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"Zhang, Gong"
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Tunable CO2 electroreduction to ethanol and ethylene with controllable interfacial wettability
The mechanism of how interfacial wettability impacts the CO
2
electroreduction pathways to ethylene and ethanol remains unclear. This paper describes the design and realization of controllable equilibrium of kinetic-controlled *CO and *H via modifying alkanethiols with different alkyl chain lengths to reveal its contribution to ethylene and ethanol pathways. Characterization and simulation reveal that the mass transport of CO
2
and H
2
O is related with interfacial wettability, which may result in the variation of kinetic-controlled *CO and *H ratio, which affects ethylene and ethanol pathways. Through modulating the hydrophilic interface to superhydrophobic interface, the reaction limitation shifts from insufficient supply of kinetic-controlled *CO to that of *H. The ethanol to ethylene ratio can be continuously tailored in a wide range from 0.9 to 1.92, with remarkable Faradaic efficiencies toward ethanol and multi-carbon (C
2+
) products up to 53.7% and 86.1%, respectively. A C
2+
Faradaic efficiency of 80.3% can be achieved with a high C
2+
partial current density of 321 mA cm
−2
, which is among the highest selectivity at such current densities.
The mechanism of how interfacial wettability impacts the CO
2
electcgq Herein, the authors describe the design and realization of controllable equilibrium of kinetic controlled *CO and *H to reveal its contribution to ethylene and ethanol pathways.
Journal Article
Supramolecular chiral polymeric aggregates: Construction and applications
Inspired by the mystery of natural homochirality, the design and construction of artificial chiral systems with special functions including mechanics, chiroptical devices, and chiral separation have aroused the great interest of scientists. Due to its diverse conformations and components, polymers become an excellent candidate to construct artificial chiral aggregates, which provides an opportunity to fabricate advanced chiral materials. Herein, in this review, we summarized not only the different strategies for construction and regulation of supramolecular chirality in chiral or achiral polymer systems, mainly including post‐assembly and polymerization‐induced chiral self‐assembly in chiral polymer systems and several chirality transfer and induction strategies in achiral polymer systems, but also the formation mechanisms of chiral aggregates by the chirality amplification from the molecular level to supramolecular level. Furthermore, we present the typical applications of chiral polymeric aggregates in circularly polarized light emission, chiral recognition and separation, and chiral elastomer. Finally, the current challenges and future directions of chiral polymeric aggregates are also elaborated. Recently polymers become excellent candidates to construct artificial chiral aggregates, due to the diverse conformations and components. Although regulating the chiral morphology is challenging in polymer aggregates, it attracts lots of research interests because of its crucial role in applications. Herein, this review summarizes typical examples of construction methods of supramolecular chirality in aggregated state and their applications.
Journal Article
Organocatalytic cycloaddition of alkynylindoles with azonaphthalenes for atroposelective construction of indole-based biaryls
The axially chiral indole-aryl motifs are present in natural products and biologically active compounds as well as in chiral ligands. Atroposelective indole formation is an efficient method to construct indole-based biaryls. We report herein the result of a chiral phosphoric acid catalyzed asymmetric cycloaddition of 3-alkynylindoles with azonaphthalenes. A class of indole-based biaryls were prepared efficiently with excellent yields and enantioselectivities (up to 98% yield, 99% ee). Control experiment and DFT calculations illustrate a possible mechanism in which the reaction proceeds via a dearomatization of indole to generate an allene-iminium intermediate, followed by an intramolecular aza-Michael addition. This approach provides a convergent synthetic strategy for enantioselective construction of axially chiral heterobiaryl backbones.
There is great interest in methods for catalytic enantioselective construction of axially chiral compounds found in natural products. Here, the authors develop a cycloaddition strategy for atroposelective construction of indole-based biaryls via chiral phosphoric acid-catalysed cycloaddition.
Journal Article
Efficient CO2 electroreduction on facet-selective copper films with high conversion rate
Tuning the facet exposure of Cu could promote the multi-carbon (C2+) products formation in electrocatalytic CO
2
reduction. Here we report the design and realization of a dynamic deposition-etch-bombardment method for Cu(100) facets control without using capping agents and polymer binders. The synthesized Cu(100)-rich films lead to a high Faradaic efficiency of 86.5% and a full-cell electricity conversion efficiency of 36.5% towards C2+ products in a flow cell. By further scaling up the electrode into a 25 cm
2
membrane electrode assembly system, the overall current can ramp up to 12 A while achieving a single-pass yield of 13.2% for C2+ products. An insight into the influence of Cu facets exposure on intermediates is provided by in situ spectroscopic methods supported by theoretical calculations. The collected information will enable the precise design of CO
2
reduction reactions to obtain desired products, a step towards future industrial CO
2
refineries.
Regulation of Cu facets to promote electrocatalytic CO
2
reduction is interesting and challenging. Here the authors describe a deposition-etch-bombardment synthetic approach to prepare Cu(100)-rich thin film electrodes for CO
2
electroreduction with over 50% ethylene Faradaic efficiency at a total current of 12 A.
Journal Article
The nature of active sites for carbon dioxide electroreduction over oxide-derived copper catalysts
The active sites for CO
2
electroreduction (CO
2
R) to multi-carbon (C
2+
) products over oxide-derived copper (OD-Cu) catalysts are under long-term intense debate. This paper describes the atomic structure motifs for product-specific active sites on OD-Cu catalysts in CO
2
R. Herein, we describe realistic OD-Cu surface models by simulating the oxide-derived process via the molecular dynamic simulation with neural network (NN) potential. After the analysis of over 150 surface sites through NN potential based high-throughput testing, coupled with density functional theory calculations, three square-like sites for C–C coupling are identified. Among them, Σ3 grain boundary like planar-square sites and convex-square sites are responsible for ethylene production while step-square sites, i.e.
n
(111) × (100), favor alcohols generation, due to the geometric effect for stabilizing acetaldehyde intermediates and destabilizing Cu–O interactions, which are quantitatively demonstrated by combined theoretical and experimental results. This finding provides fundamental insights into the origin of activity and selectivity over Cu-based catalysts and illustrates the value of our research framework in identifying active sites for complex heterogeneous catalysts.
The active sites over oxide-derived copper (OD-Cu) catalysts for CO
2
electroreduction are unclear. Here, the authors show atom-level product-specific active sites on OD-Cu surface models, where planar and convex square sites are responsible for ethylene while the step square site favours alcohols generation.
Journal Article