Transition metal-doped CuO nanosheets for enhanced visible-light photocatalysis

Herein, we report a comprehensive investigation of Zn- and Fe-doped CuO nanosheets as promising photocatalysts for the degradation of organic dyes. These nanosheets were synthesized via a hydrothermal process and thoroughly characterized through spectroscopic and microscopic techniques. Photocatalytic degradation experiments using methylene blue (MB) and malachite green (MG) revealed a marked increase in efficiency within the doped CuO nanosheets when compared to their undoped counterparts. The degradation kinetics showed MB following a zero-order model and MG following a first-order model. In particular, Zn and Fe-doped CuO nanosheets outperformed undoped CuO, degrading 66% and 73% of MB and 85% and 90% of MG within specific timeframes, while undoped CuO achieved 62% and 76% degradation, respectively. Computational analysis conducted with Gaussian 09 software pinpointed reactive sites susceptible to radical and electrophilic attacks in the dyes. The enhanced performance is credited to transition metal doping, which induces a red shift in the optical band gap, thereby improving visible light absorption and diminishing electron-hole recombination. This study underscores the potential of transition metal doping in bandgap engineering for efficient visible lightassisted photocatalytic remediation.