Structural and morphological properties of hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All the microstructures were synthesized at a very low temperature of 70 °C with a reduced reaction time of 3 h. An increase in the pH from 0.8 to 2.1 decreased the particle sizes from 3 µm to 200 nm and an increase in the aging time from zero, three, and seven days resulted in semispherical, spherical, and euhedral jarosite structures, respectively. The Rietveld analysis also confirmed that the amount of hydronium substitution by potassium in the cationic site increased with an increase in pH. The percentages of hydronium jarosite (JH)/potassium jarosite (JK) for pH values of 0.8, 1.1, and 2.1 were 77.72/22.29%, 82.44/17.56%, and 89.98/10.02%, respectively. Microstructures obtained in this work were tested as alternative anode materials and the voltage measured using these electrodes made with hydronium-potassium jarosite microstructures and graphite ranged from 0.89 to 1.36 V. The results obtained in this work show that with reduced particle size and euhedral morphology obtained, modified jarosite microstructures can be used as anode materials for improving the lifetime of lithium-ion batteries.

One dimensional (1-D) and three dimensional (3-D) ZnO were growth by a hydrothermal method. ZnO 1-D was employed as a support for silver nanoparticles in order to design a new catalyst and used on the steam reforming of methanol (SRM) reaction for H2 production. The catalytic activity of the Ag/ZnO sample with low content of Ag showed better performance on the SRM reaction than on high silver loading catalyst. So, the sample with small Ag particle size showed best performance in methanol conversion than catalyst with big Ag particle size, this finding could be attributed to the high ZnO/Ag ratio. According to results of SEM and TEM techniques the catalytic activity: methanol conversion, H2 and low CO production observed on the Ag/ZnO 1-D catalyst occurs in the edge sites rather than the rim sites. The role of Ag is to accept the hydrogen to be released to the gas phase. In addition, the 1.5Ag/ZnO 1-D catalyst showed good stability during the reaction.

No abstract

No abstract

No abstract