Gold–Platinum Bimetallic Nanoclusters for Oxidase-like Catalysis

Abstract

Guanosine monophosphate (GMP)-protected bimetallic nanoclusters of gold and platinum, Au–PtNCs-GMP, were prepared through an improved hydrothermal method under basic conditions, which show high catalytic activity for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and 2,2′-azino-bis­(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) under ambient conditions. Further systematic optimization of synthesis provides the best catalyst by feeding the materials 0.8 mM HAuCl4, 0.2 mM H2PtCl6, 4.0 mM NaOH, and 3.0 mM GMP, which reacted at 120 °C for 30 min, which show an initial maximum velocity (V max) of 253.8 × 10–8 M s–1 for TMB as the substrate. Such a value is at the top among the oxidase mimetics reported, which is essentially attributed to the synergistic effect between two metals in the small nanocluster. Moreover, the achieved Au–PtNCs-GMP show a short reaction time of 60 s for the oxidation of substrates, which is much faster than the previously reported ones. The in-depth mechanistic studies by 1H and 31P NMR spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy of the optimized Au–PtNCs-GMP reveal them to be of ultrasmall size with a unique ligand structure, particularly the synergistic effect between the two metals endow the product with a high catalytic performance. Therefore, the present study not only provides a novel bimetallic nanocluster as a good catalyst with highly efficient oxidase mimetics but also opens a way for the development of other oxidase mimetics.

Lysozyme-Functionalized 5-Methyl-2-thiouracil Gold/Silver Nanoclusters for Luminescence Assay of Alkaline Phosphatase

“…Bimetallic nanoclusters (NCs) have aroused tremendous research interest compared with monometallic nanoclusters, which has been due to the fact that bimetallic nanoclusters integrate the synergetic effects from two metal atoms and exhibit an excellent performance in the fields of sensing, 1 bioimaging, 2 electrochemistry, 3 and catalysis. 4 Meanwhile, the monodisperse NCs are easily obtained via various synthesis strategies (microwave-assisted methods, 5 hydrothermal, 6 heating and stirring method, 7 etc.) and numerous ligands (thiolates, 8 peptides, 9 proteins, 10 polymers, 11 and phosphines 12 ).…”

Photoenzymatic Activity of Artificial–Natural Bienzyme Applied in Biodegradation of Methylene Blue and Accelerating Polymerization of Dopamine

“…The rational explanation might be that the supersmall size of the platinum nanozyme enabled it to absorb more ABTS molecules than free laccase. Thus, the platinum nanozyme possessed a better catalytic activity than other platinum catalysts …”

“…Thus, the platinum nanozyme possessed a better catalytic activity than other platinum catalysts. 52 3.6. Biodegradation of Methylene Blue.…”

Origin of luminescence properties and synthetic methods for gold- and bimetallic gold-based nanomaterials

“…26A and B). 247 One year later, the same group proposed another method for the hydrothermal synthesis of GSH-stabilized Au–Pt BMNCs, which possessed both visible emission at 625 nm and NIR emission band at 805 nm, and finally utilized them towards the detection of Ag( i ). An aqueous solution containing HAuCl 4 and K 2 PtCl 4 (8 : 1) was mixed with GSH and sodium citrate, and finally autoclaved with varying temperature and time to get pure BMNCs.…”