NaOH modified P(acrylamide) hydrogel matrices for in situ metal nanoparticles preparation and their use in H₂ generation from hydrolysis of NaBH₄

Abstract

Crosslinked poly(acrylamide) (p(AAm)) as neutral hydrogel is synthesized via photo polymerization technique, and the amide groups within p(AAm) matrices are converted to strongly ionizable carboxylic acids groups via facile modification route by simple treatment of NaOH to obtained NaOH‐p(AAm) hydrogels. Because of the highly ionizable nature of carboxylate groups within mod‐p(AAm), the swelling and metal ion absorbing capacities are increased tremendously, almost 40 and 7.5 folds, respectively. The Co(II) and Ni(II) metal ions are loaded into NaOH‐p(AAm) hydrogels, and are treated with NaBH4 to form corresponding metal nanoparticles in situ within mod‐p(AAm) matrices, and used in H2 generation production from hydrolysis of NaBH4. Various parameters such as functionality of polymeric matrices, the kinds and the amount of metal nanoparticles, and the temperature effecting the H2 generation are investigated. Comparable low Ea with the similar researches in the literature, Ea = 20.07 ± 0.05 kJ mol−1 is obtained in NaBH4 hydrolysis catalyzed by NaOH‐p(AAM)‐Co composite system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41106.

RELEASING HYDROGEN FROM NABH4 VIA HYDROGEL BASED CoF2 CATALYST

“…The activation energy is almost equal 50 kJ/mol as it is demanded and compatible with the literature (Seven and Sahiner, 2013 (Seven and Sahiner, 2014;Ingersoll et al, 2007). On the other hand, calculated Ea is lower than gained in the literature, 132 kJ/mol and 79 kJ/mol, when diatomite and γ-Al2O3 supported heterogeneous Co based catalyst was used for the dehydrogenation of NaBH4 (Çakanyıldırım and Gürü, 2010).…”

“…On the other hand, comparable low activation energy values were gained for hydrogen release from NaBH4 in the literature, when NaOHp(AAM)-Co composite system and super-porous p(AAc)-Co metal composites were used as catalysts (Seven and Sahiner, 2013;Seven and Sahiner , 2014).…”

“…When the released hydrogen amount compared with the results given in the literature, the produced H2 amount (No:3) via dehydrogenation of 0.095 g NaBH4 (prepared as 50 mM NaBH4 solution) was almost same with the amounts of released H2 (No:1, 2, 4) given in the literature as seen in the Table 1. (Seven and Sahiner 2014) According to the ideal hydrolysis, it is expected that 0.1 g of fully hydrolyzed NaBH4 produces mL of hydrogen gas at standard temperature and pressure. If we take into account temperature effect, produced H2 gas should be 241 mL and 245 mL at 30 °C and 35 °C be regarding ideal gas law.…”

Preparation and characterization of a novel pH-sensitive Salecan-g-poly(acrylic acid) hydrogel for controlled release of doxorubicin

“…In particular, "intelligent" hydrogels whose physicochemical properties can undergo signicant changes in response to various external stimuli, such as temperature, 1 pH, 2,3 light, 4 electric/magnetic eld, 5,6 ionic strength, etc., 7 have attracted a great deal of attention in biological, medical, pharmaceutical and environmental applications. [8][9][10][11][12][13] Among these "intelligent" hydrogels, pH-sensitive ones have been widely studied to develop controlled drug delivery systems due to large variations of pH in different tissues and cellular compartments. 14,15 For example, the pH in blood and normal tissues is stable at around 7.4, the tumor extracellular environment is more acidic (pH 6.5) and in endosomes and lysosomes, the pH values are even lower (4.0-6.0).…”

Stability and kinetic studies of MOF‐derived carbon‐confined ultrafine Co catalyst for sodium borohydride hydrolysis

“…15 To inhibit the agglomeration of nanoparticles and improve the stability, many researchers have made considerable efforts toward immobilizing Co nanoparticles on various substrates such as carbon, 16 hydroxyapatite, 17 CNT, 18 graphene oxide, 19 TiO 2 , 20 and SiO 2 21 or combining Co nanoparticles with different hydrogel materials to form hydrogel-metal composites. [22][23][24][25] The usual processes of anchoring fine particles on supports often experience high-temperature treatment, which inevitably induces the aggregation of metallic particles and thus the reduction of catalytic activity. An alternative strategy is the utilization of structure controlling templates, which can produce cobalt embedded materials with high dispersion of metal nanoparticles.…”