Innovative synthesis and performance enhancement of yttria-stabilized zirconia nanocrystals via hydrothermal method with Uncaria gambir Roxb. leaf extract as a capping agent

Yttria-stabilized zirconia (YSZ) is a ceramic material with versatile applications, yet its synthesis and performance improvements remain essential. This study introduces an innovative hydrothermal synthesis method with pH control and Uncaria gambir Roxb., extract as a bio-capping agent for YSZ nanocrystals with the composition Zr 0.92 Y 0.08 O 1.96 . Structural analysis revealed that the capping agent led to a single-phase cubic structure, enhancing YSZ stability and performance. Scanning electron micrographs showed improved particle homogeneity and reduced agglomeration in the presence of the bio-capping agent. Infrared spectroscopy highlighted the vibrational features of YSZ, including O-Y-O and Zr(Y)-O bonds. The bio-capping agent significantly affected YSZ ionic conductivity and activation energy for ionic migration. These findings underscore the potential of utilizing Uncaria gambir Roxb. leaf extract as a bio-capping agent to enhance the structural stability and ionic conductivity of YSZ nanocrystals, with implications for applications in solid oxide fuel cells and other ionic transport systems. • Innovative hydrothermal synthesis of YSZ nanocrystals • Bio-capping agent enhances YSZ stability/performance • Improved particle homogeneity and reduced agglomeration • Significant impact on YSZ ionic conductivity • Implications of YSZ for solid oxide fuel cells and ionic transport