| Co NPs in P(vi) microgels (homogeneous hybrid microgel) |
Generation of hydrogen by hydrolysis of NaBH4
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Zeta potential, FTIR, DLS, TGA, AAS, UV-Vis |
Zeta-potential and DLS used to find the particle size, hydrodynamic radius, and surface charge. The size of P(vi)-por, P(vi), and P(vi)–Si microgels were 764 nm, 304 nm, and 530 nm, respectively, according to DLS technique. Hdr of P(vi)-por was greater than P(vi)–Si due to generation of pores after the removal of Si and more water intake. The zeta-potential value of P(vi)-por, P(vi), and P(vi)–Si microgels were −21.99 mV, 1.20 mV, and −19.86 mV, respectively. A more negative value of P(vi)-por microgel indicates that some amount of Si is present in the microgel in porous form. Different functionalities from microgel characterized with the help of FTIR. P(vi) microgels lost 90% weight, and weight-loss of P(vi)-por and P(vi)–Si were almost similar (31.3% wt and 34.4% wt, respectively), which was indicated by the TGA technique. The contents of Co nanoparticles in P(vi), P(vi)-por, and P(vi)–Si microgels were 7.71, 8.56, and 8.46, respectively, calculated with AAS |
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| Co NPs loaded in P(4VP) cryogel (homogeneous hybrid microgel) |
Hydrogen generation by hydrolysis of NaBH4 and NH3BH3
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FTIR, TGA, AAS |
FTIR technique was used to identify the presence of different functional groups present in microgels and hybrid microgels. The content of Co nanoparticles in Co NPs loaded P(4VP) microgel was 11.5 wt%, which was found with the help of TGA in the first loading. This amount was increased by increasing the loading steps. This amount was 25.4 wt% in the third and 33 wt% in the fifth loading. The contents of Co NPs according to the AAS technique were 20.49, 49.97, 85.4, 94.5, and 97.3 mg g−1 in 1st, 2nd, 3rd, 4th, and 5th loading. In continuously loading the metal, the metal content increases and hence the active sites for catalytic performance |
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| Metal NPs in P(NipaM)/P(HemA) (homogeneous hybrid microgel) |
Can be used for catalysis |
1H NMR, TEM, FTIR, EDS, SEM, UV-Vis |
The structure of the microgel has been characterized by 1H NMR. Functionalities of microgel and hybrid microgel identified with FTIR. Size of the microgel identified with SEM and metal nanoparticles with TEM techniques. The diameter of microgels was from 150 to 1000 μm and metal nanoparticles from 5 to 6 nm for Au, 20–25 for Ag and 30 for Co nanoparticles loading in microgels |
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| Co NPs loaded into poly(ethylene imine) P(EI) (homogeneous hybrid microgel) |
Generation of H2 by hydrolysis of NaBH4 and catalytic reduction of 4-nitrophenol |
SEM, FTIR, TGA, DLS, zeta potential |
SEM technique was used to determine the spherical morphology and size of the microgel in the swollen state. The particle size of microgels was in the range of 10 nm to 10 μm. Different functionalities of polymer particles and microgels were confirmed by FTIR. Property of thermal stability of polymer particle and microgels characterized with TGA technique. TGA indicated that the stability of the microgel is slightly more than the hybrid. The difference of wt% between polymer and microgels is 17.44%, which is the cross-linking density value. The size in diameter of microgel, obtained by zeta potential, without and with filtration were 1175 and 558 nm, respectively |
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| Co NPs onto porous P(4VP) microgel (porous hybrid microgel) |
Generation of H2 by hydrolysis of NaBH4
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DLS, zeta potential, FTIR, AAS, BET |
FTIR technique has been used to identify different functionalities and incorporation of nanoparticles in the porous surface due to the shifting of stretching frequency. Particle sizes were 333, 398, and 478 nm for P(4VP), P(4VP)-silica, and P(4VP)-porous microgels, respectively, which were obtained by the DLS technique. Surface areas of these microgels obtained with the help of the BET technique were 43.78, 24.02, and 42.26 m2 g−1 for P(4VP)-silica, P(4VP), and P(4VP)-porous, respectively. TGA has been used to check the stability of microgels. P(4VP) lost 15.5% more amount as compared to P(4VP)-silica |
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