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Dinitrogen adsorption on overexchanged Cu-ZSM-5 is examined at 302 K by diffuse reflectance infrared spectroscopy, N2-adsorption isotherms and tempertaure-programmed N2 desorption. The introduction of controlled amounts of impurities, together with the utilization of N(super 15)(sub 2) and CO(super 13) indicate that this band is instead related to hydrated Cu(*I)-CO species formed by accumulation on the sample of traces of H2O in the N2 flow.

A new nanostructured α-Fe2O3 photoelectrode synthesized through plasma-enhanced chemical vapor deposition (PE-CVD) is presented. The α-Fe2O3 films consist of nanoplatelets with (001) crystallographic planes strongly oriented perpendicular to the conductive glass surface. This hematite morphology was never obtained before and is strictly linked to the method being used for its production. Structural, electronic, and photocurrent measurements are employed to disclose the nanoscale features of the photoanodes and their relationships with the generated photocurrent. α-Fe2O3 films have a hierarchical morphology consisting of nanobranches (width ∼10 nm, length ∼50 nm) that self-organize in plume-like nanoplatelets (350-700 nm in length). The amount of precursor used in the PE-CVD process mainly affects the nanoplatelets dimension, the platelets density, the roughness, and the photoelectrochemical (PEC) activity. The highest photocurrent (j = 1.39 mA/cm(2) at 1.55 VRHE) is shown by the photoanodes with the best balance between the platelets density and roughness. The so obtained hematite hierarchical morphology assures good photocurrent performance and appears to be an ideal platform for the construction of customized multilayer architecture for PEC water splitting.