Qilei Yang,Ang Cao,Na Kang,Hongyan Ning,Jiaming Wang,Zhao-Tie Liu,Yuan Liu
The catalytic performance of Cu–Co/Al2O3 in the slurry reactor for direct ethanol synthesis from syngas was investigated. The reduced catalyst and catalyst reacted for 100, 300, 500, and 750 h were characterized by using XRD, TEM, EDS, BET, and ICP-MS techniques. Compared with that in the fixed-bed reactor, the catalyst in the slurry reactor exhibited higher selectivity to ethanol, which was above 70 wt % in the total alcohols. The structure variation of the bimetallic Cu–Co with reaction time is that CuCo2O4 was transformed into Cu–Co alloy after reduction, and Cu–Co alloy was decomposed into Cu and Co after reaction for 100 h. After reaction for 300 h, Co2C started to generate and Cu@Co@Co2C was formed as reacted for 500 h. All of Cu–Co alloy, Cu@Co, and Cu@Co@Co2C are highly selective to ethanol, which was maintained for 750 h. Meanwhile, the slurry solvent of PEG-400 is another reason for the high ethanol selectivity.
Juan Du,Jiaren Zhang,Yong Sun,Wenlong Jia,Zhihao Si,He Gao,Xing Tang,Xianhai Zeng,Tingzhou Lei,Shijie Liu,Lu Lin
Catalytic transfer hydrogenation (CTH) of bio-derived furfural (FF) to furfuryl alcohol (FFA) was performed using the physically mixed CuO-Pd/C as catalyst and formic acid (FA) as hydrogen donor. The evolution investigation of Cu showed the precursor CuO firstly dissolved into Cu 2+ by FA and then formed coordination polymer-copper(II), which uniformly dispersed in reaction solution of 1, 4-dioxane. Subsequently the Cu 2+ was in-situ reduced and Cu-Pd alloys formed simultaneously. The in-situ prepared nano Cu-Pd/C catalyst exhibited the best performance with a complete FF conversion and FFA selectivity of 98.1%. Reaction conditions test suggested that the FFA selectivity was greatly dependent on the Cu content. The underlying mechanism revealed that the Pd in Cu-Pd alloys mainly promoted the FF conversion by enhancing hydrogen adsorption, while the nano Cu for increasing FFA selectivity; the Cu-Pd alloys functioned in synergistic way. Leaching and recycling tests demonstrated an excellent stability of the Cu-Pd/C catalyst.
Strengthened conductive shielded graphene/nano-Cu/crosslinking polyurethane (CPU) foam with ultrahigh interfacial functions was newly fabricated, involving the use of nano-assembly-freeze extraction route. The 3D supported modified graphene-nano-Cu (GC) interface were analyzed and verified efficiently by FTIR, XRD, XPS spectra and SEM, TEM images. Towards the CPU foams doped with GC network, surface polarity was weakened efficiently, and the anti-permeation efficiency was significantly improved due to the special positive piling behaviors of nanosheets. The initial decomposition temperature (enhanced by ∼22.2%) was efficiently delayed on account of heat transfer and doping protection. Thermal conductivity consistently fitted with modified Maxwell-Garnett method (D ∼ 5, K p /Km ∼ 1000) was increased by ∼338% due to the collaborative formation of phonon-electron transmission network. More importantly, the electric conductivity was increased by orders of magnitude, along with the verification of 3D synergistic transmission network using percolation threshold. As compared to the pure CPU material, a maximum electromagnetic interference shielding (EMI) effectiveness of over 55 dB in the frequency range of 0–9 GHz was demonstrated on the interface with only ∼0.87 vol% GC doping. All these suggest that the CPU foams simply doped with characteristic GC possesses a great potential to be used as lightweight, highly conductive, anti-penetrative and stable anti-interference materials.
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