Enhanced proton transport properties of Nafion via functionalized halloysite nanotubes

Ressam, Ibtissam; Kadib, Abdelkrim El; Lahcini, Mohammed; Luinstra, Gerrit A.; Perrot, Hubert; Sel, Ozlëm

doi:10.1016/j.ijhydene.2018.05.025

Cited by 21 publications

(24 citation statements)

References 53 publications

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“…The lowest contact angle was obtained for S‐2.5/SPS48*‐0.1 membrane, which can be related to the hydrophilic nature of the SPS 16 . The contact angle of the commercial Nafion117 membrane was reported as 89° 57 which is higher than the neat SPEEK and modified membranes in this research. The suitable hydrophilicity of the fabricated membranes can be related to the DS of SPEEK (S‐2.5) which is the base polymer for membrane fabrication.…”

Section: Resultsmentioning

confidence: 50%

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

Samaei

Bakeri

Lashkenari

2020

J of Applied Polymer Sci

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In this research, the preparation of low cost proton exchange membranes (PEMs) based on sulfonated poly ether ether ketone (SPEEK) for application in the microbial fuel cells (MFCs) is studied. Sulfonated polystyrene (SPS) and phosphotungstic acid (PWA) were employed to improve the performance of PEM through the creation of more proton pathways. At first, the sulfonation of PEEK and polystyrene were performed through two modified methods to obtain uniform and high degree of sulfonation (DS) of the polymers and then, the PEMs were prepared through the solution casting method. Accordingly, the formation of uniform skin layer was confirmed by the SEM micrographs. Blending the aforementioned additives to the SPEEK polymer solution significantly enhanced the proton conductivity, water uptake and durability of the modified membranes. The proton conductivities of SPEEK/SPS and SPEEK/PWA membranes at additive/SPEEK weight ratio of 0.15 were 45.3% and 26.2% higher than that of the commercial Nafion117 membrane, respectively. Moreover, the degradation times for the abovementioned modified membranes were 140 and 350 min which indicated satisfactory oxidation stability. Besides, the aforementioned membranes exhibited two times more water uptake compared to the neat SPEEK membrane. Finally, SPEEK/SPS and SPEEK/PWA membranes produced 68% and 36% higher maximum power in the MFC, compared to the commercial Nafion117 membrane. Therefore, the fabricated PEMs are potentially suitable alternatives to be used in the fuel cell applications.

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Section: Resultsmentioning

confidence: 50%

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

Samaei

Bakeri

Lashkenari

2020

J of Applied Polymer Sci

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“…The edges of nanotubes and surface's defects contain silanol and aluminol groups. 26 Halloysite functionalization with silanes takes place both on the outer and in the inner surfaces with the preferential graing on more reactive inner lumen. 27 Thus, we took into account the potential slow down of Fmoc release and its diffusion retardation from sterically hidden cavity, thus studied kinetics of deprotection in the time interval of 1-5 h. Five HNT-APTES-Fmoc samples were mixed separately with an excess of 20% solution of piperidine in EtOH at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Quantification of amino groups on halloysite surfaces using the Fmoc-method

et al. 2020

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“…In some cases, however, aggregated nanoclays can decline the performance of the composites. Hence, research groups have developed various methods to improve the dispersion state, interface, and proton conductivity of ionomer/halloysite nanotube composite, for example by surface modification such as sulfonation [37,[39][40][41], amination [37,[41][42][43], or impregnation with phosphotungstic acid (PWA) [44]. Optimizing the blending time of the casting dispersion is also of major importance [45].…”

Section: Introductionmentioning

confidence: 99%

Composite short-side-chain PFSA electrolyte membranes containing selectively modified halloysite nanotubes (HNTs)

et al. 2021

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Aquivion membrane displays improved properties as compared to Nafion membrane, partly due to shorter side chains. However, some improvements are still necessary for proton exchange membrane fuel cell to operate at low relative humidity. To overcome this drawback, the addition of clay nanoparticle into the Aquivion matrix can be considered. In this study, different composite mem-branes have been prepared mixing short-side-chain PFSA (perfluorosulfonic acid) Aquivion and selectively modified halloysite nanotubes for PEMFC low relative humidity operation. Halloysites were grafted with fluorinated groups, sulfonated groups, or perfluoro-sulfonated groups on inner or outer surface of the tubes. The obtained composite membranes showed improved properties, especially higher water uptake associated with reduced swelling and better mechanical strength compared to pristine Aquivion membrane and commer-cially available Nafion HP used as reference. The best performance in this study was obtained with Aquivion loaded with 5 wt% of pretreated perfluoro-sul-fonated halloysite. The composite membrane, referred to as Aq/pHNT-SF5, displayed the largest water uptake and proton conductivity among the panel of membranes tested. The chemical stability was not affected by the presence of halloysite in the Aquivion matrix.

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Enhanced proton transport properties of Nafion via functionalized halloysite nanotubes

Abstract: agreement with the σH + enhancement, the activation energy is lower than that of native Nafion indicating that the proton transport is facilitated in the presence of-SO3H modified HNTs, probably due to an improved connectivity and arrangement of ionic conducting domains.

Cited by 21 publications

References 53 publications

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

Quantification of amino groups on halloysite surfaces using the Fmoc-method

Composite short-side-chain PFSA electrolyte membranes containing selectively modified halloysite nanotubes (HNTs)

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