several limiting factors can weigh heavily against the overall performance before the MFC technology can gain a signifi cant share of energy market. In particular, the power generated from MFC is commonly limited by the cathode poor performance owing to kinetic sluggishness of cathodic oxygen reduction reaction (ORR) in pHneutral aqueous electrolyte. [ 2 ] The ORR takes place through twoelectron (H 2 O 2 ) or four-electron (H 2 O) pathway depending on the electrocatalyst and electrolyte used. To maximize power density and energy conversion of MFC, the four-electron ORR process is necessary. This gives priority to explore highly active electrocatalyst toward four-electron ORR under pH-neutral condition. [ 2b , 3 ] Much effort has been devoted to enhance the cathode performance by either exploring available electrocatalyst, such as noble metals, nitrogen-doped carbonaceous materials and transition metal or metal oxides, or optimizing the property of three-phase boundary where oxygen reacts with electron and proton to form water. [ 4 ] However, there still exist several challenges for the carbonsupported particle-structured electrocatalysts in MFC, due to the occurrence of migration and agglomeration of catalyst particles at "water-fl ooding" three-phase boundary. [ 2b ] Inevitably, this will cause the loss of electrochemically active surface area for mass transfer of protons and oxygen, and thus the decrease in the activity, selectivity, and stability of the electrocatalyst. [ 5 ] Meanwhile, despite the best performance of platinum catalyst observed hitherto, the high cost and scarcity of platinum constitute the obstacle in the drive for scale-up applications. [ 2b , 6 ] Therefore, developing an inexpensive electrocatalyst with nonparticulate defi ned 3D porous structure, large surface area, and abundant active sites for effi cient cathodic oxygen reduction in MFC is still highly desirable.Metal-organic frameworks (MOFs), which consist of metal ions (clusters) and organic ligands, have a highly defi ned 3D network structure at molecular level. [ 7 ] Given their unique properties of high surface area, tunable porous structures, and uniform open cavities, [ 8 ] MOFs have attracted growing interest in potential applications in many areas, such as gas storage and Microbial fuel cell (MFC) can generate electricity from organic substances based on anodic electrochemically active microorganisms and cathodic oxygen reduction reaction (ORR), thus exhibiting promising potential for harvesting electric energy from organic wastewater. The ORR performance is crucial to both power production effi ciency and overall cost of MFC. A new type of metal-organic-framework-derived electrocatalysts containing cobalt and nitrogen-doped carbon (CoNC) is developed, which is effective to enhance activity, selectivity, and stability toward four-electron ORR in pH-neutral electrolyte. When glucose is used as the substrate, the maximum power density of 1665 mW m −2 is achieved for the optimized CoNC pyrolyzed at 900 °C, which is 39.8...

Hydration of poly(butadiene-b-ethylene oxide) diblock copolymers leads to various ordered and disordered phases, analogous to the aqueous phase behavior of surfactants and lipids. Small-angle x-ray scattering measurements corroborated by cryogenic scanning electron microscopy imaging reveal a random network (N) morphology at polymer compositions and water content intermediate to those associated with ordered cylinders (H1) and lamellae (L). This sequence of self-assembled structures is strikingly similar to the phase behavior of certain water-oil-surfactant microemulsions.

A bioinspired active anode with a suction effect is demonstrated for microbial fuel cells by constructing polypyrrole (PPy) nanotubular arrays on carbon textiles. The oxygen in the inner space of the nanosucker can be depleted by micro-organisms with the capability of facul-tative respiration, forming a vacuum, which then activates the electrode to draw the microorganism by suction and thus improve the bioelectricity generation.

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The phase behavior of poly(ethylene oxide)-poly(butadiene) (PEO-PB) diblock copolymers mixed with water was studied using small-angle X-ray scattering (SAXS), cryogenic scanning electron microscopy (cryo-SEM), cryogenic transmission electron microscopy (cryo-TEM), and dynamic mechanical spectroscopy. Two sets of diblocks were synthesized by adding different lengths of PEO to hydroxy terminated PB with degrees of polymerization N PB ) 46 and 170. Two-component mixtures were investigated as a function of block composition and copolymer molecular weight, between 1 and 100 wt % polymer content. Melt phase behavior is consistent with established theory and known experimental behavior for diblock copolymers. Various lyotropic liquid crystalline structures, notably lamellae (L), hexagonally packed cylinders (H), and spheres (S) arranged on cubic (body-centered cubic, face-centered cubic) lattices, were documented as a function of water content. At the higher molecular weights (N PB ) 170), a random network phase (N) was identified over a sizable portion of the phase portrait, located between hexagonally ordered cylinders and ordered lamellae. This new structure, along with branching of cylindrical micelles in the dilute limit, bear a striking similarity to experimentally observed and theoretically predicted phase behavior in certain ternary water/oil/surfactant systems. These findings demonstrate that block copolymer surfactants are characterized by at least four structural building blocks-spheres, cylinders, bilayers, and branched cylinders-above a threshold molecular weight.

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Macroscopic three-dimensional NF/ZIF-67 efficiently catalyzed peroxymonosulfate activation.