Highly efficient nitrobenzene photoreduction over the amino acid-modified CdS-TiO₂ nanostructures under visible light

Abstract

CdS-coupled TiO₂ nanocrystals were prepared by the microemulsion-mediated solvothermal method at pretty low temperatures. The semiconductor nanocrystals were modified with tyrosine, phenyl alanine, glysine and glutamate aminoacids and then were characterized by BET, SEM, EDX, XRD, UV–Vis spectroscopy, and FTIR analysis methods. The specific surface area and the average pore diameter were found to be about 470 m² g⁻¹ and 2.8 nm, respectively. Moreover, the average size of the CdS-TiO₂ particles was evaluated to be 28 nm. The results showed that the modification process with the aminoacids improves the adsorption capability and photoactivity of the samples. Among them, tyrosine was determined to be the best choice. According to the results, modification of CdS-TiO₂ heterojunction photocatalyst with electron-donating groups is an efficient strategy to increase the photoreduction of nitroaromatic compounds. Reusability experiments were also carried out and confirmed the high capacity of the prepared samples for the photoconversion of nitrobenzene after being repeated for four times.