Thermal Studies of Nickel, Cobalt, Iron and Copper Oxides and Nitrates.

Keely, W. M.; Maynor, Harry W.

doi:10.1021/je60018a008

Cited by 70 publications

(30 citation statements)

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“…11,12 As shown in Fig. 1a-1d RuO 2 and indeed all oxide films containing RuO 2 prepared by thermal decomposition display the characteristic mud-cracked appearance associated with RuO 2 films prepared previously by others.…”

Section: Resultssupporting

confidence: 60%

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Godwin

Doyle

Lyons

2014

J. Electrochem. Soc.

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RuO 2 /NiO mixed oxide electrodes prepared by thermal decomposition were examined as potential water oxidation catalysts. Addition of just 10 mol% RuO 2 to a NiO electrode was found to decrease the oxygen evolution reaction (OER) onset potential by 20% with increasing additions having significantly diminishing returns. The OER current densities for the RuO 2 /NiO electrode were found to increase when preconditioned by application of prolonged polarization regimes with the Tafel slope also decreasing when conditioned. NiO prepared by thermal decomposition was found to behave in a similar manner to other nickel oxides prepared using different methodologies and we propose a similar OER mechanism based on the kinetic data obtained using the surfaquo group concept. A dual barrier model was used to rationalize the fractional reaction order of ca. 0.5 observed for RuO 2 .Alkaline water electrolysis has become an area of intense international research due to the need for a method to efficiently produce large amounts of molecular hydrogen which would be required for a potential hydrogen economy. Currently one of the main drawbacks limiting the widespread use of this technology is in the large anodic overpotential associated with the oxygen evolution reaction (OER). Dimensionally Stable Anodes (DSA) are one such technology which can effectively catalyze the OER thus increasing the overall efficiency of the water electrolysis reaction. DSA electrodes consist of an underlying electrochemically inert valve metal substrate such as titanium or tantalum, coated usually with an oxide or mixed oxides of platinum group metals (PGM). To date, they have been employed in many industrial processes such as the chlorine evolution reaction, 1 electrowinning of metal ores 2 and as an anode for use in industrial water electrolyzers. 3 Herein, we focus attention on the latter use in an alkaline environment. DSA electrodes based on IrO 2 /RuO 2 currently exhibit one of the lowest overpotential for the oxygen evolution reaction (OER), which is said to be the 'bottleneck' or rate determining step in a water electrolyzer cell at standard operating currents. PGM oxide mixtures such as IrO 2 /RuO 2 as studied by Lyons, 3,4 Trasatti 4-6 and others on Ti exhibit extremely low OER overpotentials (ca. 0.20-0.25 V) and display long term stability in strong alkaline conditions required for an alkaline water electrolyzer setup. However, the main drawback in fully utilizing PGM oxide based DSA electrodes is in the high cost associated with these metals, and thus, significant international research is being currently focused on finding cheaper alternatives which still display relatively low overpotentials. This paper focuses on minimizing the amount of expensive PGM oxides, RuO 2 in this case which currently costs $2.1 million/ton, required by combining them with low cost NiO, currently $14 000/ton, which displays relatively low overpotentials for the OER 7-9 but at a significantly lower cost. A range of RuO 2 /NiO compositions was studied herein and the e...

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Section: Resultssupporting

confidence: 60%

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Godwin

Doyle

Lyons

2014

J. Electrochem. Soc.

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“…The peak at $240°C may be attributed to the partial decomposition of the nickel (II) nitrate hexahydrate as a previous step to its complete decomposition into NiO. Several studies have shown that the decomposition of nickel (II) nitrate hexahydrate is a complex process since the nickel decomposes before the removal of all the water of crystallization, into intermediate compounds, the exact composition of which has not yet been established [19][20][21]. The narrow peak at around 267°C corresponds to the decomposition of this intermediate compound into…”

Section: Catalytic Graphitization Of Cellulosic Hydrocharmentioning

confidence: 99%

Graphitic carbon nanostructures from cellulose

Sevilla

Fuertes

2010

Chemical Physics Letters

144

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“…Morozov et al (13)observed two or three stages of Cu(NO 3 ) 2 Á 3H 2 O thermolysis at atmospheric pressure: melting of hydrate at 116$152 C, formation of b-Cu 2 (OH) 3 NO 3 (199$217 C), and its decomposition to CuO (263$310 C). However, Keely et al (14). stated the Cu(NO 3 ) 2 Á 3H 2 O decomposition to cupric oxide was essentially complete at 350 C and there was no evidence for the formation of an oxynitrate as had been previously reported in the literature.…”

Section: Results and Discussion Effect Of Kinds Of Copper Precursors mentioning

confidence: 83%

“…Zhu et al (15) claimed the formation of CuO phase on activated carbon subjected to heating in argon atmosphere at 180 C, and increasing the heating temperature to 350 C and 450 C led to the formation of Cu 2 O and Cu metal, respectively. The Cu(NO 3 ) 2 Á 3H 2 O decomposition to CuO was essentially complete at 350 C (14,20) and CuO was well dispersed over the AC adsorbent calcinated at 350 C. Furthermore, increasing the calcinations temperature would lead to the formation of Cu 2 O and Cu metal. Therefore, the catalyst with 2.36 wt% Cu loading and calcined at 350 C shows the biggest adsorption capacity.…”

Section: Effect Of Calcination Temperature On Cu(n)/ac Adsorbent For mentioning

confidence: 98%

Effect of Preparation Conditions on the Property Cu/AC Adsorbents for Phosphine Adsorption

Ning

et al. 2012

Separation Science and Technology

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Copper-based activated carbon adsorbents (Cu/AC) were prepared and used to investigate the effects of various copper precursors, impregnation solution concentration, and calcination temperature on phosphine (PH 3 ) adsorption removal from yellow phosphorus tail gas. N 2 adsorption isotherm and X-ray Diffraction (XRD) were used for characterizing the Cu/AC adsorbents. It can be seen that the Cu(N)/AC adsorbent prepared from the Cu(NO 3 ) 2 precursor has higher PH 3 breakthrough adsorption capacity than other three adsorbent because the surface copper status of it is mainly CuO. Fresh activated carbon requires an optimal impregnation solution concentration (0.05 mol/L) to reach this optimal PH 3 breakthrough adsorption capacity (78.62 mg/g). The result shows that the surface chemical characteristics (Cu content) of activated carbon is more important than the physical ones (specific surface or pore volume) for the PH 3 adsorption performance. When the calcination temperature is 350 C, the Cu(N)/AC adsorbent has the biggest PH 3 breakthrough adsorbed amount of 112.38 mg/g. The present study confirmed that the Cu/AC adsorbents would be one of the candidates for PH 3 adsorption removal from yellow phosphorus tail gas.

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Thermal Studies of Nickel, Cobalt, Iron and Copper Oxides and Nitrates.

Cited by 70 publications

References 2 publications

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Graphitic carbon nanostructures from cellulose

Effect of Preparation Conditions on the Property Cu/AC Adsorbents for Phosphine Adsorption

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