Photochemical Synthesis and Catalytic Applicationsof Gold Nanoplates Fabricated Using Quercetin Diphosphate Macromolecules

摘要

The demand for safer design and synthesis of gold nanoparticles (AuNPs) is on the increase with the ultimate goal of producing clean nanomaterials for biological applications. We hereby present a rapid, greener, and photochemical synthesis of gold nanoplates with sizes ranging from 10 to 200 nm using water-soluble quercetin diphosphate (QDP) macromolecules. The synthesis was achieved in water without the use of surfactants, reducing agents, or polymers. The edge length of the triangular nanoplates ranged from 50 to 1200 nm. Furthermore, the reduction of methylene blue was used to investigate the catalytic activity of AuNPs. The catalytic activity of triangular AuNPs was three times higher than that of the spherical AuNPs based on kinetic rate constants (k). The rate constants were 3.44 × 10^–2 and 1.11 × 10^–2 s^–1 for triangular and spherical AuNPs, respectively. The X-ray diffraction data of gold nanoplates synthesized by this method exhibited that the nanocrystals were mainly dominated by (111) facets which are in agreement to the nanoplates synthesized by usingthermal and chemical approaches. The calculated relative diffractionpeak intensity of (200), (220), and (311) in comparison with (111)was found to be 0.35, 0.17, and 0.15, respectively, which were lowerthan the corresponding standard values (JCPDS 04-0784). For example,(200)/(111) = 0.35 compared to 0.52 obtained from the standard (JCPDS04-0784), indicating that the gold nanoplates are dominated by (111)facets. The calculated lattice from selected area electron diffractiondata of the as-synthesized and after 1 year nanoplates was 4.060 and4.088 Å, respectively. Our calculations were found to be in agreementwith 4.078 Å for face-centered cubic gold (JCPDS 04-0784) andliterature values of 4.07 Å. The computed QDP–Au complexdemonstrated that the reduction process took place in the B ring ofQDP. This approach contributes immensely to promoting the ideals ofsustainable nanotechnology by eradicating the use of hazardous andtoxic organic solvents.