- Photoactivation of Cu Centers in Metal-Organic Frameworks for Selective CO2 Conversion to Ethanol
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CO2 hydrogenation to ethanol is of practical importance but poses a significant challenge due to the need of forming one C-C bond while keeping one C-O bond intact. CuI centers could selectively catalyze CO2-to-ethanol conversion, but the CuI catalytic sites were unstable under reaction conditions. Here we report the use of low-intensity light to generate CuI species in the cavities of a metal-organic framework (MOF) for catalytic CO2 hydrogenation to ethanol. X-ray photoelectron and transient absorption spectroscopies indicate the generation of CuI species via single-electron transfer from photoexcited [Ru(bpy)3]2+-based ligands on the MOF to CuII centers in the cavities and from Cu0 centers to the photoexcited [Ru(bpy)3]2+-based ligands. Upon light activation, this Cu-Ru-MOF hybrid selectively hydrogenates CO2 to EtOH with an activity of 9650 μmol gCu-1 h-1 under 2 MPa of H2/CO2 = 3:1 at 150 °C. Low-intensity light thus generates and stabilizes CuI species for sustained EtOH production.
- Zeng, Lingzhen,Wang, Zhiye,Wang, Yongke,Wang, Jing,Guo, Ying,Hu, Huihui,He, Xuefeng,Wang, Cheng,Lin, Wenbin
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supporting information
p. 75 - 79
(2019/12/30)
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- In-Situ Nanostructuring and Stabilization of Polycrystalline Copper by an Organic Salt Additive Promotes Electrocatalytic CO2 Reduction to Ethylene
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Bridging homogeneous molecular systems with heterogeneous catalysts is a promising approach for the development of new electrodes, combining the advantages of both approaches. In the context of CO2 electroreduction, molecular enhancement of planar copper electrodes has enabled promising advancement towards high Faradaic efficiencies for multicarbon products. Besides, nanostructured copper electrodes have also demonstrated enhanced performance at comparatively low overpotentials. Herein, we report a novel and convenient method for nanostructuring copper electrodes using N,N′-ethylene-phenanthrolinium dibromide as molecular additive. Selectivities up to 70 % for C≥2 products are observed for more than 40 h without significant change in the surface morphology. Mechanistic studies reveal several roles for the organic additive, including: the formation of cube-like nanostructures by corrosion of the copper surface, the stabilization of these nanostructures during electrocatalysis by formation of a protective organic layer, and the promotion of C≥2 products.
- Thevenon, Arnaud,Rosas-Hernández, Alonso,Peters, Jonas C.,Agapie, Theodor
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supporting information
p. 16952 - 16958
(2019/11/21)
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- Artificial Photosynthesis of Methanol by Mn:CdS and CdSeTe Quantum Dot Cosensitized Titania Photocathode in Imine-Based Ionic Liquid Aqueous Solution
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The artificial photosynthesis (APS) of carbon-based chemicals from CO2 and water is a promising strategy for solar energy conversion and storage. A new Mn-doped CdS and CdSeTe quantum dot cosensitized TiO2 photocathode was fabricated and applied to CO2 reduction in an APS cell with modified BiVO4 as the counter electrode. The 3 D structure of the photocathode constructed by Mn:CdS and CdSeTe quantum dots showed a high efficiency for light harvesting and electron transfer in this system to yield methanol at a rate of 90 μm h?1 cm?2 at ?0.9 V versus the saturated calomel electrode under 200 mW cm?2 irradiation. Methanol could also be produced by a two-electrode system under the same conditions. 13CO2-labeling experiments were performed to show that the carbon-based products are derived from CO2. A mechanism for CO2 reduction in this new APS cell was proposed based on the experimental results. In addition, headspace GC was used to quantify the products by an external standard method.
- Nie, Rong,Ma, Wenjie,Dong, Yapeng,Xu, Yanjie,Wang, Jinyuan,Wang, Jianguo,Jing, Huanwang
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p. 3342 - 3350
(2018/08/24)
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- Metal-Free Nitrogen-Doped Mesoporous Carbon for Electroreduction of CO2 to Ethanol
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CO2 electroreduction is a promising technique for satisfying both renewable energy storage and a negative carbon cycle. However, it remains a challenge to convert CO2 into C2 products with high efficiency and selectivity. Herein, we report a nitrogen-doped ordered cylindrical mesoporous carbon as a robust metal-free catalyst for CO2 electroreduction, enabling the efficient production of ethanol with nearly 100 % selectivity and high faradaic efficiency of 77 % at ?0.56 V versus the reversible hydrogen electrode. Experiments and density functional theory calculations demonstrate that the synergetic effect of the nitrogen heteroatoms and the cylindrical channel configurations facilitate the dimerization of key CO* intermediates and the subsequent proton–electron transfers, resulting in superior electrocatalytic performance for synthesizing ethanol from CO2.
- Song, Yanfang,Chen, Wei,Zhao, Chengcheng,Li, Shenggang,Wei, Wei,Sun, Yuhan
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supporting information
p. 10840 - 10844
(2017/08/30)
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