Incorporation of heteropoly acid, tungstophosphoric acid within MCM-41 via impregnation and direct synthesis methods for the fabrication of composite membrane of DMFC
“…In the case of bulk HPW (Fig. 5 , b), four characteristic bands at 1079, 983, 893, and 801 cm −1 are assigned to the stretching vibrations of P–O, W = O terminal , W–O corner –W, and W–O edge –W, respectively 26 , 31 , 32 . Figure 5 FT-IR spectra for a pure MCM-48 ( a ), bulk HPW ( b ), MCM-48-HPW ( c ), NH 2 -MCM-48-HPW ( d ), bulk MIP-PMAA ( e ) and SMIP-PMAA@MCM-48-HPW ( f ).…”
In this study, an efficient organic–inorganic hybrid nanocomposite was designed for deep oxidative/adsorptive removal of dibenzothiophene (DBT) from model and real fuel oils employing surface molecularly imprinted polymer (SMIP) and mesoporous silica nanoparticles (MSNs). On the surface of silanol-functionalized MCM-48-HPW prepared at different 12-tungstophosphoric acid (HPW wt%) as the oxidation catalyst, an imprinted polymethacrylic acid polymer (PMAA) as a selective adsorbent of DBT was formed using different amounts of DBT template. Then, various oxidant/sulfur molar ratios were applied during the desulfurization reactions according to the central composite design (CCD). The successful synthesis of the optimum SMIP-PMAA@MCM-48-HPW nanocomposite was confirmed by FTIR, XRD, N2-adsorption, SEM, TEM, TGA, and NMR techniques. The desulfurization percentage of the model oil reached 98.54% under the optimum conditions, and the catalyst percentage was found to be the most significant parameter for desulfurization efficiency. Comparison experiments showed that the combined role of oxidation and adsorption had an extensive impact on desulfurization efficiency. Under the optimized conditions, 96% DBT from gasoline was removed by the optimum nanocomposite. The optimum nanocomposite showed good stability and could be reused five times without a remarkable decrease in the desulfurization ability.
“…In the case of bulk HPW (Fig. 5 , b), four characteristic bands at 1079, 983, 893, and 801 cm −1 are assigned to the stretching vibrations of P–O, W = O terminal , W–O corner –W, and W–O edge –W, respectively 26 , 31 , 32 . Figure 5 FT-IR spectra for a pure MCM-48 ( a ), bulk HPW ( b ), MCM-48-HPW ( c ), NH 2 -MCM-48-HPW ( d ), bulk MIP-PMAA ( e ) and SMIP-PMAA@MCM-48-HPW ( f ).…”
In this study, an efficient organic–inorganic hybrid nanocomposite was designed for deep oxidative/adsorptive removal of dibenzothiophene (DBT) from model and real fuel oils employing surface molecularly imprinted polymer (SMIP) and mesoporous silica nanoparticles (MSNs). On the surface of silanol-functionalized MCM-48-HPW prepared at different 12-tungstophosphoric acid (HPW wt%) as the oxidation catalyst, an imprinted polymethacrylic acid polymer (PMAA) as a selective adsorbent of DBT was formed using different amounts of DBT template. Then, various oxidant/sulfur molar ratios were applied during the desulfurization reactions according to the central composite design (CCD). The successful synthesis of the optimum SMIP-PMAA@MCM-48-HPW nanocomposite was confirmed by FTIR, XRD, N2-adsorption, SEM, TEM, TGA, and NMR techniques. The desulfurization percentage of the model oil reached 98.54% under the optimum conditions, and the catalyst percentage was found to be the most significant parameter for desulfurization efficiency. Comparison experiments showed that the combined role of oxidation and adsorption had an extensive impact on desulfurization efficiency. Under the optimized conditions, 96% DBT from gasoline was removed by the optimum nanocomposite. The optimum nanocomposite showed good stability and could be reused five times without a remarkable decrease in the desulfurization ability.
“…Mesoporous particles such as zeolites are also good inorganic fillers. They show strong interfacial interactions within the polymer matrix owing to the particular surface area to volume ratios, and their pores are regulated to desire dimensions. − Incorporating layered materials into a polymer matrix can tune the proton-conducting pathways that favor fast proton migration compared to methanol molecules and ultimately shrink the methanol permeability. − Several fillers such as zeolites, sorbitol, and modernite, upon incorporation in the chitosan membrane, can reduce methanol crossover and shrink the free volume cavity. , Moreover, the rigid structure and hydrophilic nature of chitosan are excellent barriers to methanol crossover. For example, the methanol crossover can be overcome by using an efficient proton exchange membrane.…”
Section: Impact Of Inorganic Filler On Proton Exchange
Membranementioning
Chitosan is a naturally occurring polysaccharide with abundant biomass resources that attracts interest due to its unique physicochemical properties. The importance of chitosan has risen recently (a) because it is a renewable and biodegradable material and (b) because it has the ability to form a membrane. Therefore, chitosan is highly preferable for green energy applications. This review describes the most recent advancements in chitosan chemistry, emphasizing elemental modifying reactions like sulfonation, phosphorylation, phthaloylation, and chemical cross-linking. However, the major issues of the chitosan (CS)-based polymer electrolyte membrane (PEM) are attaining high proton conductivity, leakage across fuel cells, and durability. To overcome the above-mentioned issues, chitosan and the emerging class of inorganic materials 2-D transition metal dichalcogenides especially MoS 2 can be employed for proton-exchange membrane fuel cell applications. Surface functionalization of MoS 2 can open new pathways for fabricating CS/MoS 2 composite membranes. Current research also focuses on the following issues: (a) strategies for the development of PEM, (b) properties and structures of chitosan for fuel cell applications, and (c) chitosan utilization in different parts of the fuel cell. The present study also discusses progress and particular challenges that chitosan-based proton exchange membranes face. Moreover, strategies to control those issues and future aspects are discussed in detail.
“…Some Nafion binary inorganic composites have been studied in relation to DMFC, such as silicotungstic acid -SiO 2 [31] phosphotungstic acid-SiO 2 [31,95], phosphotungstic acid -mesoporous SiO 2 [96], and Pd-SiO 2 [97].…”
Section: Inorganic/nafion Compositesmentioning
confidence: 99%
“…6.20) [6,95,96]. Important conductivity increases were also obtained using sulfonated mesostructurated silica (MSU-F and MCM-41) [44], and silica nanoparticles with a sulfonated oligomer layer [50], as shown in Fig.…”
This chapter is devoted to summarize and discuss the main properties of ionomeric membranes used in direct alcohol PEM fuel cells. Although Nafion is the proton exchange membrane commonly used in methanol and other direct alcohol fuel cells, other proton and alkaline membranes are being investigated in order to improve the efficiency of DAFC. The goals in the development of this critical component of DAFC are: low cost, long durability, low alcohol permeability and high electrical conductivity. The last two properties can be combined in a single parameter, the membrane selectivity that accounts for the ratio between the proton and alcohol transport through the membrane. This parameter can be compared to that measured for Nafion to define a relative selectivity, which is a primary parameter to evaluate the potentiality of a ionomer material to be used in alcohol feed fuel cells.The vast catalogue of polymeric materials reviewed here included Nafion composite with inorganic and organic fillers, and non-fluorinated proton conducting membranes such as sulfonated polyimides, poly(arylene ether)s, polysulfones, poly (vinyl alcohol), polystyrenes, and acid-doped polybenzimidazoles. Anionexchange membranes are also discussed because of the facile electro-oxidation of alcohols in alkaline media and because of the minimization of alcohol crossover in alkaline direct alcohol fuel cells.The performance of different types of membranes in direct alcohol fuel cells, mainly methanol, are summarized and discussed in order to identify the most promissory ones. The lack of correlation between the relative selectivity and fuel cell performance of the membranes indicates that the architecture of the three
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