PbO 2 is one material that has recently emerged as potential transparent conducting oxide for applications in the modern opto-electronic industry. In this work the electronic structure of the α-PbO 2 polymorph has been investigated, aiming to contribute to the understanding of its high levels of conductivity. DFT calculations using B3LYP hybrid density functional and considering long range interactions among the atoms have been performed. A direct band gap of 0.90 eV has been found, compatible with high conductivity values. Although the stoichiometric material is somewhat transparent, the band structure indicates that appropriated modifications in the material Fermi level can be performed in order to decrease the absorption of light. Charge distribution plus overlap population analysis show that the material is predominantly ionic. The charge distribution throughout the material is strongly dependent on the crystal direction. Results suggest that α-PbO 2 can be potentially more interesting for opto-electronic purposes than the β polymorph.

In many applications, such as fuel storage tanks and fuel lines, galvanized steel is used as a construction material which comes into contact with biodiesel. Considering that biodiesel is more corrosive than petroleum diesel, studies that aim to increase the corrosion resistance of galvanized steel in this environment are required. The present work investigates how the chemical conversion treatment in the oxalic acid solution affects the corrosion resistance of galvanized steel in soybean biodiesel (B100) in the absence and presence of the natural additives the extract the turmeric, clove, ginger, stone breaker, and rosemary. The results obtained indicate that the conversion treatment reduces the corrosion rate of the zinc coating in soybean biodiesel in the absence and presence of additives, and in this condition the effect of the conversion treatment depends on the additive used.