- Efficient synthesis of ethanol by methanol homologation using CO2 at lower temperature
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CO2 transformation is an important topic in green chemistry, and methanol homologation using CO2 is a promising route to produce ethanol. In this work, we studied this reaction using different homogeneous catalytic systems. It was found that a [RuCl2(CO)3]2/Co4(CO)12 bimetallic catalyst using LiI as a promoter and N-ethyl-2-pyrrolidone (NEP) as the solvent was very effective under mild conditions. The reaction could proceed efficiently at 160 °C, which is much lower than that reported before. The turnover frequency (TOF) of ethanol based on Ru was as high as 7.5 h-1 and the selectivity of ethanol in total products could reach 65.0 C-mol%, which are obviously higher than those reported in the literature. Ethanol was synthesized through cascade catalysis of a reverse water gas shift (RWGS) reaction and methanol homologation with syngas (CO/H2). The outstanding performance of the catalytic system originated from the excellent cooperation of the components. The catalyst could be reused at least five times without any obvious decrease of the catalytic performance. The effect of the solvent on this reaction was studied systematically. The mechanism was also discussed based on isotope labeling tests.
- Wang, Ying,Zhang, Jingjing,Qian, Qingli,Asare Bediako, Bernard Baffour,Cui, Meng,Yang, Guanying,Yan, Jiang,Han, Buxing
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- Selective electrochemical reduction of carbon dioxide to ethanolviaa relay catalytic platform
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Efficient electroreduction of carbon dioxide (CO2) to ethanol is of great importance, but remains a challenge because it involves the transfer of multiple proton-electron pairs and carbon-carbon coupling. Herein, we report a CoO-anchored N-doped carbon material composed of mesoporous carbon (MC) and carbon nanotubes (CNT) as a catalyst for CO2electroreduction. The faradaic efficiencies of ethanol and current density reached 60.1% and 5.1 mA cm?2, respectively. Moreover, the selectivity for ethanol products was extremely high among the products produced from CO2. A proposed mechanism is discussed in which the MC-CNT/Co catalyst provides a relay catalytic platform, where CoO catalyzes the formation of CO* intermediates which spill over to MC-CNT for carbon-carbon coupling to form ethanol. The high selectivity for ethanol is attributed mainly to the highly selective carbon-carbon coupling active sites on MC-CNT.
- Chen, Bingfeng,Du, Juan,Han, Buxing,Li, Shaopeng,Liu, Huizhen,Liu, Shulin,Xin, Yu
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p. 5098 - 5104
(2020/06/09)
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- Hierarchical TiO2/Ni(OH)2 composite fibers with enhanced photocatalytic CO2 reduction performance
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In the past few years, Ni(OH)2 has been found to be an effective cocatalyst for photocatalytic hydrogen evolution. Herein, we report that it can also be used to enhance the photoreduction of CO2 into chemical fuels. Vertically aligned Ni(OH)2 nanosheets are deposited onto electrospinning TiO2 nanofibers via simple wet-chemical precipitation to manufacture TiO2/Ni(OH)2 hybrid photocatalysts. The TiO2 nanofibers can direct the ordered growth of Ni(OH)2 nanosheets, which have a thickness of 20 nm and uniformly cover the surface of the TiO2 substrate. The TiO2/Ni(OH)2 hierarchical composite displays remarkably improved photocatalytic CO2 reduction activity compared to that displayed by pristine TiO2 fibers. The bare TiO2 can only produce methane and carbon monoxide (1.13 and 0.76 μmol h-1 g-1, respectively) upon CO2 photoreduction. After loading 0.5 wt% Ni(OH)2, the methane yield increases to 2.20 μmol h-1 g-1, meanwhile the CO yield is unchanged. Interestingly, alcohols (methanol and ethanol) also appear as products, in addition to CH4 and CO, over the TiO2/Ni(OH)2 hybrid, and the maximum yield is reached with 15 wt% Ni(OH)2 loading (0.58 and 0.37 μmol h-1 g-1 for methanol and ethanol, respectively). This can be ascribed to an enhanced charge separation efficiency and higher CO2 capture capacity due to the presence of Ni(OH)2. These results demonstrate that Ni(OH)2 can not only improve the total CO2 conversion efficiency, but can also alter the product selectivity upon photocatalysis. This work opens a new pathway for achieving high-efficiency photocatalytic CO2 reduction with Ni(OH)2 as a cocatalyst.
- Meng, Aiyun,Wu, Shuang,Cheng, Bei,Yu, Jiaguo,Xu, Jingsan
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supporting information
p. 4729 - 4736
(2018/03/21)
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- Alternative pathways in the ruthenium catalysed hydrogenation of CO to alcohols
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CO hydrogenation in [PBu4]Br in the presence of [Ru 3(CO)12] gives predominantly methanol, ethanol and propanol with small amounts of 1,2-ethanediol. Using RuO2 as the catalyst precursor, the same products are f
- Blank, Jan H.,Hembre, Robert,Ponasik, James,Cole-Hamilton, David J.
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p. 218 - 223
(2014/01/06)
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- Molecular Structure of s-cis- and s-trans-Acrolein Determined by Microwave Spectroscopy
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The rotational spectra of highly enriched single D-, 13C-, and 18O-substituted species of acrolein have been measured and analyzed over 12-58 GHz.The complete substitution structure has been determined for the less abundant s-cis conformer from the ground-state rotational constants.In addition newly assigned μb-type transitions for all isotopic species of the more abundant s-trans-acrolein have improved the structure of this conformer.Careful measurements of the Stark effect have resulted in an accurate determination of the electric dipole moment of the s-trans conformer.A comparison of the molecular structures of the two conformers has revealed significant differences in the central C-C bonds.
- Blom, C. E.,Grassi, G.,Bauder, A
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p. 7427 - 7431
(2007/10/02)
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