An Investigation into the Influence of Graphene Content on Achieving a High-Performance TiO2-Graphene Nanocomposite Supercapacitor.

This study presents the synthesis of TiO2-graphene nanocomposites with varying mass ratios of graphene (2.5, 5, 10, 20 wt. %) using a facile and cost-effective hydrothermal approach. By integrating TiO2 nanoparticles with graphene, a nanomaterial characterized by a two-dimensional structure, unique electrical conductivity and high specific surface area, the resulting hybrid material shows promise for application in supercapacitors. The nanocomposite specimens were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman microscopy, field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Additionally, supercapacitive properties were investigated using a three-electrode setup by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) tests. Notably, the TiO2-20 wt. % rGO nanocomposite exhibited the highest specific capacitance of 624 F/g at 2 A/g, showcasing superior electrochemical performance. This specimen indicated a high rate capability and cyclic stability (93 % retention after 2000 cycles). Its remarkable energy density and power density of this sample designate it as a strong contender for practical supercapacitor applications.

One-Step Electrocatalytic Approach Applied to the Synthesis of ß-Propiolactones from CO2 and Dienes.

ß-Lactones are common substructures in a variety of natural products and drugs, and they serve as versatile synthetic intermediates in the production of valuable chemical derivatives. Traditional ß-lactone synthesis relies on laborious multi-step synthetic methods that use toxic compounds, sophisticated catalysts, expensive, and/or reactive chemicals. Based on the in situ electrochemical formation of metal-based nanoclusters, this paper describes the development of a one-step, room temperature electrocatalytic method for the formation of stable ß-lactone from CO2 and dienes. This one-step "electrosynthesis" method results in the formation of a new class of ß-lactone with high selectivity (up to 100%) and activity (up to 80% yields with respect to the reacted diene) by regulating the applied potential and current density. This work paves the way for more sustainable and environmentally friendly reaction pathways based on the in situ formation of nanoclusters as organic electrosynthesis catalysts.