Efficient catalytic reduction of xanthene based dyes, methylene blue, and 4-Nitrophenol using gold nanoparticles supported on mesoporous amine functionalized SBA-15

Resourceful catalytic materials and adsorbents are vital in treating various forms of organic pollutants that causes serious environmental effects. In the present work, amine (NH2) group functionalized ordered mesoporous silica SBA-15 has been utilized as solid support for gold nanoparticles (Au NPs, similar to 3%) dispersion under facile hydrothermal conditions. The mesoporous structure, Au nanoparticles dispersion and morphology of the synthesized AuNPs/NH2-SBA-15 catalyst were characterized by X-ray diffraction (XRD), N-2 Sorption, Fourier transform infrared spectrum (FTIR), High resolution scanning electron microscope (HRSEM) and transmission electron microscopy (TEM). The resultant AuNPs/NH2-SBA-15 material was explored for their catalytic reduction of rhodamine B (RhB), rhodamine 6G (Rh6G), rose bengal (RB), methylene blue (MB) and 4-nitrophenol (4-NP) using NaBH4 as the reducing agent. AuNPs/NH2-SBA-15 catalyst showed significantly higher activity for the reduction of organic molecules due to the synergistic effect of Ag NPs-inorganic silica SBA-15, mesoporous nature and effectual NH2- functionality. The reduction rate constants of RhB, Rh6G, RB, MB dyes and 4-NP over the nanocomposite catalyst in the presence of NaBH4 was 2.54 x 10(-2) s(-1), 5.73 x 10(-2) s(-1), 2.99 x 10(-2) s(-1), 3.56 x 10(-2) s(-1) and 73.7 x 10(-2) s(-1), respectively. Considering the reduction performance and kinetics, the AuNPs/NH2-SBA-15 materials are promising for catalytic applications in environmental waste-water treatment processes.