Bimetallic CuAg Alloyed Nanoparticles Anchored on CdS Nanorods for the Photocatalytic Degradation of Enrofloxacin

The photocatalytic degradation of resistant antibiotics based on bimetallic alloys is considered an influential way for waste water treatment. In this work, nanoparticles of a CuAg bimetallic alloy are synthesized on the surface of CdS nanorods (NRs), which were employed as co-catalysts. The successful reduction of Cu and Ag ions via chemical reduction and the intimate contact between the alloy and NRs are investigated using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, energy-dispersive X-ray spectroscopy, ultraviolet–vis, and photoluminescence spectra. Anchoring of the CuAg alloy nanoparticles with CdS NRs has been proved to be due to the formation of Cu–S and Ag–S bonds, resulting in exceptional enhancement in the photocatalytic activity of CdS for removal of the enrofloxacin antibiotic. Bimetallic alloy nanoparticles of CuAg exhibit an enhancement of three times in the photocatalytic activity of the pristine CdS. Due to the synergistic effect between surface plasmon resonance light absorption of the CuAg alloy and the provided unique charge mobility channel in alloy–sulfur bonds on the surface, a Z-scheme pathway for photochemical transformations is proposed. A rate constant of 0.091 min –1 and an activation energy of 0.183 kJ mol –1 have been obtained from the CdS/CuAg photocatalyst under visible light, indicating remarkable catalytic activity. The CdS/CuAg system containing an alloy–sulfur bridge is reported in photocatalytic degradation for the first time, which is expected to shed light on research for the development of noble metal-based heterogeneous photocatalysts.