Characterization\nof Bimetallic Pd–Fe Nanoparticles\nSynthesized in Escherichia coli

Biologically mediated nanoparticle (NP) synthesis offers\na reliable\nand sustainable alternative route for metal NP production. Compared\nwith conventional chemical and physical production methods that require\nhazardous materials and considerable energy expenditure, some microorganisms\ncan reduce metal ions into NPs during standard metabolic processes.\nHowever, to be considered a feasible commercial option, the properties\nand inherent activity of bio-NPs still need to be significantly improved.\nIn this work, we present an Escherichia coli-mediated synthesis method for catalytically active Pd–Fe\nNPs. The produced biogenic Pd–Fe NPs with varying Fe content\nwere characterized using complementary analytical techniques to assess\ntheir size, composition, and structural properties. In addition, their\ncatalytic performance was assessed by using standardized chemical\nreactions. We demonstrate that the combination of Pd with Fe leads\nto synergistic effects that enhance the catalytic performance of Pd\nNPs and make biogenic Pd–Fe NPs excellent potential substitutes\nfor currently used catalysts. Briefly, the apparent rates for the\nmodel reaction of 4-nitrophenol reduction to 4-aminophenol catalyzed\nby Pd-based nanoparticles were as high as 0.1312 min<sup>–1</sup> using bimetallic Pd–Fe NPs, which is far superior to the\nrates of monometallic Pd NPs counterparts. This study provides a feasible\nstrategy for the synthesis of multimetallic Pd-based NPs using common\nmicrobial processes. It emphasizes the potential of biogenic Pd–Fe\nNPs as efficient and sustainable catalysts for hydrogenation reactions,\noffering an environmentally friendly synthesis for various applications,\nincluding wastewater treatment and the production of fine chemicals.