CuO Fe2O3 Research Articles

Electrochemical Properties of Yolk-Shell-Structured CuO-Fe2O3Powders with Various Cu/Fe Molar Ratios Prepared by One-Pot Spray Pyrolysis

Several yolk-shell-structured CuO-Fe2 O3 powders with various Cu/Fe molar ratios have been successfully prepared under equivalent reaction conditions using a one-pot spray pyrolysis process. The Cu and Fe components are uniformly distributed throughout the powders, irrespective of composition. The Brunauer-Emmett-Teller surface areas of the yolk-shell CuO-Fe2 O3 systems increased from 5 to 16 m(2) g(-1) if the Cu/Fe molar ratios are decreased from 3:1 to 1:3. The initial discharge and charge capacities of the yolk-shell CuO-Fe2 O3 system (Cu/Fe=1:2), showing maximum values at a constant current density of 1000 mA g(-1) , are 1436 and 1012 mA h g(-1) , respectively. After 130 cycles, the discharge capacities of the yolk-shell CuO-Fe2 O3 powders with Cu/Fe molar ratios of 1:3, 1:2, 1:1, 2:1, and 3:1 are 1159, 1151, 755, 655, and 651 mA h g(-1) , respectively. The discharge capacities of the yolk-shell and dense powder samples after 50 cycles, when subjected to a series of current density increases from 500 to 5000 mA g(-1) , are 735 and 495 mA h g(-1) , respectively.

Thermal Removal of Mercury in Spent Powdered Activated Carbon from TOXECON Process

This research developed and demonstrated a technology to liberate Hg adsorbed onto powdered activated carbon (PAC) by the TOXECON process using pilot-scale high temperature air slide (HTAS) and bench-scale thermogravimetric analyzer (TGA). The HTAS removed 65, 83, and 92% of Hg captured with PAC when ran at 900°F , 1,000°F , and 1,200°F , respectively, while the TGA removed 46 and 100% of Hg at 800°F and 900°F , respectively. However, addition of CuO–Fe2 O3 mixture and CuCl catalysts enhanced Hg removal and PAC regeneration at lower temperatures. CuO–Fe2 O3 mixture performed better than CuCl in PAC regeneration. Scanning electron microscopy images and energy dispersive X-ray analysis show no change in PAC particle aggregation or chemical composition. Thermally treated sorbents had higher surface area and pore volume than the untreated samples indicating regeneration. The optimum temperature for PAC regeneration in the HTAS was 1,000°F . At this temperature, the regenerated sorbent had sufficient adsorptio...

Thermal solid–solid interaction and physicochemical properties of CuO–Fe2O3 system

A series of single and mixed oxides of CuO–Fe2O3 was prepared by thermal treatment of pure and mixed copper and ferric nitrate solids at 350–1000°C. The thermal behaviour of the single and binary salts has been studied using the thermal analysis (TG-DTG) technique. The thermal products were characterised using the X-ray diffraction analysis. The results revealed that copper and ferric nitrates decomposed to CuO and Fe2O3 at about 400°C, respectively, in the Cu–Fe mixtures. The presence of ferric oxide in the mixture prevents the reduction process of CuO to Cu2O. Crystalline copper ferrite phase was detected at 750 and 1000°C as a result of solid–solid interaction between CuO and Fe2O3. The presence of excess of CuO in the mixture stimulates the formation of well crystalline copper ferrite phase while excess of Fe2O3 hinders the previous process. The catalytic activity of the obtained pure and mixed oxides was measured using the decomposition of hydrogen peroxide at 30–50°C. It was found that the mixed oxide solids have catalytic activity higher than single oxides preheated at 350 and 550°C. The rise in precalcination temperature to 750 and 1000°C brought about a drastic decrease in the activity of mixed solids because of formation of copper ferrite phase and/or sintering process.