Search

Two new cadmium-containing Wells-Dawson polyoxometalates K8[α1-P2W17Cd(OH2)O61]•16H2O (α1-P2W17Cd) and K8[α2-P2W17Cd(OH2) O61]•16H2O (α2-P2W17Cd) were synthesized as aqueous soluble potassium salts. The cadmium-substituted complexes have been characterized by IR, 31P NMR, 113Cd NMR spectroscopy and cyclic voltametry (CV). Redox activities for the tungsten and cadmium centers have been observed by using cyclic voltammetry. It was found that the presence of cadmium decreases the electrocatalytic activity of the [α1-LiP2W17O61]9- and α2-[P2W17O61]10-heteropolyanions.

Understanding the properties of ionic liquids confined into nano-pores is required to use ionic liquids for many applications such as electrolytes for energy storage in capacitors and solar cells. Recently, polyoxometalate ionic liquids have attracted much attention for their potential applications in electrochemistry, catalysis, and nanotechnology. In this work, we have performed MD simulations on 1-ethyl-3-methylimidazolium Keggin ([emim] 3 [PW 12 O 40 ]) confined into armchair (20,20) CNTs to study the thermal properties and melting process. Changes in the simulated results of configurational energy of confined polyoxometallate IL indicated that the melting range of the confined polyoxometalate IL is about 650-750 K. Heat capacity at constant volume of the confined IL is about 2 (cal K -1 mol -1 ) which shows sharp changes around the melting range. The average number of hydrogen bonds (〈HB〉) of the confined IL is about 2.8 which also presents sharp changes around the melting range. The ion conductivity and self-diffusion coefficient of [emim] 3 [PW 12 O 40 ] IL also present a sharp maximum of 25 (S m -1 ) and 6 × 10 -10 (m 2 s -1 ) at the melting point. Our results did not show a significant hysteresis in the melting process and therefore, the process is reversible. Our simulation also indicated that the confinement of the polyoxometallate IL into the CNT increases its thermal stability and melting point. Our simulations also indicated that the type of CNT configuration has a small effect on the melting point of the confined polyoxometallate IL., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Among the important needs of human societies is the elimination of environmental pollution and also the construction of high-performance and inexpensive biosensors. In this regard, the construction of multi-functional composites has been considered. A novel magnetic graphite carbon nitride decorated by tri-vanadium substituted Dawson-type heteropolytungstate nanocomposite (C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 ) effectively synthesized and characterized by prevalent functional analysis. The prepared nano-catalyst presents bi-functional usage involving photocatalytic removal of dyes (methylene blue, congo red and phenyl red) (around 98%) under visible light radiation and greatly sensitive colorimetric sensing of cysteine in an aqueous media. Moreover, synthesized nano-catalyst successfully recovered five times without any considerable deficiency on its photocatalytic ability. Further, Moreover, we propose a novel method for cysteine detection based on the C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 nanocomposite. This nanocomposite displayed a privileged catalytic feature for cysteine oxidation to extend a clock reaction of methylene blue as an indicator in the presence of NaBH 4 in acidic solution. More importantly, this colorimetric sensing method of cysteine presents an easy, low-cost, selective, and rapid colorimetric assay with a detection limit value of 7.2 μM in the acceptable linear range of 5-600 μM., (Copyright © 2022 Elsevier Ltd. All rights reserved.)