Effect of pHs on the Structure Evolution of Platinum Nanoclusters and Their Surface Plasmon Resonance Properties

Multi-structured platinum nanoclusters have been prepared through a one-step aqueous synthetic process by controlling pHs. The included structures are closely packed 3-dimensional (3D) dendrites, loosely packed 3D dendrites, short-order dendritic chains, long-order dendritic chains, flatten nanoclusters and monodisperse nanoparticles. The high resolution transmission electron microscopy images (HRTEM) display that the nanoclusters with a variety of structures are filled with grains of average size ~2.0 nm. The images of the nanoclusters demonstrated that Pt nanoparticles were not fused to each other, but their aggregations were separated by cetyltrimethylammonium bromide (CTAB). The as-prepared Pt nanomaterials were studied by UV-visible absorption spectroscopy to identify their surface plasmon resonance (SPR) activities. The structure dependent SPR signals have been observed from 200 nm–800 nm.

Biocompatible Platinum Nanoclusters Prepared Using Bitter Gourd Polysaccharide for Colorimetric Detection of Ascorbic Acid

Ascorbic acid is an organic compound with antioxidant properties that can protect the human body from the threat of free radicals. Therefore, it is important to detect the existence and measure the concentration of ascorbic acid to regulate its content in the human body. In this work, we prepared bitter gourd polysaccharide (BGP)-stabilized platinum nanoclusters (Pt-BGP NCs) by reacting BGP with K2PtCl4. Pt-BGP NCs and catalyzed the decomposition of H2O2 to generate •OH radicals, which could oxidize TMB to form oxidized TMB (oxTMB), indicating their peroxidase-like properties. The kinetics followed the Michaelis–Menten equation. Furthermore, the colorimetric detection of ascorbic acid using Pt-BGP NCs showed high selectivity and a low detection limit of 0.191 μM. The accuracy of real sample detection using Pt-BGP NCs was as high as 98.9%. More importantly, Pt-BGP NCs had high cell biocompatibility and extremely low hemolysis rate due to the component of BGP. In summary, the prepared Pt-BGP NCs with reductive activity and good biocompatibility have good application prospects in colorimetric detection of ascorbic acid.

Simple and High-Yield Preparation of Carbon-Black-Supported ~1-nm Platinum Nanoclusters and Their Oxygen Reduction Reactivity

The improvement of oxygen reduction reaction (ORR) catalysts is essential before polymer electrolyte fuel cells can be used widely. To this end, we established a simple method for the size-selective...