Abstract
This study reports the synthesis and photocatalytic performance of MnCo(2)O(4) nanospinels fabricated with biodegradable stabilizers-chitosan (CHT) and biomass-cellulose (BC)-for the degradation of methylene blue (MB) under UV-rich solar irradiation. Structural and optical analyses (FTIR, XRD, XPS, PL, TGA, UV-Vis, and BET) revealed that the stabilizers significantly improved crystallinity, porosity, and charge-carrier separation while suppressing electron-hole recombination. Among the catalysts, MnCo(2)O(4)-CHT exhibited the best performance, achieving 96% MB degradation within 120 min, with the highest apparent rate constant (k(app) = 0.0203 min(-1)) and shortest half-life (t(1)/(2) = 34.2 min). In comparison, MnCo(2)O(4)-BC and MnCo(2)O(4)-Neat achieved 65% and 45% degradation, respectively. The enhanced activity of MnCo(2)O(4)-CHT is attributed to the chelation and electron-donating ability of chitosan's -NH(2) and -OH groups, which facilitate efficient charge transfer and reactive oxygen species (ROS) generation. These findings demonstrate the effectiveness of stabilizer-assisted synthesis in tuning the physicochemical properties of spinel oxides, offering a sustainable and high-performance photocatalyst for environmental remediation and wastewater treatment applications.