Chelating agent size effect on thermal decomposition, phase formation and morphology characteristics of Y3+ doped Ba(Ce,Zr)O3 ceramics powder prepared by a sol-gel process

This present work reports the facile sol-gel synthesis of Y 3+ doped Ba(Ce,Zr)O 3 with composition of BaCe 0.54 Zr 0.36 Y 0.10 O 2.95 (BCZY). Series of six samples were prepared using various chelating agents namely citric acid (denoted as S1, 210 g/mol), tartaric acid (S2, 150 g/mol), glycolic acid (S3, 70 g/mol), nitriloacetic acid (S4, 191 g/mol), ethylenediaminetetraacetic acid (S5, 292 g/mol) and triethylenetetramine (TETA) (S6, 146 g/mol). The influence of chelating agents’ molecular weight ( M w ) and functional group on thermal decomposition, phase formation and morphology of BCZY were explored. The reaction products obtained after heat treatment were characterized by Thermal Gravimetric Analyzer (TGA), Fourier Transform Infrared (FTIR) spectrometer, X-ray diffractometer (XRD) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX) spectrometer. TGA along with FTIR analysis confirmed that the thermal decomposition of all samples achieved almost completion at processing temperature below 1000 °C. TGA verified the weight loss of intermediate compounds increased with an increase in the M w of the chelating agents in the following trend: S3 (28%) < S6 (35%) < S2 (40%) < S4 (90%) < S1 (93%) < S5 (95%). At calcination temperature of 1100 ° C, XRD pattern of all samples excluding S4 showed successful formation of single-phase BCZY crystals. The highest percentage (99.5%) of BCZY perovskite phase was achieved for S6. In contrast, S4 exhibited 57.5% secondary phase of BaCeO 3 and 42.5% BCZY, suggesting incomplete formation of the required perovskite phase. SEM revealed all calcined powders have similar morphology of clump-like network structure. The use of different types of chelating agents interacts with different atomic radius of metal cations resulted in the formation of Zr-cluster and Ce-cluster, suggesting the possible cause for the fluctuations observed in the EDX elemental composition of the calcined powders. • Six chelating agents were used to prepare BCZY composite using sol-gel method. • Amino-based chelating agent is effectively retarded the BaCO 3 formation. • TETA showed the highest total weight loss and perovskite phase percentage. • N -donor chelating agent favors a complete substitution of Zr 4+ at Ce 3+ sites.