Browsing by Author "Anant Prakash Pandey"

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Economical synthesis of highly efficient and tunable carbon aerogels for enhanced storage of CO2 emitted from energy sources
(John Wiley and Sons Ltd, 2021) Ashish Bhatnagar; Anant Prakash Pandey; M. Sterlin Leo Hudson; Pawan K. Soni; Satish K. Verma; Vivek Shukla; V. Sekkar; Manoj Tripathi; O.N. Srivastava
The present investigation reports the synthesis of Carbon Aerogel (CA) with varying pore size and surface area by changing the initial precursor that is, Resorcinol (R) and novel Catalyst (triethyl amine [TEA]) (C) ratio (R/C). The catalyst, TEA allows the gel to dry with negligible shrinkage. The R/C ratio has been kept 1000, 2000 and 3000. The CA with R/C = 1000 has the lowest pore size 1.93 nm, the highest surface area (369.14 m2/g) and the highest CO2 uptake of 24.40 wt.% (5.54 mmol/) at 40 atm CO2 pressure. The activated version of optimum CA (R/C = 1000) has been found to have an average pore diameter ~ 1.91 nm and CO2 uptake capacity of 29.56 wt% (6.71 mmol/g) at 25°C which is one of the highest CO2 storage capacity of CAs reported so far. Thus, the present manuscript put forward highly efficient and tunable CAs for enhanced CO2 storage. © 2020 John Wiley & Sons Ltd
Highly efficient catalytic derived synthesis process of carbon aerogel for hydrogen storage application
(Elsevier Ltd, 2023) Anant Prakash Pandey; M.A. Shaz; V. Sekkar; R.S. Tiwari
For the present work, resorcinol-formaldehyde (R–F) aerogels were synthesized through both acid (nitric acid) and base (sodium carbonate) catalyzed sol-gel process followed by supercritical drying (SCD) as well as ambient pressure drying (APD). RF aerogels were carbonized at high temperatures to form carbon aerogels. The effect of the catalyst type and drying methods on the final characteristics were studied in detail. Microstructural and textural characteristics were evaluated through XRD, SEM, BET, RAMAN, FTIR, and TEM techniques. It was found that the combination of base catalysis and SCD delivered a higher micropore density and more uniform pore distribution. The CAs prepared under such conditions displayed a hydrogen uptake of 0.80 wt% at room temperature and 2.85 wt% at liquid nitrogen temperature (77 K). © 2022 Hydrogen Energy Publications LLC
Hydrogen storage properties of carbon aerogel synthesized by ambient pressure drying using new catalyst triethylamine
(Elsevier Ltd, 2020) Anant Prakash Pandey; Ashish Bhatnagar; Vivek Shukla; Pawan K. Soni; Sweta Singh; Satish K. Verma; M. Shaneeth; V. Sekkar; O.N. Srivastava
In this paper, we report here the hydrogen storage capacity of activated carbon aerogel synthesized by ambient pressure drying using a new catalyst. The carbon aerogel (CA) has been synthesized by the sol-gel method using resorcinol (R) and formaldehyde (F). For drying of RF wet gel instead of expensive and unsafe supercritical process, we have used ambient pressure drying. To avoid shrinkage which may occur due to this mode of drying, instead of usual catalyst (C): Na2CO3, organic catalyst triethylamine (TEA), which is known to be a condensing agent has been used. In order to find out the effect of change of R/C ratio on hydrogen sorption, three different R/C namely CA 1000, CA 2000, and CA 3000 were taken. Structural and microstructural details have been studied employing XRD, SEM, TEM, nitrogen adsorption, FTIR, and Raman spectroscopy. TEM and nitrogen adsorption studies have revealed that aerogel with R/C 1000 exhibits a higher degree of micropore density. The hydrogen storage capacities for all R/C ratios have been determined. It has been found that carbon aerogel (CA) with R/C = 1000, exhibits the highest hydrogen adsorption capacity out of the three aerogels. At liquid nitrogen temperature, the hydrogen storage capacity of aerogel with R/C = 1000 for the as-synthesized and activated carbons have been found to be 4.00 wt % and 4.80 wt %. A viable reason for the occurrence of high hydrogen storage capacity at liquid nitrogen temperature for aerogel with R/C = 1000 has been put forward. © 2020 Hydrogen Energy Publications LLC
Low cost and efficient counter electrode for solid-state natural dye-sensitized solar cells
(Springer Science and Business Media B.V., 2023) Priyanka Chawla; Anant Prakash Pandey; Kumari Pooja; Mridula Tripathi
Current studies on dye-sensitized solar cells focus on using low cost materials with high efficiency. Platinum is the most desirable material for the counter electrode of dye-sensitized solar cells but it is an expensive material that limits its use. To reduce the cost, carbon-based materials are focused on as it proves to be the best material as far as cost is concerned. We investigated the use of composite paste of multiwall carbon nanotubes and activated carbon based on coconut fiber (1:1) for the preparation of counter electrodes. In place of liquid electrolyte, we have prepared solid polymer electrolyte based on Polyvinylidene fluoride (PVDF) due to its exceptional properties with graphite as filler. The obtained conductivity was found to be 5.63 × 10−3 S cm− 1. Anthocyanin pigment obtained from mulberry is being used as a natural dye. The addition of indium oxide (In2O3) to titanium dioxide (TiO2) increased the spectrum response of TiO2, which led to greater efficiency. The obtained efficiency was found to be 3.3 which is excellent in the case of natural dye-sensitized solar cells. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.
Multiple improvements of hydrogen sorption and their mechanism for MgH2 catalyzed through TiH2@Gr
(Elsevier Ltd, 2020) Satish Kumar Verma; Ashish Bhatnagar; Vivek Shukla; Pawan Kumar Soni; Anant Prakash Pandey; Thakur Prasad Yadav; Onkar Nath Srivastava
The present investigation reports the effect of TiH2 templated over graphene (TiH2@Gr) on the hydrogen sorption characteristics of MgH2/Mg. The as synthesized TiH2@Gr leads to significant effect on sorption in MgH2 by the following effects: the first is dehydrogenation of MgH2–TiH2@Gr, which leads to the conversion of some part of TiH2 into TiH1.924. TiH2 together with TiH1.924 works as a better catalyst than TiH2 alone. The second is ball-milling of TiH2@Gr, which produces defective graphene, which also works as co-catalyst. The third is anchoring of TiH2 on graphene, which does not allow the catalyst to agglomerate. The catalytic effect of TiH2@Gr on MgH2 is found to be better than Ti@Gr and TiO2@Gr. The onset desorption temperature for MgH2–TiH2@Gr is ~204 °C, which is 31 °C and 36 °C lower than MgH2–Ti@Gr, MgH2–TiO2@Gr respectively. The better catalytic behavior of TiH2@Gr also persists during de/re-hydrogenation kinetics and cycling study of MgH2. The feasible mechanism for superior catalytic for TiH2@Gr on MgH2 has been put forward. © 2020 Hydrogen Energy Publications LLC
Synergistic effect of CNT bridge formation and spillover mechanism on enhanced hydrogen storage by iron doped carbon aerogel
(Elsevier Ltd, 2023) Anant Prakash Pandey; M.A. Shaz; V. Sekkar; R.S. Tiwari
In the present, enhanced hydrogen sorption over activated iron-doped carbon aerogel (CA) through the spillover effect was taken up. Iron doped carbon aerogel was prepared through sol-gel polymerization of resorcinol-formaldehyde (R–F) with sodium carbonate as a catalyst. Iron doping was made at 1, 5, and 10 wt % levels. It has been further inferred that the presence of nano iron caused carbon nanotube (CNT) formation in the carbon matrix during the carbonization and activation processes. Fe doped CAs were characterized by XRD, SEM, BET, FTIR, and TEM. Hydrogen sorption by 1, 5, and 10% Fe doped CAs at liquid nitrogen temperature (77K) and up to 25 atm. had storage capacities as 1.47 wt%, 1.38 wt%, and 1.28 wt%, respectively. Activation of CAs brought a significant increase in the storage capacity (∼3.80 wt%), which could have been driven by the presence of CNT in the matrix and an increase in the microporosity on activation. © 2022 Hydrogen Energy Publications LLC
Three-dimensional graphene aerogel decorated with nickel nanoparticles as additive for improving the hydrogen storage properties of MgH2
(Elsevier Ltd, 2025) Sweta Singh; Ashish Bhatnagar; Vivek Shukla; Anant Prakash Pandey; Mohammad Abu Shaz
In the present study, three-dimensional graphene aerogel (GA) and nickel-decorated graphene aerogel (Ni@GA) were synthesized using the sol-gel technique followed by supercritical CO2 drying. These synthesized materials exhibit exceptional additive performance for hydrogen sorption in magnesium hydride (MgH2). Hydrogen sorption experiments indicate that combining Ni@GA as an additive with MgH2 demonstrates enhanced hydrogen storage properties compared to ball-milled (B.M) MgH2 and MgH2 with 5 wt% of GA (MgH2:GA). The results show the onset desorption temperature of the MgH2 with 5 wt % of Ni@GA (MgH2:Ni@GA) is 221 °C, whereas the onset desorption temperature of B.M. MgH2 and MgH2: GA is ∼260 °C and 358 °C, respectively. In view of kinetic performance, B.M. MgH2 and MgH2: GA absorb only 1.50 wt% and 5.2 wt% of hydrogen, respectively, but MgH2:Ni@GA absorbs 5.71 wt% hydrogen within 2.2 min at 290 °C under 15 atm hydrogen pressure. Therefore, MgH2:Ni@GA exhibits improved kinetics compared to B.M. MgH2 and MgH2:GA. Moreover, MgH2: Ni@GA has exceptional cyclic stability, maintaining minor change even after 27 cycles of de/rehydrogenation. The formation enthalpy of MgH2: Ni@GA is 68.71 kJ/mol of hydrogen. A plausible working mechanism of Ni@GA as an additive on MgH2 has been proposed, relying on the utilization of X-ray diffraction (XRD), electron microscopy, and X-ray photoelectron spectroscopy (XPS) studies. © 2024 Hydrogen Energy Publications LLC