Biosynthesis of Gold Nanoparticles by Foliar Broths: Roles of Biocompounds and Other Attributes of the Extracts

Biosynthesis of nanoparticles has arisen as a promising alternative to conventional synthetic methodologies owing to its eco-friendly advantages, and the involved bioprotocol still needs further clarification. This research, for the first time from the standpoint of statistics, confirmed an electrostatic force or ionic bond-based interaction between the chloroauric ions and the involved bioconstituents and manifested that reducing sugars and flavonoids were both important reductants responsible for conversion of Au(III) to Au(0). The result also demonstrated that the proteins were not the reducing agents, yet they might be protection agents in biosynthesis of gold nanoparticles (GNPs). Besides, a significant linear relationship was found between the anti-oxidant ability of the foliar broths and their capability to reduce Au(III) into Au(0). Furthermore, the preliminary investigation based on the boxplot on the size/shape distribution of the biosynthesized GNPs revealed that gold nanospheres with higher degree of homogeneity in size tended to be promoted by foliar broths containing higher content of reducing sugars/flavonoids and proteins. Otherwise, i.e., for those broths with lower content of the above biocompounds, sphere GNPs of wider size distribution or even gold nanotriangles tended to be fabricated

Electro-Catalytic Behavior of Silver Nanoparticles Embedded in Potato and Tapioca Starch for Oxygen Reduction Reaction

The present work demonstrates an eco-friendly and facile method for the synthesis of tapioca and potato starches incorporated by silver nanoparticles hereafter named (T-Ag/NPs) and (P-Ag/NPs), respectively. The analysis of UV–vis showed the appearance of surface plasmon resonance. The TEM analysis shows the formation of highly distributed Ag/NPs with an average diameter and standard deviation of 19.65 ± 2.45 and 12.27 ±7.39 nm for (P-Ag/NPs) and (T-Ag/NPs), respectively. The prepared (T-Ag/NPs) show remarkable potential applicability in energy as low-cost electrode material compared with (P-Ag/NPs). They are used as a non-precious catalyst for oxygen reduction reaction (ORR) in the alkaline medium. The presence of starch promotes long-term stability up to 1000 cycles and avoid the dissolution and agglomeration of silver nanoparticles. The (T-Ag/NPs) show significant stability and reproducibility