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Recovery of vanadium oxide from steelmaking slag is of great interest for Swedish steel producers and the technique for assessing the oxidation state of vanadium is crucial in the optimization of vanadium recovery. There is a large spread in the reported values of published V2p 3/2 binding energy values for various oxidation states of vanadium. Therefore, an extensive analysis of vanadium oxide standards was performed aimed at obtaining reliable data and improved methods for the preparation of representative oxide standards. Powdered oxide standards of V 2 O 5 , VO 2 , V 2 O 3 , and VO, with purity better than 99%, were chosen. In their as-received state, all of the standards are covered by a thin layer of vanadium pentoxide that does not allow accurate evaluation of X-ray photoelectron spectroscopy spectra for vanadium oxides at lower oxidation states. Therefore, different methods for obtaining a representative surface for vanadium oxide standards were tested. The experimental results show high sensitivity of vanadium oxide standards to argon ion etching. Hence, a method to obtain a representative surface of standards by special heat treatment is proposed. Such approach was developed using a preparation chamber (furnace) attached to an X-ray photoelectron spectroscopy instrument. The annealing was performed in a vacuum at defined temperatures from 400 to 900 C for 4-24 h; the annealing parameters were selected based on thermodynamic equilibrium data for vanadium oxides. Experimental fitting parameters (peak position E and full width of half maximum of the peak) for vanadium V2p 3/2 and oxygen O1s peaks are thus obtained for stoichiometric vanadium oxides.

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Selective band gap manipulation of graphene oxide by its reduction with mild reagents, Carbon (2015), doi: http://dx. ABSTRACTGraphene oxide (GO) can be used as an electron acceptor for polymeric solar cells but still band gap matching for electron donor and acceptor demands more study. The generation of the exciton in such materials is intimately related to the optical band gap. However, exciton dissociation is related to transport band gap that controls the device performance, particularly the open circuit voltage and short circuit current. Therefore, the modulation of the optical gap is useful because it results into tuning of the transport gap. The interest of the present work is to study the reduction of graphene oxide (GO) at room temperature, using environmental friendly reagents like glucose, fructose and ascorbic acid for the modulation of a band gap. It has been found that glucose and fructose function effectively only in presence of NH 4 OH. Although ascorbic acid can reduce GO alone, NH 4 OH speeds up the reaction. The optical band gap of GO can be reduced and tuned effectively from 2.7eV to 1.15eV.

a b s t r a c tThe effect of temperature on the NaCl-induced atmospheric corrosion of the Mg-Al alloy AM50 has been investigated in the laboratory. The corroded samples were analyzed gravimetrically and by SEM, EDX, XRD, and FTIR. The atmospheric corrosion of 99.97% Mg was also studied for reference. While the NaCl-induced atmospheric corrosion of AM50 is strongly reduced with decreasing temperature, 99.97% Mg does not exhibit such a trend. The temperature dependence of the atmospheric corrosion of alloy AM50 is attributed to the aluminum content in the alloy. Several crystalline magnesium hydroxy carbonates formed at 4 and 22°C but were absent at À4°C.