Crystalline phase development and stability in CeO$_{\mathrm{2}}$-SiO$_{\mathrm{2}}$ nanofibers derived from electrospun precursors*

Ceria (CeO$_{\mathrm{2}})$ is a preferred catalytic material in applications found across many industries, including its use in water-gas shift reactions, automotive catalytic converters, and the removal of VOCs. Ceria nanofibers (NF) are attractive in such applications, but there are few reports on CeO$_{\mathrm{2}}$-based NF fabrication, phase development, and performance. One major obstacle in the development of CeO$_{\mathrm{2}}$ NF is their thermal stability and lack of sustainable production. It has been seen that CeO$_{\mathrm{2}}$ NF frequently disintegrate at increased temperatures. In the present study, a high-yield synthesis of CeO$_{\mathrm{2}}$ composite nanofibers with SiO$_{\mathrm{2}}$ was attained using alternating force electrospinning. Analyses of CeO$_{\mathrm{2}}$ NF crystallization process and resulting NF morphologies and structures were performed using TGA, FESEM/EDS, and XRD. CeO$_{\mathrm{2}}$-SiO$_{\mathrm{2\thinspace }}$NF with Ce:Si molar ratios from 1:4 to 4:1 were stable up to 1000 $^{\mathrm{o}}$C. They consisted of nanocrystalline CeO$_{\mathrm{2}}$ and amorphous SiO$_{\mathrm{2}}$, with no compound formation observed. Crystallization of SiO$_{\mathrm{2}}$ and CeO$_{\mathrm{2}}$ was noted at 1200\textdegree C, accompanied by the significant shrinkage and loss of fibrous structure. The obtained results demonstrate the improved thermal stability of complex oxide nanocrystalline CeO$_{\mathrm{2}}$-based nanofibrous ceramics.