Preparation and characterization of hydrophobic platinum-doped carbon aerogel catalyst for hydrogen isotope separation

Singh, M. K.; Singh, Rashmi; Singh, Ashish; Kohli, Deepak; Deshpande, Uday; Gupta, Pooja

doi:10.1007/s12034-014-0100-8

Cited by 7 publications

(2 citation statements)

References 15 publications

(12 reference statements)

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“…However, PTFE coatings are used for hydrophobic Pt catalysts for the liquid‐phase catalytic exchange reaction between water and hydrogen gas. Here, porous PTFE prevents the formation of a liquid water film on Pt, which would be a kinetic barrier, but it allows access of gaseous species (e.g., hydrogen and gaseous water) to the catalytically active surface . Electronegative atoms such as O and Cl are known to be poisons for the adsorption of hydrogen .…”

Section: Figurementioning

confidence: 99%

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

et al. 2016

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The catalytic activity of Pd surfaces towards hydrogen desorption was significantly improved by a nanometer‐thin polytetrafluoroethylene (PTFE) layer, as shown by an enhancement in the permeability of a Pd membrane coated on the permeate side. The origin of this effect was found to be due to a lowering of the barrier for hydrogen desorption, as evidenced by a change in the rate‐limiting mechanism of hydrogen permeation through the membrane from desorption (un‐coated) to diffusion controlled. In situ X‐ray photoelectron spectroscopy (XPS) revealed the electronic structure of the sputtered PTFE. Apart from C–Fn subunits (n=1, 2, 3), we found that nonsaturated carbon atoms became hydrogenated during hydrogen permeation, which was indicative of an interaction between Pd and PTFE. This interaction was weak; no Pd−F bonds were formed. We thus attributed the effect to an increase in the hydrophobicity of the surface by the porous PTFE layer and to a promoter effect of hydrogen desorption as a result of electrostatic interactions between chemisorbed hydrogen and physisorbed PTFE.

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Section: Figurementioning

confidence: 99%

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

et al. 2016

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“…In our earlier studies we had mixed PtCA powder synthesized by in situ sol-gel polymerization method with colloidal PTFE solution and coated on Dixon rings to obtain the hydrophobic catalyst 12 . This catalyst showed good catalytic activity for hydrogen isotope exchange in atmospheric pressure conditions.…”

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confidence: 99%

Assessment of Human Exposure to Dissolved Radon in Groundwater around the Uranium Industry of Jaduguda, Jharkhand, India

Sethy¹,

Jha²,

Ravi³

et al. 2015

Current Science

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Radium, thorium, and radioactive lead isotopes in groundwaters: application to the in situ determination of adsorptiondesorption rate constants and retardation factors. Water Resour. Res., 1982Res., , 18, 1663Res., -1675. Kozowska, B., Walencik, A., Dorda, J. and Zipper, W., Radon in groundwater and dose estimation for inhabitants in spas of the Sudety Mountain area, Poland. Appl. Radiat. Isot., 2010, 68, 854-857. 19. Zouridakis, N., Ochsenkühn, K. M. and Savidou, A., Determination of uranium and radon in potable water samples. CATALYSED exchange of deuterium (D) between hydrogen (H) gas and liquid water (liquid phase catalytic exchange (LPCE) reaction) using bi-thermal hydrogen water (BHW) process is receiving considerable attention for heavy water production 1 . This is because it is more energy-efficient and environment-friendly compared to the existing 'girder sulphide' and 'ammonia-hydrogen' processes. The catalysed exchange involves two stepsfirst, deuterium exchange between hydrogen gas and water vapour at the catalytic site and subsequently equilibration of deuterated water vapour with liquid water at gas-liquid interface, which results in the transfer of deuterium from gas to liquid phase. Success of the process requires simultaneous presence of H 2 gas and water vapour at the catalytic site and easy accessibility of liquid water to water vapour involved in isotopic exchange reaction. However, because the solubility of H 2 gas in water is poor, if the catalytic site is covered with liquid water, the exchange of deuterium between hydrogen gas and water vapour is highly impeded 2 . Therefore, a primary requirement for the LPCE process is that the catalyst should allow access of gaseous reactants to the catalytic RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 109, NO. 10, 25 NOVEMBER 2015 1861 However, these show good activity only up to atmospheric pressure and rapidly lose activity as the pressure is increased above atmospheric pressure. This has limited the use of the LPCE process for relatively low-throughput applications like removal of tritium from heavy water of the moderator used in pressurized heavy water reactor operation 10 . The reduction in catalyst activity at higher pressure is believed to arise due to ingression of water at such pressure through pores in the fibrous network or mesh structure of the commonly used hydrophobic binders like PTFE and SDBC. Indeed, the studies carried out by Malhotra et al. 11 showed how the size and distribution of pore in binder contribute to the loss of activity at higher pressure. To address this issue, we have explored different approaches like high-pressure melting of PTFE film, PTFE overcoat, coating of other binders like polyvinylidenedifluoride (PVDF), perfluoroalkoxyalkanes (PFA), etc. to control the porosity of the film. These studies have led us to the successful development of hydrophobic platinumdoped carbon aerogel (PtCA) catalyst that shows good catalytic activity even up to 20 bar.In our earlier studies we had mixed PtCA powder synthesized...

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Residence time distribution study in a pilot-scale liquid phase catalytic exchange (LPCE) column packed with a mixture of hydrophobic and hydrophilic catalysts

Goswami

Shenoy

Mistry

et al. 2021

Applied Radiation and Isotopes

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Preparation and characterization of hydrophobic platinum-doped carbon aerogel catalyst for hydrogen isotope separation

Cited by 7 publications

References 15 publications

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

Assessment of Human Exposure to Dissolved Radon in Groundwater around the Uranium Industry of Jaduguda, Jharkhand, India

Residence time distribution study in a pilot-scale liquid phase catalytic exchange (LPCE) column packed with a mixture of hydrophobic and hydrophilic catalysts

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