Partial nitrogen loss in SrTaO2N and LaTiO2N oxynitride perovskites

Additive sintering and post-ammonolysis of dielectric BaTaO2N oxynitride perovskite

“…2. SrTaO 2 N began to release nitrogen in about 15% at 950 • C [12]. The lower thermal stability of BaTaO 2 N may be related to the lower lattice enthalpy of the barium compounds than that of the strontium homologues [13][14][15].…”

“…The color change was assumed to be induced by the reduction of Ta 5+ in BaTaO 2 N because of its partial loss of nitrogen, as is observed in SrTaO 2 N [2, 3,12]. The ceramic was electrically semiconducting and not insulating to show dielectric property.…”

“…The post-annealed SrTaO 2 N ceramics with RD = 83.3% had a relatively high relative permittivity of 450 with a low dielectric loss of less than 0.1 at 10 2 Hz, almost independent of frequency and temperature [2]. The thermal behavior of SrTaO 2 N powder was studied in a nonoxidative atmosphere in relation to its sintering conditions [12]. Thermal releasing of its nitrogen started in a helium atmosphere at 950 • C, but the perovskite structure was maintained even after approximately 30 at% loss of nitrogen.…”

Polar nano-region structure in the oxynitride perovskite LaTiO2N

“…22 Clarke et al, Logvinovich et al, and Chen et al have claimed that this compound crystallizes in a triclinic, I% 1 structure with partial O/N trans-order on the TiO 4 N 2 octahedron. 2,23,24 In contrast, Yashima et al have reported crystallization in the orthorhombic Imma space group with O/N site disorder, where O and N atoms occupy random anion sites. 14 The Imma type perovskite can be described by the a 0 b À b À Glazer tilt system 25,26 with a O2 Â 2 Â O2 unit cell (Fig.…”

Defect Engineering for Photocatalysis: From Ternary to Perovskite Oxynitrides

“…Consequently, a higher overpotential was generated by these adsorbed species. These results provide a mechanistic explanation for the experimentally observed drop in OER activity with N‐loss in SrTaO 2 N photoanodes and are consistent with independent DFT results predicting a preference for O 2− anions to steal adjacent N 3− vacancy sites as a function of charge in bulk TaON . Recently Seo et al .…”