Parameters Optimization of Catalytic Tubular Nanomembrane-Based Oxygen Microbubble Generator

A controllable generation of oxygen gas during the decomposition of hydrogen peroxide by the microreactors made of tubular catalytic nanomembranes has recently attracted considerable attention. Catalytic microtubes play simultaneous roles of the oxygen bubble producing microreactors and oxygen bubble-driven micropumps. An autonomous pumping of peroxide fuel takes place through the microtubes by the recoiling microbubbles. Due to optimal reaction–diffusion processes, gas supersaturation, leading to favorable bubble nucleation conditions, strain-engineered catalytic microtubes with longer length produce oxygen microbubbles at concentrations of hydrogen peroxide in approximately ×1000 lower in comparison to shorter tubes. Dynamic regimes of tubular nanomembrane-based oxygen microbubble generators reveal that this depends on microtubes’ aspect ratio, hydrogen peroxide fuel concentration and fuel compositions. Different dynamic regimes exist, which produce specific bubble frequencies, bubble size and various amounts of oxygen. In this study, the rolled-up Ti/Cr/Pd microtubes integrated on silicon substrate are used to study oxygen evolution in different concentrations of hydrogen peroxide and surfactants. Addition of Sodium dodecyl sulfate (SDS) surfactants leads to a decrease of bubble diameter and an increase of frequencies of bubble recoil. Moreover, an increase of temperature (from 10 to 35 °C) leads to higher frequencies of oxygen bubbles and larger total volumes of produced oxygen

Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co₃O₄ Nanostructures for Lithium Ion Battery Anode Materials

We report a facile synthesis of a novel cobalt oxide (Co(3)O(4)) hierarchical nanostructure, in which crystalline core-amorphous shell Co(3)O(4) nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co(3)O(4) nanosheets. When tested as anode materials for lithium ion batteries, the as-prepared Co(3)O(4) hierarchical electrodes delivered high lithium storage properties comparing to the other Co(3)O(4) nanostructures, including a high reversible capacity of 1053.1 mAhg(−1) after 50 cycles at a current density of 0.2 C (1 C = 890 mAg(−1)), good cycling stability and rate capability