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101.
We constructed a fuel‐flexible fuel cell consisting of an alkaline anion exchange membrane, palladium anode, and platinum cathode. When an alcohol fuel was used with potassium hydroxide added to the fuel stream and oxygen was the oxidant, the following maximum power densities were achieved at 60 °C: ethanol (128 mW cm−2), 1‐propanol (101 mW cm−2), 2‐propanol (40 mW cm−2), ethylene glycol (117 mW cm−2), glycerol (78 mW cm−2), and propylene glycol (75 mW cm−2). We also observed a maximum power density of 302 mW cm−2 when potassium formate was used as the fuel under the same conditions. However, when potassium hydroxide was removed from the fuel stream, the maximum power density with ethanol decreased to 9 mW cm−2 (using oxygen as oxidant), while with formate it only decreased to 120 mW cm−2 (using air as the oxidant). Variations in the performance of each fuel are discussed. This fuel‐flexible fuel cell configuration is promising for a number of alcohol fuels. It is especially promising with potassium formate, since it does not require hydroxide added to the fuel stream for efficient operation. 相似文献
102.
Strawberry is a non-climacteric fruit, with low ethylene production rate after harvest. Its response to nitric oxide (NO), which can be released from sodium nitroprusside (SNP), was studied. We have examined the effect of 1.0, 5.0 and 10.0 μmol l−1 SNP aqueous solution on ethylene production, respiration rate, 1-aminocyclopropane-1-carboxylic acid (ACC) content and the activities of ACC synthase and ACC oxidase in post-harvest strawberry (“Fengxiang”). The most remarkable effect was obtained with 5 μmol l−1 SNP aqueous solution, which significantly inhibited ethylene production, respiration rate, the activity of ACC synthase and reduced the content of ACC, but did not significantly affect the activity of ACC oxidase. SNP at 10 μmol l−1 harmed the fruits; 1 μmol l−1 SNP was too low to significantly extend strawberry storage life. It was suggested that NO could decrease ethylene output, through inhibiting ACC synthase activity reducing ACC content. 相似文献
103.
乙烯基硅氧烷单体接枝家蚕丝的性能研究 总被引:1,自引:1,他引:1
采用新型乙烯基硅氧烷单体对家蚕丝接枝改性,通过红外光谱和扫描电镜分析,接枝单体足依靠物理沉积和化学键作用与纤维结合的。接枝后真丝织物的折皱回复性显著提高,手感更为柔软,且小影响家蚕丝的强度。接枝后家蚕丝的白度和染色性略有下下降,染色色牢度与未处理真丝织物基本相同。 相似文献
104.
Jing-Jing Lv Shan-Shan LiJie-Ning Zheng Ai-Jun WangJiu-Ju Feng 《International Journal of Hydrogen Energy》2014
In this work, a simple and facile method is developed in the synthesis of well-dispersed PtAg nanoflowers on reduced graphene oxide nanosheets (PtAg/RGOs) under solvothermal conditions, using ethylene glycol as a reducing agent and hexadecyl trimethyl ammonium bromide (CTAB) as capping and stabilizing agents. The as-prepared nanocomposites show a superior electrocatalytic activity, good tolerance, and better stability toward the oxidation of formic acid and ethylene glycol in alkaline media, compared with the commercial Pt/C (10 wt%) catalyst. For the oxidation of formic acid, the PtAg nanoflowers own thirty times higher of the catalytic currents than those of the commercial Pt/C catalyst. Meanwhile, for the oxidation of ethylene glycol, the ratio of forward current (jF) to reverse current (jR) is high up to 8.4, which is almost four times higher than that of the commercial Pt/C catalyst. This strategy provides a promising platform for direct formic acid and ethylene glycol fuel cells. 相似文献
105.
Isotopic transient tracer techniques have been employed to study heterogeneous hydroformylation on Rh/SiO2 and Mn–Rh/SiO2. Pulse injection of D2 and
allowed tracing of the deuterium and CO incorporation pathway into the aldehyde product. The d1- and d2-propionaldehyde responses showed a double-peak, or two-hump, response to the D2 pulse, while
showed a single-hump response to the
pulse. Analysis of the product responses to the D2 pulse in CO/H2/C2H4 and CO/H2/C2H4/C2H5CHO suggests that the first hump of the d1- and d2-propionaldehyde responses was due to rapid H/D exchange with adsorbed propionaldehyde via enol intermediates. The decay of the second hump was due to reaction of adsorbed acyl with spillover hydrogen/deuterium. The
response was due to CO insertion followed by acyl hydrogenation. Compartment modeling of the product responses from the
and D2 pulse inputs allowed determination of residence times of adsorbed intermediates, surface coverages of adsorbed intermediates, and the elementary rate constants for acyl hydrogenation and CO insertion. Elementary rate constants for acyl hydrogenation determined from this study were consistent with the value calculated by transition state theory (TST). The addition of Mn promoter to Rh/SiO2 increased coverages of
,
, and
and shifted the rate-limiting step for propionaldehyde formation. Acyl hydrogenation is the rate-limiting step on Rh/SiO2 while CO insertion and acyl hydrogenation are both kinetically significant on Mn–Rh/SiO2. 相似文献
106.
介绍了环氧乙烷羰基合成1,3-丙二醇过程中的化学特性;考察了不同催化剂组合物配方对反应结果的影响,并对反应产物作了较尽尽的定性分析。 相似文献
107.
Functionalized siloxane-based solid polymer electrolytes were synthesized using a platinum-catalyzed silylation reaction.
The ionic conductivities of these solid polymer electrolytes were measured as a function of the concentration of lithium bis(trifluoromethylsulfonyl)imide
(LiTFSi) salt. The highest ionic conductivity and lowest activation energy of solid polymer electrolytes were observed to
be 1.15 × 10−4 S cm−1 (25 °C) and 3.85 kJ mol−1, respectively. The interface property between electrolyte and electrode and thermal stability of the polymer electrolytes
were found to enhance after they were functionalized with acrylate, and the functionalized electrolytes were observed to maintain
a glass transition temperature as low as that of other siloxane compounds. Thus, modifications involving acrylate with ethylene
oxide group substitution provide a route for carrier ions and enhance both the ionic conductivity and mechanical properties
of the siloxane structure. 相似文献
108.
Andreas Peschel Florian Karst Hannsjörg Freund Kai Sundmacher 《Chemical engineering science》2011,(24):6453
In this work, a recently proposed multi-level reactor design methodology (Peschel et al., 2010) is extended and applied for the optimal design of an ethylene oxide reactor. In a first step, the optimal reaction route is calculated taking various process intensification concepts into account. The potential of each reaction concept can be efficiently quantified, which is the economic basis for the design of advanced reactors. Based on these results, a promising concept is further investigated and a technical reactor is designed. As an extension to the design method, reactor design criteria for external and internal heat and mass transfer limitations are directly included in the optimization approach in order to design the catalyst packing. The derived reactor concept is investigated with a detailed 2D reactor model accounting for radial concentration and temperature gradients in addition to a radial velocity profile.The example considered in this work is the production of ethylene oxide which is one of the most important bulk chemicals. Due to the high ethylene costs, the selectivity is the main factor for the economics of the process. A membrane reactor with an advanced cooling strategy is proposed as best technical reactor. With this reactor design it is possible to increase the selectivity of the ethylene epoxidation by approximately 3% compared to an optimized reference case. 相似文献
109.
Very high ethylene selectivity values approaching 100% and very high ethanol conversion values approaching 85% were obtained in dehydration of ethanol over a new W-silicate-based nanocomposite catalyst having both meso and macropores and containing a W/Si atomic ratio of 0.85. Silicotungsticacid was successfully incorporated into the catalyst structure following a one-pot hydrothermal synthesis procedure. This catalyst is highly stable and does not loose activity in polar solvents and it has a sufficiently high surface area for catalytic applications. Calcination temperature of the catalyst was found to have a very significant effect on the catalyst structure and also on its catalytic performance in ethanol dehydration. Maximum selectivity of the second major reaction product diethylether was obtained as 0.7 at 200 °C, with the catalyst which was calcined at 400 °C. Very high ethylene and diethylether yield values obtained in this study at different reaction conditions are highly promising for the production of petrochemicals from ethanol. 相似文献
110.