2 research outputs found
Carbon-Free CoO Mesoporous Nanowire Array Cathode for High-Performance Aprotic Li–O<sub>2</sub> Batteries
Although
various kinds of catalysts have been developed for aprotic
Li–O<sub>2</sub> battery application, the carbon-based cathodes
are still vulnerable to attacks from the discharge intermediates or
products, as well as the accompanying electrolyte decomposition. To
ameliorate this problem, the free-standing and carbon-free CoO nanowire
array cathode was purposely designed for Li–O<sub>2</sub> batteries.
The single CoO nanowire formed as a special mesoporous structure,
owing even comparable specific surface area and pore volume to the
typical Super-P carbon particles. In addition to the highly selective
oxygen reduction/evolution reactions catalytic activity of CoO cathodes,
both excellent discharge specific capacity and cycling efficiency
of Li–O<sub>2</sub> batteries were obtained, with 4888 mAh
g<sub>CoO</sub><sup>–1</sup> and 50 cycles during 500 h period.
Owing to the synergistic effect between elaborate porous structure
and selective intermediate absorption on CoO crystal, a unique bimodal
growth phenomenon of discharge products was occasionally observed,
which further offers a novel mechanism to control the formation/decomposition
morphology of discharge products in nanoscale. This research work
is believed to shed light on the future development of high-performance
aprotic Li–O<sub>2</sub> batteries
Irregularities in Product Distribution of Fischer–Tropsch Synthesis Due to Experimental Artifact
Experimental product distribution of Fischer–Tropsch
synthesis frequently presents notable deviations from the typical
double-α Anderson–Schulz–Flory pattern: bump or
dip around the breaking carbon number, positive or negative deviation
for heavy hydrocarbons. These irregularities were studied experimentally
in a fixed-bed reactor over an industrial Fe/Mn catalyst, and theoretically
by a product separation model based on Aspen Plus software. First,
it was found that the unsteady state of reaction condition or improper
gas chromatograph procedure could lead to deviation for heavy hydrocarbon
distribution. Second, the bump near the breaking carbon number could
be attributed to the accumulation of water in hot trap, which leads
to an inaccurate measurement of the wax amount. This irregularity
can be eliminated by selecting either a higher temperature or a lower
pressure of the hot trap. Third, vaporization or flash loss of the
oil sample during product collection could result in dip in light
hydrocarbon distribution. High syngas conversion levels should be
avoided for accurate data acquirement