02286nas a2200169   4500008004100000022001400041245011100055210006900166260007100235300001600306490000800322520159100330100002101921700002401942700002401966856012601990       2012                        eng d  a1932-744700aVisible-light-induced photosplitting of water over gamma `-Fe4N and gamma `-Fe4N/alpha-Fe2O3 nanocatalysts0 aVisiblelightinduced photosplitting of water over gamma Fe4N and   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a12156-121640 v1163 a<p>The application of gamma'-Fe4N, a noble-metal-free, low-cost catalyst, in the photosplitting of neat water into stoichiometric amounts of H-2 and O-2 under visible-light irradiation is reported for the first time. The catalyst showed optical absorption and photoluminescence emission bands in the entire visible region. The photocatalytic water-splitting activity was wavelength-dependent, the quantum efficiency for H-2 evolution being ca. 1.7 and 0.7% at excitation wavelengths of 450 and 500 nm, respectively. Addition of electron donor/acceptor sacrificial reagents considerably affected the yield and stoichiometry of H-2 and O-2. At the same time, the product yield increased in a composition-dependent manner for (gamma'-Fe4N)(x) + (alpha-Fe2O3)(1-x) nanocomposites. This activity augmentation is ascribed to the better dispersion of the active component gamma'-Fe4N and also to the availability of more active surface sites at Fe4N/Fe2O3 contacts. Moreover, the proximity of the valence band potential of the component photosystems promotes the preferential transfer/entrapment of photoexcited hole carriers. We envisage that the defect/impurity-induced interband-gap energy states may play a vital role in these charge-transfer processes, leading thereby to more effective e(-)-h(+) separation and the enhanced rate of the water-splitting reaction. First-principles electronic structure analysis suggests that the extraordinary photocatalytic and optical properties of intermetallic gamma'-Fe4N may arise from the particle-size-dependent changes in electronic structure.</p>1 aDhanasekaran, P.1 aSalunke, Hemant, G.1 aGupta, Narendra, M.  uhttps://library.ncl.res.in/content/visible-light-induced-photosplitting-water-over-gamma-fe4n-and-gamma-fe4nalpha-fe2o3-0