Oxygen

About: Oxygen is a research topic. Over the lifetime, 48149 publications have been published within this topic receiving 1113788 citations. The topic is also known as: O & Oxygen.

Aqueous Au-Pd colloids catalyze selective CH4 oxidation to CH3OH with O2 under mild conditions

Abstract: The selective oxidation of methane, the primary component of natural gas, remains an important challenge in catalysis. We used colloidal gold-palladium nanoparticles, rather than the same nanoparticles supported on titanium oxide, to oxidize methane to methanol with high selectivity (92%) in aqueous solution at mild temperatures. Then, using isotopically labeled oxygen (O2) as an oxidant in the presence of hydrogen peroxide (H2O2), we demonstrated that the resulting methanol incorporated a substantial fraction (70%) of gas-phase O2. More oxygenated products were formed than the amount of H2O2 consumed, suggesting that the controlled breakdown of H2O2 activates methane, which subsequently incorporates molecular oxygen through a radical process. If a source of methyl radicals can be established, then the selective oxidation of methane to methanol using molecular oxygen is possible.

Probes and polymers for optical sensing of oxygen

Abstract: Oxygen detection techniques are used in various fields, such as chemical or clinical analysis and environmental monitoring. Recently, a variety of devices and sensors based on photo-luminescent or photoexcited state quenching of organic dyes have been developed to measure oxygen partial pressure on the solid surface. Many optical oxygen sensors are composed of organic dyes, such as polycyclic aromatic hydrocarbons (pyrene, pyrene derivative etc.), transition metal complexes (Ru2+, Os2+, Ir3+ etc.), metalloporphyrins (Pt2+, Pd2+, Zn2+ etc.) and fullerene (C60 and C70) immobilized in oxygen permeable polymer films. In this review, the properties of various oxygen permeable polymers for matrix of optical oxygen sensor and various dye probes for oxygen sensing are described.

Interaction of black phosphorus with oxygen and water

Abstract: Black phosphorus (BP) has attracted significant interest as a monolayer or few-layer material with extraordinary electrical and optoelectronic properties. Chemical reactions with different ambient species, notably oxygen and water, are important as they govern key properties such as stability in air, electronic structure and charge transport, wetting by aqueous solutions, and so on. Here, we report experiments combined with ab initio calculations that address the effects of oxygen and water in contact with BP. Our results show that the reaction with oxygen is primarily responsible for changing properties of BP. Oxidation involving the dissociative chemisorption of O2 causes the decomposition of BP and continuously lowers the conductance of BP field-effect transistors (FETs). In contrast, BP is stable in contact with deaerated (i.e., O2 depleted) water and the carrier mobility in BP FETs gated by H2O increases significantly due to efficient dielectric screening of scattering centers by the high-k dielectri...

Electrocatalytic Oxygen Reduction Reaction

Abstract: Oxygen (O2) is the most abundant element in the Earth’s crust. The oxygen reduction reaction (ORR) is also the most important reaction in life processes such as biological respiration, and in energy converting systems such as fuel cells. ORR in aqueous solutions occurs mainly by two pathways: the direct 4-electron reduction pathway from O2 to H2O, and the 2-electron reduction pathway from O2 to hydrogen peroxide (H2O2). In non-aqueous aprotic solvents and/or in alkaline solutions, the 1-electron reduction pathway from O2 to superoxide (O2 -) can also occur.