Overcoming limitations in propane dehydrogenation by codesigning catalyst-membrane systems.

Propylene production through propane dehydrogenation (PDH) is endothermic, and high temperatures required to achieve acceptable propane conversions lead to low selectivity and severe carbon-induced deactivation of conventional catalysts. We developed a catalyst-membrane system that removes the hydrogen by-product and can thus achieve propane conversions that exceed equilibrium limits. In this codesigned system, a silica/alumina (SiO/AlO) hollow-fiber hydrogen membrane was packed with a selective platinum-tin (PtSn/SiO) PDH catalyst on the tube side with hydrogen diffusing from the tube to the shell side.

Optimizing hierarchical membrane/catalyst systems for oxidative coupling of methane using additive manufacturing.

The advantage of a membrane/catalyst system in the oxidative coupling of methane compared with conventional reactive systems is that by introducing oxygen into the catalytic sites through a membrane, the parasitic gas-phase reactions of O(g)-responsible for lowering product selectivity-can be avoided. The design and fabrication of membrane/catalyst systems has, however, been hampered by low volumetric chemical conversion rates, high capital cost and difficulties in co-designing membrane and catalyst properties to optimize the performance. Here we solve these issues by developing a dual-layer additive manufacturing process, based on phase inversion, to design, fabricate and optimize a hollow-fibre membrane/catalyst system for the oxidative coupling of methane.

Stable and selective catalysts for propane dehydrogenation operating at thermodynamic limit.

Intentional ("on-purpose") propylene production through nonoxidative propane dehydrogenation (PDH) holds great promise for meeting the increasing global demand for propylene. For stable performance, traditional alumina-supported platinum-based catalysts require excess tin and feed dilution with hydrogen; however, this reduces per-pass propylene conversion and thus lowers catalyst productivity. We report that silica-supported platinum-tin (PtSn) nanoparticles (<2 nanometers in diameter) can operate as a PDH catalyst at thermodynamically limited conversion levels, with excellent stability and selectivity to propylene (>99%).

Atomistic Simulation Derived Insight on the Irreversible Structural Changes of Si Electrode during Fast and Slow Delithiation.

Quantifying the irreversible chemical and structural changes of Si during cycling remains challenging. In this study, a continuous reactive molecular dynamics delithiation algorithm, with well-controlled potential gradient and delithiation rate, was developed and used to investigate the "natural" delithiation responses of an aluminum-oxide coated silicon thin-film. Fast delithiation led to the formation of dense Si network near the surface and nanoporosity inside the a-LiSi, resulting in 141% volume dilation and significant amount of Li trapped inside (a-LiSi) at the end of delithiation process.

Oolichan grease: a unique marine lipid and dietary staple of the north Pacific coast.

Oolichan grease, a dietary fat prepared from smelt-like fish, is highly prized by north Pacific coast aboriginal cultures. The composition of oolichan grease is unclear, with one report indicating a high 22:6n-3 content consistent with cold-water marine oils, but another reporting a much lower value. We noted that oolichan grease remains solid up to 15 degrees C, suggesting a low polyunsaturate content.

Low-carbohydrate nutrition and metabolism.

The persistence of an epidemic of obesity and type 2 diabetes suggests that new nutritional strategies are needed if the epidemic is to be overcome. A promising nutritional approach suggested by this thematic review is carbohydrate restriction. Recent studies show that, under conditions of carbohydrate restriction, fuel sources shift from glucose and fatty acids to fatty acids and ketones, and that ad libitum-fed carbohydrate-restricted diets lead to appetite reduction, weight loss, and improvement in surrogate markers of cardiovascular disease.