I had a super chill weekend where I didn’t have work standing on my neck for once and basically had to be pried out of bed with a crowbar to draw something in time for this update hahaha
Yup. He really did.
A selective, metal-free generation of α-carbonyl cations from simple internal alkynes was accomplished by addition of a sulfoxide to a congested vinyl cation. The high reactivity of the thus generated α-carbonyl cations was found to efficiently induce hydrogen- and even carbon shift reactions with unusual selecivities. Thereby, complex and highly congested tertiary and quartenary, all-carbon-substituted centers are accessed in a single step from simple precursors. Mechanistic analysis strongly supports the intermediacy of the title species and provides a simple predictive scheme for the migratory aptitude of different substituents.
In Situ Fabrication of Ni–Mo Bimetal Sulfide Hybrid as an Efficient Electrocatalyst for Hydrogen Evolution over a Wide pH Range
Chiral Thioureas Promote Enantioselective Pictet–Spengler Cyclization by Stabilizing Every Intermediate and Transition State in the Carboxylic Acid-Catalyzed Reaction
After 16 years in Afghanistan, the U.S. can neither declare victory nor disengage. So the president calls for more troops, more time, more sacrifice — with no way of knowing how much might be enough.
(Image credit: Mark Wilson/Getty Images)
Sodium-ion batteries (SIBs) are considered as promising alternatives to lithium-ion batteries (LIBs) for large-scale electrical-energy-storage applications due to the wide availability and the low cost of Na resources. Along with the avenues of research on flexible LIBs, flexible SIBs are now being actively developed as one of the most promising power sources for the emerging field of flexible and wearable electronic devices. Here, the recent progress on flexible electrodes based on metal substrates, carbonaceous substrates (i.e., graphene, carbon cloth, and carbon nanofibers), and other materials, as well as their applications in flexible SIBs, are summarized. Also, some future research directions for constructing flexible SIBs are proposed, with the aim of providing inspiration to the further development of advanced flexible SIBs.
Flexible sodium-ion batteries (SIBs) are being actively developed as one of the most promising power sources for the emerging field of flexible and wearable electronic devices. The recent progress on flexible electrodes based on metal substrates, carbonaceous substrates, and other materials, is summarized, along with their applications in flexible SIBs.
Highly Efficient Nondoped OLEDs with Negligible Efficiency Roll-Off Fabricated from Aggregation-Induced Delayed Fluorescence Luminogens
Pure organic emitters that can efficiently utilize triplet excitons are highly desired to cut cost of organic light-emitting diodes (OLEDs), but most of them require complicated doping technique and suffer from severe efficiency roll-off. Herein, we develop novel luminogens exhibiting weak emissions with inconspicuous and negligible delayed fluorescence in solutions but strong emissions with prominent delayed components in aggregates, presenting intriguing aggregation-induced delayed fluorescence (AIDF) feature. The concentration-caused emission quenching and exciton annihilation are well-suppressed, rendering high emission efficiencies and efficient exciton utilization in neat films. Their nondoped OLEDs provide excellent electroluminescence efficiencies of 59.1 cd A‒1, 65.7 lm W‒1 and 18.4%, and negligible current efficiency roll-off of 1.2% at 1000 cd m‒2. Exploring AIDF luminogens to construct nondoped OLEDs could be a promising strategy to advance device efficiency and stability.
DOI: 10.1039/C7CS00391A, Review Article
Principles rooted in supramolecular chemistry have empowered new and highly functional therapeutics and drug delivery devices. This general approach offers elegant tools rooted in molecular and materials engineered to address the many challenges faced in treating disease.
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A High-Volumetric-Capacity Cathode Based on Interconnected Close-Packed N-Doped Porous Carbon Nanospheres for Long-Life Lithium–Sulfur Batteries
This study reports a Li–S battery cathode of high volumetric capacity enabled by novel micro- and mesostructuring. The cathode is based on monodisperse highly porous carbon nanospheres derived from a facile template- and surfactant-free method. At the mesoscale, the nanospheres structure into interconnected close-packed clusters of a few microns in extent, thus facilitating the fabrication of dense crack-free high areal sulfur loading (5 mg cm−2) cathodes with high electrical conductivity and low cathode impedance. A combination of the nitrogen doping (5 wt%), high porosity (2.3 cm3 g−1), and surface area (2900 m2 g−1) at the microscale enables high sulfur immobilization and utilization. The cathode delivers among the best reported volumetric capacity to date, above typical Li-ion areal capacity at 0.2 C over 200 cycles and low capacity fading of 0.1% per cycle at 0.5 C over 500 cycles. The compact cathode structure also ensures a low electrolyte requirement (6 µL mg−1), which aids a low overall cell weight, and further, among the best gravimetric capacities published to date as well.
Li–S battery cathodes providing among the best volumetric/gravimetric capacities reported to date are prepared using interconnected close-packed N-doped carbon nanospheres of high surface area and porosity. The novel close-packed mesostructure and N-doped highly porous microstructure enable simultaneously high sulfur density and utilization, excellent electrochemical impedance, long cycle-life, and low electrolyte fraction, which all-together leads to the outstanding volumetric/gravimetric capacities.
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I take it back. I would buy this in a heartbeat.
Hey geeks of Houston! We've sold more than half of the discounted student tickets for BAHFest Houston! Buy soon if you wanna see me, Jorge Cham, Phil Plait, and lady-who-went-to-freakin-space Nicole Stott.
Three-dimensional architectures constructed from transition metal dichalcogenide nanomaterials for electrochemical energy storage and conversion
Transition metal dichalcogenides (TMDs) have attracted considerable attention in recent years due to their unique properties and promising applications in electrochemical energy storage and conversion. However, the limited number of active sites and blocked ion and mass transport severely impair the electrochemical performance of TMDs. Construction of three-dimensional (3D) architectures from TMD nanomaterials has been proven an effective strategy to solve the aforementioned problems due to their large specific surface area and short ion and mass transport distance. Here, we summarize the commonly used routes to build 3D TMD architectures and highlight their applications in electrochemical energy storage and conversion, including batteries, supercapacitors, and electrocatalytic hydrogen evolution. Moreover, the challenges and outlooks in this research area are also discussed.
Defective and “c-Disordered” Hortensia-like Layered MnOx as an Efficient Electrocatalyst for Water Oxidation at Neutral pH
The Chemistry of CO2 Capture in an Amine-Functionalized Metal–Organic Framework under Dry and Humid Conditions
A general polymer-assisted strategy enables unexpected efficient metal-free oxygen-evolution catalysis on pure carbon nanotubes
DOI: 10.1039/C7EE01702B, Communication
A conceptually-new and general strategy was, for the first time, proposed to significantly boost the electrocatalytic activity of metal-free pure carbon nanotubes (CNTs) towards oxygen evolution reaction (OER) by simple...
The content of this RSS Feed (c) The Royal Society of Chemistry
I was not prepared for how incredible the total eclipse was. It was, literally, awesome. Almost a spiritual experience. I also did not anticipate the crazy-ass, reverse storm-chasing car ride we’d need to undertake in order to see it.
I’m not a bucket list sort of person, but ever since seeing a partial eclipse back in college in the 90s (probably this one), I have wanted to witness a total solar eclipse with my own eyes. I started planning for the 2017 event three years ago…the original idea was to go to Oregon, but then some college friends suggested meeting up in Nebraska, which seemed ideal: perhaps less traffic than Oregon, better weather, and more ways to drive in case of poor weather.
Well, two of those things were true. Waking up on Monday, the cloud cover report for Lincoln didn’t look so promising. Rejecting the promise of slightly better skies to the west along I-80, we opted instead to head southeast towards St. Joseph, Missouri where the cloud cover report looked much better. Along the way, thunderstorms started popping up right where we were headed. Committed to our route and trusting this rando internet weather report with religious conviction, we pressed on. We drove through three rainstorms, our car hydroplaning because it was raining so hard, flood warnings popping up on our phones for tiny towns we were about to drive through. Moral was low and the car was pretty quiet for awhile; I Stoically resigned myself to missing the eclipse.
But on the radar, hope. The storms were headed off to the northeast and it appeared as though we might make it past them in time. The Sun appeared briefly through the clouds and from the passenger seat, I stabbed at it shining through the windshield, “There it is! There’s the Sun!” We angled back to the west slightly and, after 3.5 hours in the car, we pulled off the road near the aptly named town of Rayville with 40 minutes until totality, mostly clear skies above us. After our effort, all that was missing was a majestic choral “ahhhhhh” sound as the storm clouds parted to reveal the Sun.
My friend Mouser got his camera set up — he’d brought along the 500mm telephoto lens he uses for birding — and we spent some time looking at the partial eclipse through our glasses, binoculars (outfitted with my homemade solar filter), and phone cameras. I hadn’t seen a partial eclipse since that one back in the 90s, and it was cool seeing the Sun appear as a crescent in the sky. I took this photo through the clouds:
Some more substantial clouds were approaching but not quickly enough to ruin the eclipse. I pumped my fist, incredulous and thrilled that our effort was going to pay off. As totality approached, the sky got darker, our shadows sharpened, insects started making noise, and disoriented birds quieted. The air cooled and it even started to get a little foggy because of the rapid temperature change.
We saw the Baily’s beads and the diamond ring effect. And then…sorry, words are insufficient here. When the Moon finally slipped completely in front of the Sun and the sky went dark, I don’t even know how to describe it. The world stopped and time with it. During totality, Mouser took the photo at the top of the page. I’d seen photos like that before but had assumed that the beautifully wispy corona had been enhanced with filters in Photoshop. But no…that is actually what it looks like in the sky when viewing it with the naked eye (albeit smaller). Hands down, it was the most incredible natural event I’ve ever seen.
After two minutes — or was it several hours? — it was over and we struggled to talk to each other about what we had just seen. We stumbled around, dazed. I felt high, euphoric. Raza Syed put it perfectly:
It was beautiful and dramatic and overwhelming — the most thrillingly disorienting passage of time I’ve experienced since that one time I skydived. It was a complete circadian mindfuck.
After waiting for more than 20 years, I’m so glad I finally got to witness a total solar eclipse in person. What a thing. What a wondrous thing.Tags: 2017 solar eclipse astronomy Moon Mouser Williams photography Raza Syed science Sun travel
Macroscopic-Scale Three-Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices
The development of high-performance electrochemical energy storage devices is critical for addressing energy crises and environmental pollution. Hence, the design and preparation of next-generation electrode materials have been gaining increasing attention. Recent progress has demonstrated that three-dimensional (3D) carbon nanomaterials are extremely promising candidates for the electrodes of electrochemical energy storage devices due to their unique structural advantages of interlinked architecture. Herein, recent advances in the scalable fabrication of 3D carbon nanofiber (CNF)-based materials and their applications for electrochemical energy storage devices are summarized. Some representational 3D CNF architectures, such as CNF gels, 3D CNF films, 3D CNF arrays, and their nanocomposites, are highlighted with regard to various applications, including supercapacitors, lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), lithium–sulfur (Li–S), lithium–selenium (Li–Se), and metal–O2 batteries, as well as other new battery systems. Finally, contemporary challenges in the scalable fabrication of 3D CNF architectures are outlined and a brief outlook to future studies is given. This review illustrates significant opportunities for the macroscopic fabrication of 3D CNF architectures, and therefore inspires new discoveries to promote the practical applications of 3D CNF architectures in electrochemical energy storage fields.
High-performance electrochemical energy storage devices are essential; therefore, the design and preparation of next-generation electrode materials have gained increasing attention. Three-dimensional (3D) carbon nanofiber (CNF)-based materials are promising electrode materials, and thus their scalable fabrication and application in electrochemical energy storage devices are summarized, alongside current challenges and future studies.