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ca 2 fe 2 o 5 (cfo) is a potentially viable material for alternate energy applications. incorporation of nitrogen in ca 2 fe 2 o 5 (CFO-N) lattice modifies the optical and electronic properties to its advantage. Here, the electronic band structures of cfo and cfo-n were probed using Ultraviolet photoelectron spectroscopy (UPS) and UV-Visible spectroscopy. The optical bandgap of CFO reduces from 2.21 eV to 2.07 eV on post N incorporation along with a clear shift in the valence band of CFO indicating the occupation of N 2p levels over O 2p in the valence band. Similar effect is also observed in the bandgap of CFO, which is tailored upto 1.43 eV by N + ion implantation. the theoretical bandgaps of cfo and cfo-n were also determined by using the Density functional theory (Dft) calculations. the photoactivity of these CFO and CFO-N was explored by organic effluent degradation under sunlight. The feasibility of utilizing cfo and cfo-n samples for energy storage applications were also investigated through specific capacitance measurements. The specific capacitance of CFO is found to increase to 224.67 Fg −1 upon n incorporation. cfo-n is thus found to exhibit superior optical, catalytic as well as supercapacitor properties over cfo expanding the scope of brownmillerites in energy and environmental applications.Multifunctional brownmillerite Ca 2 Fe 2 O 5 is a promising material for energy and environmental applications such as fuel cells, supercapacitors, batteries, H 2 production and CO 2 capture, attributed mostly to its multifaceted property like those in catalysis and mixed ionic electronic conduction (MIEC) 1-5 . Presence of a visible region bandgap along with its catalytic activity also enables it as a photoactive material and most importantly as material for textile waste water remediation. There is a huge need for industrial waste water purification of the effluents from the textile industries before releasing it to water bodies. A lower cost and energy requirement pushes us to explore more efficient materials which can absorb a larger percentage of incident natural sunlight and make their impact felt on the environment 6-10 . Well known wide band gap semiconductors, such as TiO 2 and ZnO (bandgap > 3 eV), cannot perfectly match the broad ranges of solar radiation emphasizing the need to investigate new materials/composites with narrow bandgap 11 . Quite recently perovskite metal oxides, such as PbTiO 3 (2.75 eV), AgNbO 3 (2.86 eV), SrNbO 3 (1.9 eV), BiFeO 3 (2.1 eV), LaFeO 3 (2.4 eV), LaNiO 3 (2.42 eV) have been found to possess reasonable catalytic efficiency [12][13][14][15][16][17][18][19] . This encourages us to work with novel materials like oxygen deficient perovskites for sunlight-driven photocatalysis.To meet the above objectives, it is desirable to modify such structures with transition metal-N x active sites to enhance the charge transport features and hence the catalytic activity towards remediation of industrial wastewater 20,21 . Recently, Nitrogen-doped layered perovskite K 2 La 2 Ti 3 O 10 was sh...

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The oxygen storage capacity, oxygen exchange kinetics, structure and thermodynamic stability were studied for hexagonal Y0.7Tb0.3MnO3+δ in oxygen and air to assess its applicability for oxygen separation from air by a temperature-swing adsorption process.