Seminar Title
Synthesis and characterization of novel perovskite based semiconducting leadfree ferroelectric oxides
Seminar Type
Progress Seminar
Ceramic Engineering
Speaker Name
Monika Singh ( Rollno : 519cr1002)
Speaker Type
Seminar Room of Department of Ceramic Engineering
Date & Time
25 May 2023 10:00 AM
Prof. Ranabrata Mazumder

Ferroelectric materials are studied for the photocatalytic applications due to their internal polarization. However, the efficiency of these materials are low because they possess wide band gap (>3eV) due to which they show absorbance in only UV region. To overcome this issue, different techniques have been developed like fabrication of nanocomposite with narrow band gap oxides, gaining control over particle size and particle morphology, and designing narrow band gap ferroelectric material. Barium calcium zirconate titanate (Ba0.85Ca0.15Zr0.1Ti0.9)O3 or BCZT material holds extraordinary ferroelectric properties with high piezoelectric coefficient (d33 = 620 pC/N) and very high dielectric constant (approx. 3500 at room temperature). But due to its high optical bandgap (~3.12 eV), absorption in visible region is restricted. So, to make it a visible light active photocatalyst, its band gap should be modified with the doping of transition metal oxides (Ni, Co, Fe and Cu) with retention of ferroelectricity. Also, formation of heterostructure with low band gap oxide materials can help to facilitate efficient charge carrier generation and their separation for better photocatalytic activity.

In present work BCZT was synthesized via two different routes i.e., solution combustion and electrospinning route, after that heterojunction nanocomposite of BCZT powder/nanofiber-Ag2O with different weight ratios (75:25, 50:50 and 25:75) were prepared by precipitation method. The powder samples were characterized by XRD, FESEM, TEM, and PL spectroscopy. The photocatalytic results showed that BCZT powder/nanofiber-Ag2O (50:50) nano-composite can completely mineralize RhB dye in 35 minutes under visible light irradiation, which is better than those of pure BCZT nanofiber and Ag2O powder independently. An improved photocatalytic activity was attributed to the formation of heterostructure between BCZT and Ag2O which has excellent visible light absorption and more separation efficiency. Ni doped BCZT was also synthesized by solid state route where Ni concentrations varied in the range of 0.01-0.05 mol% and resultant ceramics were characterized for structural, dielectric, ferroelectric, electrical, optical and photocatalytic properties.