Preparation of monometallic and bimetallic alloy nanoparticles stabilized with sulfobetaine-based block copolymer and their catalytic activities

Production of NiO, NiO/Ag, NiO/Au, and NiO/Pt hollow spheres by using block copolymer stabilized microspheres as a template

“…The styrene monomer was purified by passing through basic alumina (SI‐AL) column. Small diameter Au, Ag, and Pt nanoparticles were produced and characterized as reported in our previous study 37,38 …”

“…NiSO 4 solution (0.20 M, 10.0 ml) was then added and stirred for 24 h. Then, 3.0 g of urea was dissolved in water (10.0 ml) and added to the reaction medium and stirred at 80 °C for 48 h. At the end of the reaction, the pH of the medium was around 12 due to urea decomposition and ammonia formation. The production of NiO/metal NPs hollow spheres was accomplished by adding 1.0 ml of Au (4.50 ± 1.1 nm), Ag (7.95 ± 1.4 nm), and Pt (3.80 ± 0.6 nm) nanoparticle dispersions, which we previously produced, together with the NiSO 4 solution 37,38 . The product was centrifuged three times at 5000 rpm and washed 3 times with distilled water.…”

Polymer microgels for the stabilization of gold nanoparticles and their application in the catalytic reduction of nitroarenes in aqueous media

“…The catalytic reductive reaction of nitroarenes using NaBH 4 reductant in the presence of efficient and highly stable Au nanoparticles supported on suitable systems in water presents a solution to all the above-mentioned problems. 32 Surfactants, 33 ionic liquids, 34 dendrimers, 35 block copolymers, 36 and microgels 37 are used as supporting systems to stabilize Au nanoparticles and to enhance their catalytic activity.…”

Polyampholytic Poly(dehydroalanine) Graft Copolymers as Smart Templates for pH-Controlled Formation of Alloy Nanoparticles

“…In an aqueous environment, water-soluble polymers or hydrogels are ideal templates to obtain NPs within a defined surrounding or to support biomineralization. , Typically, the interaction of such materials with metal salts leads to the formation of polymer–ion complexes, for example, within a three-dimensional network or micelles. In this way, controlled growth alongside with stabilization of the resulting inorganic materials upon reduction is enabled. − As one example, Ni, Au, Ag, or AuAg alloy NPs could be prepared within a hydrogel network and applied for catalysis. ,, Similarly, Ag nanocapsules were prepared using a thermo-responsive hydrogel core or a complexation/reduction approach, employing double hydrophilic copolymers as templates. , …”

“…As the composition affects spectroscopic properties, shifts in the optical absorbance of the surface plasmon resonance peak can often be directly correlated with the composition of bimetallic particles, ,, and this phenomenon was recently exploited in the multicolor tracking of single biomolecules . Other examples of bimetallic NPs include Ni, Pt, Pd, Fe, and Cu, as outlined by Sharma et al The synthesis of AgAu NPs can be performed by coreduction of the corresponding metal salts, most often AgNO 3 and H­[AuCl 4 ] in different ratios. ,− Stabilization of these nanoalloys is usually achieved by the addition of surfactants, either monomeric, such as sodium dodecyl sulfate, or dodecanethiol, as well as water-soluble polymers, for example, poly­(acryl amide), poly­( N -vinyl pyrrolidone), starch, poly­(vinyl alcohol), poly­(diallyldimethylammonium chloride), dendrimers, or double hydrophilic block copolymers . Besides these examples, polyelectrolyte multilayers, interpolyelectrolyte complexes, or hydrogels also can serve as host matrices, , and during the reduction step, both temperature and pH value play an important role. − Although energy-dispersive X-ray (EDX), atomic absorption spectroscopy, and X-ray photoelectron spectroscopy (XPS) permit absolute determination of the alloy composition, cyclic voltammetry and UV–vis spectroscopy give qualitative evidence and are typically used to analyze the electrochemical and optical properties.…”