Lead-free ferroelectric Na1−xSrx (Sn0.25Ti0.75) xNb1−xO3 system (0.1 ≤ x ≤ 0.4) XRD, dielectric, and Raman properties

Design of High-Performance Iron–Niobium Composite Oxide Catalysts for NH3-SCR: Insights into the Interaction between Fe and Nb

“…Peaks at 209 (A 1g ), 270 (E g ), 383 (E g ), 482 (A 1g ), and 582 (E g ) cm –1 assignable to α-Fe 2 O 3 were clearly observed for FeO x and FeO x -C, − in agreement with the results of XRD. The peaks of α-Fe 2 O 3 were also observed for FeNb 0.4 O x with weaker intensity compared to those for FeO x and FeO x -C. Meanwhile, peaks located at 130 and 800 cm –1 related to the NbO 6 octahedral framework appeared for FeNb 0.4 O x . , This was ascribed to unsaturated Nb species with dangling bonds, which could provide Lewis acid sites for NH 3 adsorption . As for FeNb 0.4 O x -C, a slight peak shift from 270 to 283 cm –1 as well as a small emerging peak at 342 cm –1 was possibly due to the formation of γ-Fe 2 O 3 . ,− It was also observed that peaks of NbO 6 in the pattern for FeNb 0.4 O x -C were much stronger than those for FeNb 0.4 O x , which may give rise to more Lewis acid sites on the surface of the catalyst.…”

Structure properties and dielectric relaxation of Ca0.1Na0.9Ti0.1Nb0.9O3 ceramic

“…The peaks assigned to the Nb-O phonon Raman spectrum are identied at 276 cm À1 for NaNbO 3 . [43][44][45] . On the other hand, in the CNNT, they are observed at 259 cm À1 (Fig.…”

Studies on structural, dielectric and optical properties of (Ba0.95Ca0.05)1−x(Ti0.8Sn0.2)1−xNaxNbxO3 lead-free ceramics

“… 41 These results are in good agreement with those reported in the prototype relaxor PbMg 1/3 Nb 2/3 O 3 , 1.6 (ref. 42 ) and Na 1− x Sr x (Sn 0.25 Ti 0.75 ) x Nb 1− x O 3 lead-free 43 ceramic.…”