Nickel Hydr oxides

3 NiO from Fisher Properties BET specific surface area 4.6 inVg, structure pure bunsenite (XRD) [1728], 

4 NiO from joung Dong Properties SEM image available, particle diameter 300-600 nm [1729], 

PZC/IEP of NiO from Sigma Aldrich, 99.999% Pure Electrolyte T Method Instrument pH Reference 

2 Purity not Specified Properties BET specific surface area 

2 Calcination for3 h at400°C in Oxygen Evaporation of Ni(NO3)2 solution in 2-propanol, then calcination at 400°C for 3 h in a stream of oxygen. 

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The discharge of organic pollutants into lakes or declines in the concentrations of copper, zinc, and other heavy metal toxins may promote the growth of phytoplankton (e.g. algal blooms ). Greater biological activity may then increase anoxic conditions in lake bottoms, which stimulate the reductive dissolution of (oxy)(hydr)oxides and increase the mobilization of arsenic. In particular, Martin and Pedersen (2002) concluded that reduced discharges of copper, zinc, and nickel to Balmer Lake, Ontario, Canada, increased phytoplankton production and arsenic mobility in the lake. 

Hydrosilicate formation is also in evidence in the Cu(II)-Si02 system. Via precipitation from a homogeneous solution one can obtain highly dispersed copper oxide on silica (cf. above, Fig. 9.10, where it should be noted that the Cu case is more complicated than the Mn one in that intermediate precipitation of basic salts can occur). Reaction to copper hydrosilicate is evident from temperature-programmed reduction. As shown in Fig. 9.12 the freshly dried catalyst exhibits reduction in two peaks, one due to Cu(II) (hydr)oxide and the other, at higher temperature, to Cu(II) hydrosilicate. Reoxidation of the metallic copper particles leads to Cu(II) oxide, and subsequent reduction proceeds therefore in one step. The water resulting from the reduction of the oxide does not produce significant amounts of copper hydrosilicate, in contrast to what usually happens in the case of nickel. 

Prominent among the electroactive metal (hydr)oxides studied is nickel hydroxide. The EQCM has proved to be extremely useful in exploring aspects of the electrochemically driven precipitation of Ni(OH)2 and its subsequent redox chemistry. Figure 11 [72] shows EQCM data for Ni(OH)2 deposition from Ni(N03)2... 

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