A simple and generic approach for synthesizing colloidal metal and metal oxide nanocrystals

Abstract

A simple and generic approach--alternating voltage induced electrochemical synthesis (AVIES)--has been reported for synthesizing highly dispersed colloidal metal (Au, Pt, Sn, and Pt-Pd) and metal oxide (ZnO and TiO2) nanocrystals. The respective nanocrystals are produced when a zero-offset alternating voltage at 60 Hz is applied to a pair of identical metal wires, which are inserted in an electrolyte solution containing capping ligands. In the case of Au, the obtained nanocrystals are highly crystalline nano-icosahedra of 14 ± 2 nm in diameter, the smallest Au icosahedra synthesized in aqueous solutions via green chemistry. Their catalytic activity has been demonstrated through facilitating the reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride. This AVIES approach is an environmentally benign process and can be adopted by any research lab.

Carbon quantum dot coated Mn3O4 with enhanced performances for lithium-ion batteries

“…31 And then high valence MnO x could be reduced through cathodic process (I) and transformed into stable Mn 3 O 4 nanocrystals in NaCl solution. Mn atoms were firstly oxidized to high valence Mn oxide (MnO x ) films on the surface of Mn electrodes by anodic process.…”

A simple and effective method for controllable synthesis of silver and silver oxide nanocrystals

“…Previously, this AVIES method has been developed to synthesize several types of metal (such as Pd, Pt, Au, and Sn) and metal oxide (such as ZnO and TiO 2 ) NCs. [63][64][65] However, the metal and the metal oxide NCs were not from the same elements. Aer analyzing the reduction potentials of these elements (Table S1 †), 66,67 we hypothesized that producing metal and metal oxide NCs of the same element would require a metal element that is less noble than Pd (E Pd 2+ /Pd 0 ¼ 0.92 V) and more noble than Cu (E Cu 2+ /Cu 0 ¼ 0.340 V), for which Ag was identied as a promising candidate (E Ag + /Ag 0 ¼ 0.799 V).…”

Controllable synthesis of nanostructured metal oxide and oxyhydroxide materials via electrochemical methods

“…In terms of particle shape and size control, the produced ZnO nanorods suffered from poor size and shape homogeneity, whilst the TiO 2 lacked well-defined nanostructure, even in the presence of a capping agent. [66] Similarly, the as-produced Co oxyhydroxide material suffered from poor nanostructure homogeneity. [67]…”