Mechanochemical synthesis of Au, Pd, Ru and Re nanoparticles with lignin as a bio-based reducing agent and stabilizing matrix

Abstract

A versatile, low-energy and solvent-free method to access nanoparticles (NPs) of four different transition metals, based on a bottom-up mechanochemical procedure involving milling of inorganic precursors, is presented. Lignin, a biomass waste, was used effectively as a reducing agent, for the first time in a mechanochemical context, to access MNPs where M = Au, Pd, Ru, Re. A series of metal precursors was used for this reaction and their nature was shown to be integral in determining whether NPs became incorporated within the organic lignin matrix, M@lignin, or not. Specifically, organometallic precursors resulted in extensive encapsulation of the NPs, as well as improved control over their size and shape, while ionic precursors afforded matrix-free NPs. The resulting NP-containing composites were characterized through Fourier-transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (PXRD). This mechanochemical grinding method for accessing M@lignin (M = Au, Pd, Ru and Re) is significantly more sustainable than the traditional solvent batch syntheses of metal NPs because it relies on the use of a biomass-based polymer, it is highly atom economical, it eliminates the need for solvents and it reduces drastically the energy input.

ZnO nanoflowers: Novel biogenic synthesis and enhanced photocatalytic activity

“…The nanoparticles found to have inimitable size dependent physiochemical properties in contrast to their bulk materials [7]. To meet the growing demands researchers have found many ways for the synthesis of nanoscale metal/semiconductor materials by chemical [8], physical methods [9] and biological methods concerning the use of plant extracts [10][11] and fungi [12][13]. But in recent time many researchers are using bacterial strains for synthesis of various nanoparticles, as an eco-friendly reducing and capping agent.…”

Systematic studies on mechanochemical synthesis: Schiff bases from solid aromatic primary amines and aldehydes

“…In a recent Faraday discussion‐themed issue on “ Mechanochemistry: From Functional Solids to Single Molecules, ” the mechanochemistry of organic molecules, soft materials and pharmaceuticals, the mechanochemistry of inorganic compounds and coordination‐based materials, sonication and macromolecular mechanochemistry, current theoretical models for mechanochemical reactions, the mechanistic and kinetic understanding, catalysis, and scaling up of mechanochemistry were broadly discussed …”

Hydrogenation of allyl alcohols catalyzed by aqueous palladium and platinum nanoparticles

“…[21][22][23][24][25][26] Metal nanoparticles (NPs) are becoming increasingly attractive for industrial catalysis, thanks to their high surface-to-volume ratio, easy preparation and tunable dimensions. [36][37][38][39][40][41] In the present study, we investigated the hydrogenation of allyl alcohols catalyzed by Pt and Pd NPs, stabilized by lignins and prepared according to our previously published method. [29][30][31][32][33][34][35] However, the preparation of metal NPs often involves the use of environmental unfriendly organic solvents.…”