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Nanostructured TiO 2 thin films were prepared by pulsed laser deposition (PLD) on indium doped tin oxide (ITO) substrates. Results from X-ray photoelectron spectroscopy (XPS) show that Ti 2p core level peaks shift toward the lower binding energy with decrease in the buffer gas pressure (O 2 :Ar = 1:1). This suggests that oxygen vacancies are created under insufficient oxygen conditions. Anatase to rutile ratio is also found to be system pressure dependent. Under deposition pressure of 750 mTorr only anatase phase was observed even at 1073 K substrate temperature which is much higher that the bulk anatase to rutile phase transformation temperature. The deposited TiO 2 thin films were fabricated as photoanodes for photoelectrochemical (PEC) studies. PEC measurements on TiO 2 photoanodes show that the flatband potential (V fb ) increases by 0.088 eV on absolute vacuum energy scale (AVS) with decrease in the deposition pressure, from 750 to 250 mTorr at 873K. The highest incident photon to current conversion efficiency [IPCE(λ)] of 2.5 to 6 % was obtained from the thin films prepared at substrate temperature of 873K.Combining the results from XPS and PEC studies, we conclude that the deposition pressure affects the concentration of the oxygen vacancies which changes the electronic structure of the TiO 2 . With reference to photoelectrochemical catalytic performance, our results suggest that it is possible to adjust the Fermi energy level and structure of TiO 2 thin

Hydrogen is among several energy sources that will be needed to replace the quickly diminishing fossil fuels. Free hydrogen is not available naturally on earth and the current processes require a fossil fuel, methane, to generate hydrogen. Electrochemical splitting of water on titania proposed by Fujishima suffers from low efficiency. The efficiency could be enhanced if full sun spectrum can be utilized. Using pulsed laser deposition technique we synthesized nitrogen doped titanium dioxide (TiO2−xNx) thin films with improved visible light sensitivity. The photoactivity was found to be N concentration dependent. Hydrogen evolution was observed under visible light irradiation (wavelength>390 nm) without the presence of any organic electron donor.

High hydrogen-content aliphatic polymers have been identified as good for shielding against galactic cosmic radiation. However, their utility in structural elements is limited to modest temperatures where desirable mechanical properties are maintained. On the other hand, aromatic polymers generally have a broader range of operating temperatures but are less effective as radiation shields. The radiation shielding properties of aromatic polymers is enhanced by the incorporation of hydrogen-rich aliphatic groups appended to aromatic units in the macromolecular structure. It is envisioned that functionally graded polymer structures using aliphatic/aromatic hybrids can be used to meet the requirements of the service environment with beneficial radiation shielding properties in future space structural applications. This paper discusses the syntheses of such hybrid polymers.