Simple Low Temperature Technique to Synthesize Sillenite Bismuth Ferrite with Promising Photocatalytic Performance

Abstract

Sillenite-type members of the bismuth ferrite family have demonstrated outstanding potential as novel photocatalysts in environmental remediation such as organic pollutant degradation. This investigation has developed a low temperature one-step hydrothermal technique to fabricate sillenite bismuth ferrite Bi 25 FeO 40 (S-BFO) via co-substitution of 10% Gd and 10% Cr in Bi and Fe sites of BiFeO 3 , respectively, by tuning hydrothermal reaction temperatures. Rietveld refined X-ray diffraction patterns of the as-synthesized powder materials revealed the formation of S-BFO at a reaction temperature of 120–160 °C. A further increase in the reaction temperature destroyed the desired sillenite structure. With the increase in the reaction temperature from 120 to 160 °C, the morphology of S-BFO gradually changed from irregular shape to spherical powder nanomaterials. The high-resolution TEM imaging demonstrated the polycrystalline nature of the S-BFO(160) nanopowders synthesized at 160 °C. The as-synthesized samples exhibited considerably high absorbance in the visible region of the solar spectrum, with the lowest band gap of 1.76 eV for the sample S-BFO(160). Interestingly, S-BFO(160) exhibited the highest photocatalytic performance under solar irradiation, toward the degradation of rhodamine B and methylene blue dyes owing to homogeneous phase distribution, regular powder-like morphology, lowest band gap, and quenching of electron–hole pair recombination. The photodegradation of a colorless organic pollutant (ciprofloxacin) was also examined to ensure that the degradation is photocatalytic and not dye-sensitized. In summary, Gd and Cr co-doping have proven to be a compelling energy-saving and low-cost approach for the formulation of sillenite-phase bismuth ferrite with promising photocatalytic activity.

Tuning the morphology, stability and optical properties of CsSnBr3 nanocrystals through bismuth doping for visible-light-driven applications

“…Before including any photocatalyst in the dye solution, the self- decomposition rate of RhB was determined under identical conditions and only 4% RhB degradation was recorded aer 240 min, which is in good agreement with a previous study. 66 From the absorbance curve depicted in Fig. 9(a) and (b), it can be observed that the peak intensity of the spectra was reduced with respect to time following a hypsochromic shi, which indicates the deterioration of RhB solution under the UVvis spectrum due to the inclusion of CSB and CSB ′ B samples, respectively.…”

B-site disorder driven Griffiths-like phase and electrochemical behavior in Y2NiCrO6 double perovskite

“…Furthermore, the deconvolution of the Cr (2p 3/2 and 2p 1/2 ) peaks (figure 3(c)) revealed four distinct peaks, demonstrating the coexistence of various Cr oxidation states. Specifically, the peak observed at 576.0 and 585.5 eV corresponds to Cr 2+ , whereas the peaks at 578.9 and 588.2 eV indicate Cr 3+ [13,[69][70][71]. The molar ratio of Cr 2+ to Cr 3+ was determined to be 41%:59%.…”

“…The O-1 s spectra (depicted in figure 3(d)) were subjected to deconvolution, resulting in the identification of three distinct peaks with binding energies situated at 529.1, 531.1, and 533.5 eV. These three peaks can be attributed to metal-oxygen bonds, oxygen vacancies, and surfaceadsorbed hydroxyl groups, respectively, with the molar ratio of 21%:61%:14% [69]. The oxygen vacancy (61%) of disordered YNCO double perovskite is much larger than the oxygen vacancy (35%) of a similar Dy-based transition metal double perovskite [72].…”

Comparison of the structure–property relationships between sillenite and perovskite phases of Bi0.9Dy0.1FeO3 nanostructures

“…Whereas, the colorless antibiotic CIP does not have visible light absorption properties and cannot take part in photosensitization reactions. 19 Therefore, in this investigation, the efficiency of the catalysts toward colored RhB and colorless CIP degradation was evaluated as a function of solar irradiation. Fig.…”

“…It is reported that the BiO 7 polyhedron with a dipole moment of 0.174 Debye might minimize electron-hole pair recombination and consequently improve the photocatalytic properties of the catalysts. 19 Notably, the perovskite and sillenite characteristics of bismuth ferrite are influenced by both its intrinsic properties and the flexibility with which those properties can be altered by various synthesis routes and their conditions. Therefore, several synthesis techniques have been developed, including solid-state reactions, co-precipitation, sol-gel, and hydrothermal synthesis, 7,[20][21][22][23] which have demonstrated a substantial impact on influencing the structure and morphology of bismuth ferrite, and consequently its physical properties.…”