Synthesis and visible-light photocatalytic property of spinel CuAl2O4 for vehicle emissions.

Abstract

Photodegradation of vehicle emissions is a promising approach for dealing with atmospheric pollution in road tunnels. In this research, copper aluminate nanoparticles (CuAl2O4) were prepared by the sol-gel method using copper nitrate, aluminum nitrate, and citric acid as precursor materials. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy to validate their structure, surface morphology, and optical properties, respectively. The XRD and SEM results confirm that the CuAl2O4 powder has a particle size of 20-37nm and exhibits a spinel-type structure. The upper limit of the stimulation wavelength in the UV-Vis diffuse reflectance spectrum is located at 725nm with a band gap (Eg) of about 1.50eV, which is suitable for effective visible-light degradation. Photocatalytic performance of the CuAl2O4 nanoparticles was analyzed by investigating the effects of light source, calcination temperature, and catalyst loading amount on the degradation of vehicle emissions (CO, HC, and NO). Best results were obtained under fluorescent light irradiation by CuAl2O4 nanoparticles calcined at 700°C. The optimum catalyst amount for decomposing CO, HC, and NO were determined as 0.5g, 0.5g, and 2g, respectively. Overall, the photocatalytic performance study verifies that spinel CuAl2O4 photocatalyst is a valuable material for next-generation technologies aimed at reducing harmful emissions from vehicles.