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  1. Experiment and microkinetic modeling decouple the synergistic roles of La 1−x Sr x CoO 3−δ perovskite oxides and carbon additives during the oxygen reduction reaction.
  2. The key to understanding the cycling mechanism of lithium-ion battery electrodes is to develop methods to monitor the dynamic cell chemistry, but the complexity of the problem has continued to pose an obstacle.
  3. A type of benzoquinone-derived porous organic polymer with hydrophenazine linkages, porous hydrophenazine frameworks, has been developed.
  4. Porous carbons with different textural properties exhibit great differences in CO 2 adsorption capacity. It is generally known that narrow micropores contribute to higher CO 2 adsorption capacity. However, it is still unclear what role each variable in the textural properties plays in CO 2 adsorption. Herein, a deep neural network is trained as a generative model to direct the relationship between CO 2 adsorption of porous carbons and corresponding textural properties. The trained neural network is further employed as an implicit model to estimate its ability to predict the CO 2 adsorption capacity of unknown porous carbons. Interestingly, themore » practical CO 2 adsorption amounts are in good agreement with predicted values using surface area, micropore and mesopore volumes as the input values simultaneously. This unprecedented deep learning neural network (DNN) approach, a type of machine learning algorithm, exhibits great potential to predict gas adsorption and guide the development of next-generation carbons.« less
  5. Here, a simple and versatile strategy, borrowing ideas from the chemistry of MOFs and COFs, is developed for the synthesis of coordination-supported organic polymers (COPs) via coordination between Al 3+ and 5-amino-8-hydroxyquinoline together with organic imine- or imide-based polycondensation. The COPs with high surface areas (up to 1123 m 2 g -1) and abundant mesopores (2.5 nm or 14 nm) possess good crystalline and porous structure after being soaked in boiling water.
  6. Pore density is an important factor dictating gas separations through one-atom-thin nanoporous membranes, but how it influences the gas permeation is not fully understood. We use molecular dynamics (MD) simulations to investigate gas permeation through nanoporous graphene membranes with the same pore size (3.0 Å × 3.8 Å in dimensions) but varying pore densities (from 0.01 to 1.28 nm -2). We find that higher pore density leads to higher permeation per unit area of membrane for both CO 2 and He, but the rate of the increase decreases greatly for CO 2 at high pore densities. As a result, themore » per-pore permeance decreases for CO 2 but remains relatively constant for He with the pore density, leading to a dramatic change in CO 2/He selectivity. By separating the total flux into direct flux and surface flux, we find that He permeation is dominated by direct flux and hence the per-pore permeation rate is roughly constant with the pore density. In contrast, CO 2 permeation is dominated by surface flux and the overall decreasing trend of the per-pore permeation rate of CO 2 with the pore density can be explained by the decreasing per-pore coverage of CO 2 on the feed side with the pore density. Finally, our work now provides a complete picture of the pore-density dependence of gas permeation through one-atom-thin nanoporous membranes.« less
  7. A dual-template strategy for facile preparation of a bifunctional oxygen electrocatalyst for high-performance rechargeable zinc–air batteries has been reported.
  8. Zeolite materials play a significant role throughout the oil refining and petrochemical industry. Microporous ZSM-5 has a high degree of crystallinity but low mass transfer, while hierarchical ZSM-5 shows a low degree of crystallinity as well as acidity. Here, we first report the synthesis of ZSM-5 with a new morphological structure, which has nanocrystalline ZSM-5 particles on the surface of an intact ZSM-5 zeolite. This not only improved the mass transfer in microporosity but also overcame disadvantages of hierarchical ZSM-5 including low degrees of crystallinity and acidity. This new and very efficient structure with both intracrystal microporosity and intercrystal macroporosity,more » formed by secondary crystallization after the intact ZSM-5 zeolite was synthesized, was verified by transmission electronic microscopy, N 2 adsorption and desorption, and X-ray diffraction. Lastly, the obtained ZSM-5 zeolite showed a uniform size (~200 nm), high crystallinity acidity, and a suitable hierarchical structure that exhibited excellent properties in the catalytic fast pyrolysis of cellulose to produce aromatics.« less
  9. Tin and tin oxide-based electrodes are promising high-capacity anodes for lithium-ion batteries. However, poor capacity retention is the major issue with these materials due to the large volumetric expansion that occurs when lithium is alloyed with tin during lithiation and delithiation process. Here, a method to prepare a low-cost, scalable carbon and tin(II) oxide composite anode is reported. The composite material was prepared by ball milling of carbon recovered from used tire powders with 25 wt% tin(II) oxide to form lithium-ion battery anode. With the impact of energy from the ball milling, tin oxide powders were uniformly distributed inside themore » pores of waste-tire-derived carbon. During lithiation and delithiation, the carbon matrix can effectively absorb the volume expansion caused by tin, thereby minimizing pulverization and capacity fade of the electrodes. In conclusion, the as-synthesized anode yielded a capacity of 690 mAh g –1 after 300 cycles at a current density of 40 mA g –1 with a stable battery performance.« less

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