Electrochemical reduction of CO2 to CH3OH is of great interest. Aerogels have fine inorganic superstructure with high porosity and are known to be exceptional materials. Now a Pd−Cu bimetallic ...aerogel electrocatalyst has been developed for conversion of CO2 into CH3OH. The current density and Faradaic efficiency of CH3OH can be as high as 31.8 mA cm−2 and 80.0 % over the Pd83Cu17 aerogel at a very low overpotential (0.24 V). The superior performance of the electrocatalyst results from efficient adsorption and stabilization of the CO2 radical anion, high Pd0/PdII and CuI+Cu0/CuII ratios, and sufficient Pd/Cu grain boundaries of aerogel nanochains.
A Pd−Cu bimetallic aerogel was an outstanding electrocatalyst for conversion of CO2 into CH3OH in an aqueous solution of ionic liquid. The current density could reach 31.8 mA cm−2 with a Faradaic efficiency of 80.0 % over the Pd83Cu17 aerogel electrode at a low overpotential of 0.24 V.
The electrochemical synthesis of chemicals from carbon dioxide, which is an easily available and renewable carbon resource, is of great importance. However, to achieve high product selectivity for ...desirable C2 products like ethylene is a big challenge. Here we design Cu nanosheets with nanoscaled defects (2–14 nm) for the electrochemical production of ethylene from carbon dioxide. A high ethylene Faradaic efficiency of 83.2% is achieved. It is proved that the nanoscaled defects can enrich the reaction intermediates and hydroxyl ions on the electrocatalyst, thus promoting C–C coupling for ethylene formation.
Developing highly efficient electrocatalysts based on cheap and earth-abundant metals for CO
reduction is of great importance. Here we demonstrate that the electrocatalytic activity of ...manganese-based heterogeneous catalyst can be significantly improved through halogen and nitrogen dual-coordination to modulate the electronic structure of manganese atom. Such an electrocatalyst for CO
reduction exhibits a maximum CO faradaic efficiency of 97% and high current density of ~10 mA cm
at a low overpotential of 0.49 V. Moreover, the turnover frequency can reach 38347 h
at overpotential of 0.49 V, which is the highest among the reported heterogeneous electrocatalysts for CO
reduction. In situ X-ray absorption experiment and density-functional theory calculation reveal the modified electronic structure of the active manganese site, on which the free energy barrier for intermediate formation is greatly reduced, thus resulting in a great improvement of CO
reduction performance.
Highly efficient electrochemical reduction of CO2 to CH4 is of great importance, but is challenging. Herein, Zn-1,3,5-benzenetricarboxylic acid metal-organic frameworks (Zn-BTC MOFs) deposited on ...carbon paper (CP) were used as cathodes in electrochemical reduction of CO2 using ionic liquids (ILs) as the electrolytes, which was the first work on combination of a MOF electrode and an pure IL electrolyte in the electrochemical reduction of CO2. It was found that the efficiency of the reaction depended strongly on the morphology of the Zn-MOFs. Compared with the commonly used metal electrodes, the electrochemical reaction showed much higher selectivity to CH4 and current density, and the overpotentials for CH4 is much lower. The excellent combination of the MOF cathodes and ILs opens a way for reduction of CO2 to CH4 effectively.
Surfactant assemblies have a wide range of applications in areas such as the chemical industry, material science, biology, and enhanced oil recovery. From both theoretical and practical perspectives, ...researchers have focused on tuning the aggregation behaviors of surfactants. Researchers commonly use solid and liquid compounds such as cosurfactants, acids, salts, and alcohols as stimuli for tuning the aggregation behaviors. However, these additives can present economic and environmental costs and can contaminate or modify the product. Therefore researchers would like to develop effective methods for tuning surfactant aggregation with easily removable, economical, and environmentally benign stimuli. Supercritical or compressed CO2 is abundant, nontoxic, and nonflammable and can be recycled easily after use. Compressed CO2 is quite soluble in many liquids, and the solubility depends on pressure and temperature. Therefore researchers can continuously influence the properties of liquid solvents by controlling the pressure or temperature of CO2. In this Account, we briefly review our recent studies on tuning the aggregation behaviors of surfactants in different media using supercritical or compressed CO2. Supercritical or compressed CO2 serves as a versatile regulator of a variety of properties of surfactant assemblies. Using CO2, we can switch the micellization of surfactants in water, adjust the properties of reverse micelles, enhance the stability of vesicles, and modify the switching transition between different surfactant assemblies. We can also tune the properties of emulsions, induce the formation of nanoemulsions, and construct novel microemulsions. With these CO2-responsive surfactant assemblies, we have synthesized functional materials, optimized chemical reaction conditions, and enhanced extraction and separation efficiencies. Compared with the conventional solid or liquid additives, CO2 shows some obvious advantages as an agent for modifying surfactant aggregation. We can adjust the aggregation behaviors continuously by pressure and can easily remove CO2 without contaminating the product, and the method is environmentally benign. We can explain the mechanisms for these effects on surfactant aggregation in terms of molecular interactions. These studies expand the areas of colloid and interface science, supercritical fluid science and technology, and chemical thermodynamics. We hope that the work will influence other fundamental and applied research in these areas.
Metal–organic frameworks (MOFs) have proven to be an interesting class of sacrificial precursors of functional inorganic materials for catalysis, energy storage, and conversion applications. However, ...the controlled synthesis of MOF-derived materials with desirable compositions, structures, and properties still remains a big challenge. Herein, we propose a post-solvothermal route for the outer-to-inner loss of organic linkers from MOF, which is simple, rapid, and controllable and can be operated at temperature much lower than that of the commonly adopted pyrolysis method. By such a strategy, the MIL-125-NH2 particles coated by TiO2 nanosheets were produced, and the thickness of TiO2 shell can be easily tuned. The MIL-125-NH2@TiO2 core–shell particles combine the advantages of highly active TiO2 nanosheets, MIL-125-NH2 photosensitizer, plenty of linker defects and oxygen vacancies, and mesoporous structure, which allows them to be utilized as photocatalysts for the visible-light-driven hydrogen production reaction. It is remarkable that the hydrogen evolution rate by MIL-125-NH2@TiO2 can be enhanced 70 times compared with the pristine MIL-125-NH2. Such a route can be easily applied to the synthesis of different kinds of MOF-derived functional materials.
To develop photocatalysts with desirable compositions and structures for improving the efficiency and selectivity of CO2 conversion to CH4 under mild conditions is of great importance. Here, we ...design an effective photocatalyst of bimetal (Ag/Pd) nanoalloys supported on nitrogen-doped TiO2 nanosheet for CO2 conversion. Such a novel photocatalyst combines multiple advantages of abundant Ti3+ ions, oxygen vacancies, and substitutional nitrogen that are favorable for catalyzing CO2 reduction. It was found that CO2 could be efficiently transformed to CH4 under mild conditions, i.e., in aqueous solution and at atmospheric pressure and room temperature. The maximum production rate of CH4 can reach 79.0 μmol g–1 h–1. Moreover, the Ag/Pd bimetals supported on N-doped TiO2 nanosheet exhibit high selectivity to CH4. The as-synthesized photocatalyst can be well recycled for CO2 reduction.
Abstract
Methanol is a highly desirable product of CO
2
electroreduction due to its wide array of industrial applications. However, the development of CO
2
-to-methanol electrocatalysts with high ...performance is still challenging. Here we report an operationally simple in situ dual doping strategy to construct efficient CO
2
-to-methanol electrocatalysts. In particular, when using Ag,S-Cu
2
O/Cu as electrocatalyst, the methanol Faradaic efficiency (FE) could reach 67.4% with a current density as high as 122.7 mA cm
−2
in an H-type cell using 1-butyl-3-methylimidazolium tetrafluoroborate/H
2
O as the electrolyte, while the current density was below 50 mA cm
−2
when the FE was greater than 50% over the reported catalysts. Experimental and theoretical studies suggest that the anion S can effectively adjust the electronic structure and morphology of the catalysts in favor of the methanol pathway, whereas the cation Ag suppresses the hydrogen evolution reaction. Their synergistic interactions with host material enhance the selectivity and current density for methanol formation. This work opens a way for designing efficient catalysts for CO
2
electroreduction to methanol.
Electrochemical conversion of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. The Cu‐based catalysts feature unique superiorities, but achieving high ethylene selectivity is ...still restricted. In this study, we propose the anchoring of an ionic liquid (IL) on a Cu electrocatalyst for improving the electrochemical CO2 reduction to ethylene. In a water‐based electrolyte and a commonly used H‐type cell, a high ethylene Faradaic efficiency of 77.3 % was achieved at −1.49 V (vs. RHE). Experimental and theoretical studies reveal that an IL can modify the electronic structure of a Cu catalyst through its interaction with Cu, making it more conducive to *CO dimerization for ethylene formation.
The ionic liquid 1‐butyl‐3‐methylimidazolium nitrate (BmimNO3) was anchored into Cu, through which the atomic coordination and electronic properties of Cu can be optimized to facilitate C−C coupling. This electrocatalyst can reduce CO2 to C2H4 with high selectivity. The Faradaic efficiency of C2H4 reaches 77.3 % at −1.49 V (vs. RHE) in KHCO3 aqueous solution using a H‐type cell, much higher than that over pure Cu catalyst (31.2 %).
MADS-box family genes encode transcription factors that are involved in multiple developmental processes in plants, especially in floral organ specification, fruit development, and ripening. However, ...a comprehensive analysis of tomato MADS-box family genes, which is an important model plant to study flower fruit development and ripening, remains obscure. To gain insight into the MADS-box genes in tomato, 131 tomato MADS-box genes were identified. These genes could be divided into five groups (Mα, Mβ, Mγ, Mδ, and MIKC) and were found to be located on all 12 chromosomes. We further analyzed the phylogenetic relationships among Arabidopsis and tomato, as well as the protein motif structure and exon-intron organization, to better understand the tomato MADS-box gene family. Additionally, owing to the role of MADS-box genes in floral organ identification and fruit development, the constitutive expression patterns of MADS-box genes at different stages in tomato development were identified. We analyzed 15 tomato MADS-box genes involved in floral organ identification and five tomato MADS-box genes related to fruit development by qRT-PCR. Collectively, our study provides a comprehensive and systematic analysis of the tomato MADS-box genes and would be valuable for the further functional characterization of some important members of the MADS-box gene family.
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