Cu–Ag Alloy Nanoparticles in Hydrogel Nanofibers for the Catalytic Reduction of Organic Compounds

Abstract

Nanoalloys or alloy nanoparticles containing multiple metals are of great interest because the combination of multiple metals in close proximity can grant enhanced properties including stability, activity, and selectivity arising from synergism that cannot be accessed by the combination of individual metals. In this study, we have produced nanoalloys in stable flexible electrospun hydrogel nanofibers composed of poly(acrylic acid) and poly(allylamine hydrochloride). The hydrogel fibers were loaded with metal ions such as copper and silver through an immersion in metal salt solutions followed by a chemical reduction to form the metal nanoparticles. The hydrogel matrix allowed for the absorption of metal ions into the fibers and provided a viscous environment to promote the formation of alloy particles in the small diameter range (<25 nm). The proposed fabrication process is advantageous in terms of simplicity, controllability, and versatility. The reductions of 4-nitrophenol and methylene blue were performed to test and compare the catalytic activity of monometallic nanoparticles and copper−silver bimetallic nanoparticles. The copper−silver bimetallic nanoparticles demonstrated preferred selectivity for the reduction of 4-nitrophenol and higher catalytic activity for the reduction of methylene blue. Overall, we have developed promising stable flexible nanocomposites for catalytic reduction of organic redox compounds, and other catalytic nanoalloy systems could be further studied by modification of the procedure.

Recent Developments in Plasmonic Alloy Nanoparticles: Synthesis, Modelling, Properties and Applications

“…Co-reduction is well suited for the deposition of alloy nanocrystals on substrates such as fibers, as demonstrated with CuÀ Ag NPs obtained by immersion of electrospun hydrogels in a solution containing both CuSO 4 and AgNO 3 and addition of NaBH 4 . [67] Often, the seeded growth technique is exploited, in which the alloy is formed on pre-existing metal seeds which facilitate the control over shape and size. AuÀ Pd nanostructures have been synthesized starting from Au nanorods (NRs) made by the seed-mediated method and, subsequently, the Pd was added in different concentrations to change the resulting NRs morphology.…”

“…The Cu/Au/Pt TMNPs had an irregular shape and an average size of ∼10 nm, although the three elements were uniformly distributed. Co‐reduction is well suited for the deposition of alloy nanocrystals on substrates such as fibers, as demonstrated with Cu−Ag NPs obtained by immersion of electrospun hydrogels in a solution containing both CuSO 4 and AgNO 3 and addition of NaBH 4 [67] …”

Recent developments in hydrogels containing copper and palladium for the catalytic reduction/degradation of organic pollutants

“…Li et al synthesized nanostructures of steady flexible electrospun hydrogel nanofibers comprised of poly(allylamine hydrochloride) and poly(acrylic acid). 86 The metal NPs were formed by loading the hydrogel fibers with metal ions such as Ag and Cu and immersing them in solutions with metal ions after chemical reduction. Finally, the metal ions were absorbed from the medium by the hydrogel fibers.…”

Electroless Metallization of the Elements: Survey and Progress

“…EL Cu and Cu alloys − also represent attractive substrates for SERS-based sensors. The ∼550–1250 nm localized surface plasmon resonance (LSPR) range of low-cost Cu overlaps and slightly exceeds that of more expensive Au for substrate preparation .…”