suffice the growing needs. Among several biomass conversion pathways, thermochemical route through pyrolysis has received a lot of attention due to a good yield of liquid bio-oil and the direct conversion of biomass to value-added chemicals. This chapter describes the compositional structure of biomass and compares the physical, chemical, biochemical, and thermochemical techniques used for biomass conversion into useful products. The thermochemical pyrolysis process and the liquid bio-oil obtained as product are discussed to analyze its closeness in terms of compatibility with conventional fuel. Though pyrolytic bio-oil is produced in sufficient quantity, it is not suitable to replace the available nonrenewable energy resources due to the presence of high oxygen functionalities. Therefore, upgradation of this bio-oil is necessary to meet commercial needs and replace conventional energy sources. Various pyrolysis oil upgrading methods to produce high-quality fuel and chemicals with special emphasis on the hydrodeoxygenation reaction are discussed here. This chapter provides a special emphasis on the hierarchical zeolites, which are found to be promising catalysts due to their lesser deactivation and high reaction rate as compared with commercial zeolites.