Effect of samarium and vanadium co-doping on structure, ferroelectric and photocatalytic properties of bismuth titanate

Abstract

We performed a systematic analysis of the structure, ferroelectric and photocatalytic activities of Sm and V codoped Bi 4 Ti 3 O 12 (SBVT) ceramics. The formation of 3-layered Aurivillius structure and chemically induced strain of SBVT were analyzed by SEM and HRTEM studies. From the results of structural refinements, temperature dependent XRD and Raman spectra we found that SBVT has a distorted orthorhombic structure and transforms to tetragonal in the temperature range of 475-600 C. Raman modes of Bi sites experience the phase transition earlier compared to torsional bending modes of BO 6 octahedra. From the results of polarization and piezoelectric strain measurements, we found that SBVT exhibits superior ferroelectric characteristics as well as improved S 33 (0.02 Â 10 À3 ) compared to other rare-earth doped Bi 4 Ti 3 O 12 materials reported in the literature. SBVT exhibited fatigue endurance up to 10 8 switching cycles. Such a behavior is attributed to the structural distortions due to the smaller ionic radius of Sm 3+ and reduced oxygen vacancies. Local piezoresponse measurements demonstrated imprint characteristics of ferroelectric domains. Furthermore, we assessed the photocatalytic (PC) activity of SBVTfor the first timein the gassolid phase, monitoring the degradation of nitrogen oxides (i.e. NO + NO 2 ). Results demonstrated that SBVT was photocatalytically active in the solar spectrum, being able to degrade NO x at ppb level concentration, and exhibited a very stable PC activity (five consecutive PC runs), proving itself suitable for reuse.rsc.li/rsc-advances 9680 | RSC Adv., 2017, 7, 9680-9692This journal is

Structure-property relationships in the lanthanide-substituted PbBi2Nb2O9 Aurivillius phase synthesized by the molten salt method

“…As compared to pristine PBNO, the substitution of La 3+ results in a significant increase of the b and c lattice parameters, whereas the substitution of Nd 3+ significantly decreases the a and c lattice parameters. These changes imply a decrease in the degree of orthorhombic distortion in the ab-plane with Ln 3+ substitution, by which the a and b lattice parameters approach each other [27,28]. The decreased degree of distortion can also be expressed in terms of the orthorhombicity ratio ((a-b)/(a+b)) in Table 2.…”

Effects of cerium on structures and electrical properties of (Nb, Ta) modified Bi4Ti3O12 piezoelectric ceramics

“…The photoemission Ti 2p spectrum of BCTNT0 and BCTNT3 ceramics is presented in Figure 3E. The asymmetric peak was linked to the partial overlapping of Ti 2p1/2, Ti 2p3/2, and Bi 4d3/2 28 . The Ti 2p3/2 peaks of BCTNT0 and BCTNT3 ceramics were observed at 457.79 eV and 457.87 eV, respectively.…”

The Effects of Li+ Doping on Structure and Upconversion Luminescent Properties for Bi3.46Ho0.04Yb0.5Ti3O12: xLi Phosphors

“…The VC values first increased and then decreased while the DC increased monotonously with the increase in Li + content in the BHYTO: xLi phosphors, and the DC values were calculated to be about 34.59 nm, 37.36 nm, 38.33 nm, 45.74 nm, and 48.17 nm for the BHYTO: xLi samples with x equal to 0, 0.02, 0.05, 0.1, and 0.15, respectively, according to famous Scherrer formula. For an Aurivillius structured material, the lattice distortion and strain are usually expressed by the ratios of crystal parameters, that is, b/a and c/a, respectively, and the ratios increased with the increase in crystal distortion and strain increases [23]. Compared to Li + undoped BHYTO, the degree of crystal distortion and strain were relieved significantly in Li + doped BHYTO: xLi phosphors, because the ratio of b/a and c/a decreases gradually.…”

“…EDS results show that the samples were composed of Bi, Yb, Ho, Ti, and O elements and no impurity element detected in the samples. The detected C element came from a graphite conductive adhesive tape For an Aurivillius structured material, the lattice distortion and strain are usually expressed by the ratios of crystal parameters, that is, b/a and c/a, respectively, and the ratios increased with the increase in crystal distortion and strain increases [23]. Compared to Li + undoped BHYTO, the degree of crystal distortion and strain were relieved significantly in Li + doped BHYTO: xLi phosphors, because the ratio of b/a and c/a decreases gradually.…”