Nitrogen-doped graphene (NG) with wrinkled and bubble-like texture is fabricated by a thermal treatment. Especially, a novel sonication-assisted pretreatment with nitric acid is used to further oxidize graphene oxide and its binding with melamine molecules. There are many bubble-like nanoflakes with a dimension of about 10 nm appeared on the undulated graphene nanosheets. The bubble-like texture provides more active sites for effective ion transport and reversible capacitive behavior. The specific surface area of NG (5.03 at% N) can reach up to 438.7 m g , and the NG electrode demonstrates high specific capacitance (481 F g at 1 A g , four times higher than reduced graphene oxide electrode (127.5 F g )), superior cycle stability (the capacitance retention of 98.9% in 2 m KOH and 99.2% in 1 m H SO after 8000 cycles), and excellent energy density (42.8 Wh kg at power density of 500 W kg in 2 m KOH aqueous electrolyte). The results indicate the potential use of NG as graphene-based electrode material for energy storage devices.

The operating window (OW) is a primary performance criterion for the selective hydrogenation of acetylene in excess ethylene. Currently, most state-of-the-art catalyst systems have an OW of less than 50 °C in front-end processes. Selective acetylene hydrogenation catalysts with an OW wider than 100 °C are rare. Here, we demonstrate a facile stepwise chemical method to synthesize calcite-supported PdBi intermetallic compounds (PdBi/Calcite) that feature isolated and electron-rich Pd atoms as active sites for acetylene hydrogenation. Beneficial from the extremely weak ethylene absorption abilities and the stable structures against the formation of β-PdH x , PdBi/Calcite exhibit >99% selectivity to C 2 H 4 in the whole temperature range tested (50−300 °C) and ∼100% C 2 H 2 conversion from 150 to 300 °C. As a result, an operation window exceeding 150 °C has been achieved.

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Cs–Ce–Zr catalysts with various weight ratios are prepared by the sol–gel method in this paper. The main crystalline phases were identified by X-ray diffraction. The activities of catalysts during soot combustion were tested by thermogravimetric and differential scanning calorimetry. The contact conditions of soot/catalysts (sintered at 450 and 380 °C, respectively, under loose and tight contact conditions) were observed by scanning electron microscopy to study the effect of contact conditions on catalytic activity, and it was determined that the catalytic activities under tight contact conditions are superior to those under loose contact conditions. However, the soot oxidation rate speeds up after the peak temperature of about 450 °C under loose contact conditions, which is due to the fact that the contact condition is enhanced by melting CsNO 3 . The soot onset ignition temperature is lower for the catalysts with more Cs content under loose contact conditions. The minimum gaps of the soot onset ignition temperature and soot oxidation rates under the two contact conditions are 32 and 7 °C, which shows that the gap of catalytic activities under the respective contact conditions can be decreased by the formation of different crystalline phases.

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