3 research outputs found
Graphene Oxide Hybrid with Sulfur–Nitrogen Polymer for High-Performance Pseudocapacitors
Toward the introduction of fast faradaic pseudocapacitive behavior and the increase of the specific capacitance of carbon-based electrodes, we covalently functionalized graphene oxide with a redox active thiourea-formaldehyde polymer, yielding a multifunctional hybrid system. The multiscale physical and chemical characterization of the novel 3-dimensional hybrid revealed high material porosity with high specific surface area (402 m2 g–1) and homogeneous element distribution. The presence of multiple functional groups comprising sulfur, nitrogen, and oxygen provide additional contribution of Faradaic redox reaction in supercapacity performance, leading to a high effective electrochemical pseudocapacitance. Significantly, our graphene-based 3-dimensional thiourea-formaldehyde hybrid exhibited specific capacitance as high as 400 F g–1, areal capacitance of 160 mF cm–2, and an energy density of 11.1 mWh cm–3 at scan rate of 1 mV s–1 with great capacitance retention (100%) after 5000 cycles at scan rate of 100 mV s–1
Manganese-Catalyzed C(sp2)H Borylation of Furan and Thiophene Derivatives
Aryl boronic esters are bench-stable, platform building-blocks that can be accessed through metal-catalyzed aryl C(sp2)-H borylation reactions. C(sp2)-H bond functionalization reactions using rare- and precious-metal catalysts are well established, and while examples utilizing Earth-abundant alternatives have emerged, manganese catalysis remains lacking. The manganese-catalyzed C-H borylation of furan and thiophene derivatives is reported alongside an in situ activation method providing facile access to the active manganese hydride species. Mechanistic investigations showed that blue light irradiation directly affected catalysis by action at the metal center, that C(sp2)-H bond borylation occurs through a C-H metallation pathway, and that the reversible coordination of pinacolborane to the catalyst gave a manganese borohydride complex, which was as an off-cycle resting state