Nickel oxide nanoparticles

A. Salimi, E. Sharifi, A. Noorbakhsh, and S. Soltanian. Direct voltammetry and electrocatalytic properties of haemoglobin immobilized on a glassy carbon electrode modified with nickel oxide nanoparticles. Electrochem. Commun. 8, 1499-1508 (2005). 

Tong, X., et ah, Enhanced catalytic activity for methanol electro-oxidation of uniformly dispersed nickel oxide nanoparticles - carbon nanotube hybrid materials. Small, 2012. 

Figure 1. SEM images of different electrodeposited metal oxide nanoparticles Ti02 nanotube arrays grown on Ti substrate(a) cobalt oxide nanoparticles onto glassy carbon electrode (b) nickel oxide nanoparticles(c) and zinc oxide nanoparticles Reproduced from references [ 138],[ 102],[ 137] and [135] with permission from Elsevier.

Figure 28. CVs of GOx /NiOx modified GC electrode at various scan rate in pH 7 PBS, from inner to outer, 10, 20, 30, 40, 50, 60, 70, 80, 90 and lOOmVs 1. Reprinted from Biosensors and Bioelectronics, 22, ASalimi, E. Sharifi, A. NoorBakhash, S. Soltanian, Immobilization of glucose oxidase on electrodeposited nickel oxide nanoparticles Direct electron transfer and electrocatalytic activity,3148,Copy eight (2007), with permission from Elsevier.

S. Soltanian, Immobilization of glucose oxidase on electrodeposited nickel oxide nanoparticles Direct electron transfer and electrocatalytic activity,3151, Copyeight (2007), with permission from Elsevier. 

Due to high biocompability of NiOx nanoparticles, we investigate the direct electron transfer processes of immobilized hemoglobin and catalase onto glassy carbon electrodes modified with nickel oxide nanosize materials [255,256],... 

Figure 32 shows the amperometric response of the biosensor in the presence of different hydrogen peroxide concentration. As shown a well defined response was observed after hydrogen peroxide addition. The values of KM, 0.96 mM for hemoglobin and 1.37 mM for catalase indicates the immobilized biomolecules into nickel oxide nanoparticles retained their native activity. 

Fig. 6. TEM image of the catalyst ex nitrate. Some small nickel oxide nanoparticles confined inside the mesopores can be seen.

These assumptions were corroborated by transmission electron microscopy, as can be seen in Figures 5 - 7. The catalyst ex nitrate displays very large nickel oxide particles (Fig. 5) as well as nanoparticles that are confined inside the mesopores of the support (Fig. 6). For the catalyst ex citrate only very small nanoparticles have been observed, which are situated predominantly inside the mesopores of the support material (Fig. 7). 

When a chelated nickel citrate precursor is used fi)r catalyst preparation strikingly different results are obtained. Only very small nickel oxide nanoparticles can be observed after calcination, which are situated inside the mesopores of the support material. As a... 

Instead of infiltration with neat metal nanoparticles, the interstitial voids of the template opal can also be filled wifh a mefal precursor. The impregnation of the preformed colloidal crystals with the metal precursor, followed by transformation of the precursor to the neat metal and removal of the template, results in metallic inverse opals. For example, nickel oxalate was precipitated in a PS opal and converted into a NiO macroporous network by calcination of the metal salt and combustion of the polymer. In a subsequent step, the nickel oxide was reduced to neat Ni in a hydrogen atmosphere to yield a macroporous metal network [82]. It was further suggested by the authors that by the same technique other metal networks (e.g.. Mg, Mn, Fe, Zn from their oxides and Ca, Sr, Ba etc. from their carbonates) should be accessible. 

The morphology and size of particles prepared by the LPSP process are different from those produced by CSP using either an ultrasonic nebulizer or a two-fluid nozzle as atomizers under an atmospheric environment. For example, nickel oxide (NiO) nanoparticles can be formed via the LPSP route whereas, only submicronsized NiO particles are produced by ultrasonic spray pyrolysis [9]. It is evident that the nanoparticle formation mechanism in the LPSP process is different from that in the CSP process. The calculated particle size based on the ODOP principle is much larger than 100 nm, indicating that the nanoparticles are formed based on one-droplet-to-multiple-particles (ODMP). The reason can be attributed to the difference in operating pressures and aerosol formation mechanisms between the two types of aerosol generators. 

W.-N. Wang, Y. Itoh, I. W. Lenggoro, K. Okuyama Nickel and nickel oxide nanoparticles prepared from nickel nitrate hexahydrate by a low pressure spray pyrolysis, Mat. Sci. Eng. B. Ill (1), 69-76 (2004). 

Figure 17.7a shows a linear increase in nanopailicle uptake with the surfactant concentration for iron, copper, and nickel oxides. Comparison between Figures 17.3 and 17.7a reveals that the trend in nanoparticle uptake is independent of whether the surfactant is reactive or nonreactive. The increase in nanoparticle uptake was coupled with an increase in the particle size. Again, the same trend was reported for the reactive surfactant case. The inCTease in particle size is attiibnted to the higher... 

FIGURE 17.7 (a) Variation of nanoparticle uptake (open symbols) and mean particle diameter (solid symbols) upon increasing AOT concentration, (b) variation of surface area per liter (open symbols), and surface area per gram (solid symbols) upon increasing AOT concentration. (A,A) nickel oxide [31], (O, ) cupper oxide [22], and ( , ) iron oxide [21]. 

Figure 17.8b shows a decrease in the surface area per gram of nickel and iron oxide nanoparticles upon increasing R, whereas a slight increase was observed for copper oxide nanoparticle, despite the increase in the mean particle size. It seans that the mean particle size of copper oxide did not represent particle size distribution to a good extent. The figure shows au iuCTease in the surface area per liter of iron and copper oxide, only because R was limited to the portion belonging to the increase in iron and copper oxide uptake. For nickel oxide, on the other hand, a sharp decrease in surface area per liter for / > 3 resulted from the sharp decrease in nanoparticle uptake at these values of R. 

Nassar, N.N. and Husein, M.M. 2008. Maximizing the Uptake of Nickel Oxide Nanoparticles in AOT (w/o) Microemulsions. In Recent Trends in Surface and Colloid science Paul, P.K., Ed., Special Issue, World Scientific Publishing Co. Pvt. Ltd., Singapore. (In Press). 

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