Boosting potassium-storage performance via confining highly dispersed molybdenum dioxide nanoparticles within N-doped porous carbon nano-octahedrons

Preparation of Progressive Driving Bilayer Polymer-Dispersed Liquid Crystals Possessing a PDLC-PVA-PDLC Structure

In this paper, the bilayer polymer-dispersed liquid crystals possessing a PDLC-PVA-PDLC structure were prepared by integrating two monolayer PDLCs. The effect of the polymer mesh size on the electro-optical properties of a bilayer PDLC was investigated by comparing the micro-morphology and electro-optical curves under different polymerization conditions. In addition, the impact of doping MoO2 nanoparticles with surface modification on the comprehensive performance of the bilayer PDLC was further researched. The contrast ratio of the bilayer PDLC prepared under the optimal conditions was improved by more than 90% and still maintained excellent progressive driving performance. Therefore, the development of a bilayer PDLC with optimal electro-optical properties will significantly enhance the technological prospects for the application of PDLC-based devices in smart windows, displays, and flexible devices.

A Sustainable Approach to the Preparation of MoO2 Quantum Dots and the Pseudocapacitive Performance before and after Calcination

The present preparation methods of molybdenum dioxide (MoO2) quantum dots (QDs) are often cumbersome and not environmentally friendly, and more importantly, the prepared MoO2 QDs are usually wrapped in surfactants, which are difficult to be removed and impact their intrinsic characterization and performance. Herein, we present a facile, scalable and sustainable approach to obtain clean and pure MoO2 QDs (1.5~3 nm), which consists of a hydrothermal reaction and a further calcination process in vacuum following freeze drying. Furthermore, the influence of calcination temperature, atmosphere and time is also studied. The calcination at 400 °C for 2 h in vacuum can efficiently remove the surfactants wrapping on the MoO2 QDs without obvious size change, whereas the calcination in nitrogen will lead to a slight increase in size, and the calcination in air could transform MoO2 QDs into MoO3 nanoplates. In addition, the pseudocapacitive performance of the as-prepared samples is tested and compared by electrochemical methods, and the specific capacitance of the clean MoO2 QDs is about 1.4 times larger than that of MoO2 QDs with surfactants at 5 mV s−1. This study also demonstrates a possible way to efficiently remove the organic substance wrapping on quantum dot materials.