Ball milling-induced evolution of structural, optical, and catalytic properties in nanocrystalline ZrO ₂

Abstract Zirconium dioxide (ZrO 2 ) is widely recognized for its outstanding mechanical, thermal, and optical properties, making it a material of choice for advanced applications in catalysis, coatings, and other structural applications. In this study, monoclinic ZrO 2 is ball milled for various milling durations up to 40 h, and changes in the microstructure and phase are identified. A dominant monoclinic phase is observed along with a minor tetragonal phase when milled beyond 10 h, with corresponding crystallite size reduction and enhanced surface area with increased milling duration. The examined photoluminescence spectra revealed a noticeable reduction in the peak intensity, which is attributed to a drop in the charge recombination. The deconvolution of photoluminescence spectra indicates the suitability of 20 h sample for enhanced catalysis. In line with this, the catalytic reduction-assisted degradation of rhodamine B (RhB) demonstrated a substantial increase in the catalytic activity for the 20 h sample, with about 97.11% degradation in 40 min, verifying the suitability of ball milled ZrO 2 as an efficient catalyst for wastewater treatment.