{"id":3199,"date":"2020-03-13T09:19:51","date_gmt":"2020-03-13T09:19:51","guid":{"rendered":"https:\/\/www.gyanvihar.org\/journals\/?p=3199"},"modified":"2020-03-13T09:20:56","modified_gmt":"2020-03-13T09:20:56","slug":"hydrogen-storage-in-ni-intercalated-multiwall-carbon-nanotubes-a-review","status":"publish","type":"post","link":"https:\/\/www.gyanvihar.org\/journals\/hydrogen-storage-in-ni-intercalated-multiwall-carbon-nanotubes-a-review\/","title":{"rendered":"HYDROGEN STORAGE IN NI INTERCALATED MULTIWALL CARBON NANOTUBES\u2014A REVIEW"},"content":{"rendered":"

Volume 6, Issue 1, 2020, pp. 7-13<\/em><\/strong><\/span><\/p>\n

Shalini Dixit1,2<\/sup>, Gaurav Kumar Sharma1<\/sup>, Tarun Patodia1,2<\/sup>, Balram Tripathi2<\/sup><\/strong><\/span><\/p>\n

1<\/sup>Department of Physics, Suresh Gyan Vihar University, Jaipur<\/span><\/p>\n

2<\/sup>Department of Physics, S. S. Jain Subodh PG (Autonomous) College, Jaipur<\/span><\/p>\n

E-mail: shaliniytiwari@gmail.com<\/a> \u00a0, balramtripathi1181@gmail.com\u00a0<\/a><\/span><\/p>\n

Abstract<\/strong><\/span><\/p>\n

It is well known that three challenges of hydrogen economy, that is, production, storage, and transportation put tremendous stress on scientific community for the past several decades. Based on several investigations, reported in literature, it is observed that the storage of hydrogen in solid form is more suitable option to overcome the challenges like its storage and transportation. In this form, hydrogen can be stored by absorption (metal hydrides and complex hydrides) and adsorption (carbon materials). Compared to absorption, adsorption of hydrogen on carbon materials is observed to be more favorable in terms of storage capacity. Taking in to account of these facts, in this short review, an overview on hydrogen adsorption on Nickel intercalated carbon nanotubes is presented. Synthesis processes of carbon nanotubes is discussed in brief along with their hydrogen storage capacities at different operating conditions, and thermodynamic properties and reaction kinetics. In addition, different methods to improve hydrogen storage capacities of carbon nanotubes are presented in detail. Finally, comparison is made between carbon nanotubes and Nickel intercalated carbon nanotubes to estimate the amount of hydrogen that can be stored and retract practically.<\/span><\/p>\n

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  1. Introduction<\/strong><\/span><\/li>\n<\/ol>\n

    Renewable energy sources are becoming increasingly wide spread because of increasing energy consumption, decreasing fossil-based energy reserves, and intensifying environmental problems due to the use of fossil-based energy resources [1]<\/a>. Production of hydrogen energy has been increased in recent years because hydrogen energy does not harm the environment and can be produced in a sustainable way [2]<\/a>. The most important characteristics of hydrogen energy, namely the characteristics that distinguish it from other alternative energy sources, are its capacity to be widely produced, its low weight and energy density. Although many production methods exist for hydrogen energy, storage methods are still limited and problematic [3]<\/a>. Adsorbent materials have frequently been used in the storage of hydrogen energy in recent years to overcome these problems and the best performing of these adsorbent materials are carbon nanotubes [4,5]<\/a>. Carbon nanotubes store hydrogen up to 14 wt % due to their mechanical and electrical properties, large surface areas and abundant pore volume [6]<\/a>. There are single walled and multi walled carbon nanotubes produced in general, however producing a high volume of sin- gle walled carbon nanotubes is difficult, multi-walled carbon nanotubes (MWCNTs) are preferred to single-walled carbon nanotubes in hydrogen storage [7<\/a>–9]<\/a>.<\/span><\/p>\n

    Dillon et al. claimed that Single walled carbon nanotubes (SWCNTs) adsorb hydrogen between 5 and 10 wt % inside the pores of molecular dimensions [10]<\/a>. This result led to intense interest in carbon nanotubes for hydrogen adsorption. How- ever, Hirscher et al. was measured SWCNTs hydrogen adsorption capacity up to 0.01 wt % by thermal desorption spectroscopy at ambient pressures and temperature. They also noted that carbon nanotubes must be used in high quantities when storing hydrogen, otherwise the amount of stored hydrogen cannot be accurately measured [11]<\/a>. More- over, Zhu et al. found hydrogen adsorption capacity to be 5 wt% in MWCNTS at 300 K under 10 MPa pressure [12]<\/a>. However, Tibbetts\u00a0 et\u00a0 al.\u00a0 found\u00a0 that\u00a0 SWCNTs\u00a0 and\u00a0 MWCNTs uptake hydrogen less than 0.1 wt % under a pressure of 3.5 MPa and at room temperature [13]<\/a>. The differences in the results of the studies of the carbon nanotubes storage may be due to the weakness of the Wander Waals bonds which is established between hydrogen carbon nanotubes. The adsorbent capacity, and hence the hydrogen storage capacity of MWCNTs can be increased by adding various metals. Adding various metals and chemical compounds to the nanotubes increases the porosity, the dipole-dipole interaction, and thereby enables higher hydrogen storage capacity [14]<\/a>. Numerous studies have demonstrated that hydrogen uptake capacity is enhanced by doping metals and chemical compounds such as Ni, Pd, Pt, Li, TiO2<\/sub>, Al2<\/sub>O3<\/sub>, ZnO, BN [15<\/a>–17]<\/a>. The doped nanotubes are used also for many highly demanding applications such as lead removal, heavy metal removal, energy storage, biosensors, agriculture, field- emitting devices etc. [18<\/a>–21]<\/a>.<\/span><\/p>\n

    Furthermore, Zacharia et al. claimed that metal nanoparticles may increase hydrogen uptake approximately by 30% on carbon nanotubes via spill over mechanism. It was cited that the capacity of hydrogen adsorption on Pd & V doped MWCNTs was measured 0.69 wt % at 2 MPa by using Sievert’s like apparatus [22]<\/a>. Rather et al. indicated that TiO2<\/sub> doped carbon nanotubes adsorbed 0.40 wt % of hydrogen under pressure of 18 bar, also this result exhibited this nanotubes hydrogen adsorption capacity five times higher than purified CNTs. Studies conducted so far have shown that the surface modification of carbon nanotubes is done via metals and chemical compounds which is responsible for high amount of hydrogen storage [22<\/a>–24]<\/a>.<\/span><\/p>\n

    The hydrogen uptake capacity of Ni-MWCNTs was studied by Kim et al. and founded that Ni nanoparticles are spilled over on MWCNTs by incipient wetness impregnation method and the spreading of Ni nanoparticles over MWCNTs allows the hydrogen to make chemical bonds on the surface of MWCNTs. Additionally, they showed that 2.8% of Ni-MWCNTs deposited hydrogen approximately 1.2 wt % at ambient tem- perature [24]<\/a>.<\/span><\/p>\n

    Reyhani et al. observed that Ni nanoparticles display the maximum hydrogen adsorption capacity of 1.54 wt % at room temperature and atmospheric pressure. It was concluded that hydrogen molecules dissociate on metal particles and hydrogen is stored between the walled of nanotubes due to diffusion [25]<\/a>. However, because of the inconsistency of the level of hydrogen storage in these studies, we were eager to work on this field.<\/span><\/p>\n

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    Fig.1 Different solid-state hydrogen storage options [26]<\/span><\/p>\n

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    1. Experimental<\/strong> :<\/span><\/li>\n<\/ol>\n

      2.1 Materials<\/span><\/h3>\n

      MWCNTs of 10-20 nm in width and less than 2 \u00b5m length (99.99% purity) N<\/em>, N<\/em>-Dime- thylformamide (DMF) (99% purity), sulphuric acid (H2<\/sub>SO4<\/sub>) (99% purity), Ni,\u00a0 and nitric acid (HNO3<\/sub>) (65% purity) were purchased from Sigma Aldrich.<\/span><\/p>\n

      2.2 Preparation of Ni-doped MWCNTs<\/span><\/h3>\n

      150 mg MWCNTs were placed in a solution of 1 M of Ni(NO3<\/sub>)2<\/sub>6H2<\/sub>O and subjected to ultrasonification to prepare Ni-MWCNTs nanocomposites. The nanotubes were intercalated with Ni nanoparticles by an ultrasonicator for 1 h. Subsequently, the mixture was dispersed by using DMF using ultrasonicator for 3 h. Thereafter, the nanotubes were kept in an oven at a temperature of 200 \u25cbC for 2 h to remove any impurities.<\/span><\/p>\n

      2.3 Sample characterization<\/span><\/h3>\n

      The Zeiss Ultra Plus field emission scanning electron microscopy (FESEM), FEI 200S transition electron microscopy (TEM), Rigaku Ultima\u00a0 IV\u00a0 X-ray\u00a0 diffraction\u00a0 (XRD)\u00a0 using CuK\u03b1 radiation have been used to investigate the morphology of the synthesized Ni-MWCNTs. Ni-MWCNTs elemental composition investigated by elemental diffraction Bruker X- ray spectroscopy (EDX).<\/span><\/p>\n

      2.4 Hydrogenation studies<\/span><\/h3>\n

      Hydrogen\u00a0 \u00a0uptake\u00a0 \u00a0capacity\u00a0 \u00a0of\u00a0 \u00a0Ni-MWCNTs\u00a0 \u00a0was\u00a0 \u00a0<\/em>measured gravimetrically at different pressures (4, 8, 12, 16, 20 bar) using a Sievert’s-like apparatus. 150 mg of Ni-doped MWCNTs were placed in the storage tank. To remove impurities and possible moisture, 10-2<\/sup> torr vacuum was applied for 3 h at room temperature. Thereafter, the prepared nanocomposites interacted with hydrogen for 45 min at a flow rate of ~0.5 L\/ min, under 4 bar pressures (Fig. 1<\/a>).<\/span><\/p>\n

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      Fig.2\u00a0 Block diagram for Sievert\u2019s type hydrogen storage setup<\/span><\/p>\n

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      1. Hydrogen storage mechanism & Review Results<\/strong><\/span>\n