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229 results on '"Kong, Lichun"'

3. Selective Increase in CO2 Electroreduction to Ethanol Activity at Nanograin‐Boundary‐Rich Mixed Cu(I)/Cu(0) Sites via Enriching Co‐Adsorbed CO and Hydroxyl Species.

Author

Zhang, Ting, Xu, Shenglin, Chen, De‐Li, Luo, Ting, Zhou, Jinlei, Kong, Lichun, Feng, JiuJu, Lu, Ji‐Qing, Weng, Xuexiang, Wang, Ai‐Jun, Li, Zhengquan, Su, Yaqiong, and Yang, Fa

Subjects
ELECTROCHEMICAL analysis, COPPER surfaces, STANDARD hydrogen electrode, COPPER, RADIOLABELING
Abstract

Selective producing ethanol from CO2 electroreduction is highly demanded, yet the competing ethylene generation route is commonly more thermodynamically preferred. Herein, we reported an efficient CO2‐to‐ethanol conversion (53.5 % faradaic efficiency at −0.75 V versus reversible hydrogen electrode (vs. RHE)) over an oxide‐derived nanocubic catalyst featured with abundant "embossment‐like" structured grain‐boundaries. The catalyst also attains a 23.2 % energy efficiency to ethanol within a flow cell reactor. In situ spectroscopy and electrochemical analysis identified that these dualphase Cu(I) and Cu(0) sites stabilized by grain‐boundaries are very robust over the operating potential window, which maintains a high concentration of co‐adsorbed *CO and hydroxyl (*OH) species. Theoretical calculations revealed that the presence of *OHad not only promote the easier dimerization of *CO to form *OCCO (ΔG~0.20 eV) at low overpotentials but also preferentially favor the key *CHCOH intermediate hydrogenation to *CHCHOH (ethanol pathway) while suppressing its dehydration to *CCH (ethylene pathway), which is believed to determine the remarkable ethanol selectivity. Such imperative intermediates associated with the bifurcation pathway were directly distinguished by isotope labelling in situ infrared spectroscopy. Our work promotes the understanding of bifurcating mechanism of CO2ER‐to‐hydrocarbons more deeply, providing a feasible strategy for the design of efficient ethanol‐targeted catalysts. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Efficient and Selective Electroreduction of CO2 to HCOOH over Bismuth‐Based Bromide Perovskites in Acidic Electrolytes.

Author

Wang, Yan, Wang, Chun, Wei, Yi, Wei, Fang, Kong, Lichun, Feng, Jiuju, Lu, Ji‐Qing, Zhou, Xiaocheng, and Yang, Fa

Subjects
ELECTROLYTIC reduction, ELECTROLYTES, PEROVSKITE, ACTIVATION energy, METAL halides, OPTOELECTRONIC devices, CHEMICAL weathering, HYDROGEN evolution reactions
Abstract

Metal halide perovskites, primarily used as optoelectronic devices, have not been applied for electrochemical conversion due to their insufficient stability in moisture. Herein, two bismuth‐based perovskites are introduced as novel electrocatalysts to convert CO2 into HCOOH in aqueous acidic media (pH 2.5), exhibiting a high Faradaic efficiency for HCOOH of >80 % in a wide potential range from −0.75 to −1.25 V. Their structural evolution against water was dynamically monitored by in situ spectra. Theoretical calculations further reveal that the formation of intermediate OCHO* on bismuth sites of Cs3Bi2Br9(111) play a pivotal role toward HCOOH production, which has a lower energy barrier than that on Cs2AgBiBr6(001) surfaces. Significantly, CO2 reacts with protons instead of water which can enhance CO2 reduction rate and suppress hydrogen evolution by avoiding carbonate formation in acidic electrolytes. This work paves the way for the extensive investigation of halide perovskites in aqueous systems. [ABSTRACT FROM AUTHOR]

Published
2022
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31. Z‐Selective α‐Arylation of α,β‐Unsaturated Nitriles via [3,3]‐Sigmatropic Rearrangement.

Author

Chen, Mengyuan, Liang, Yuchen, Dong, Taotao, Liang, Weijian, Liu, Yanping, Zhang, Yage, Huang, Xin, Kong, Lichun, Wang, Zhi‐Xiang, and Peng, Bo

Subjects
NITRILES, LEWIS bases, ORGANIC synthesis, BAYLIS-Hillman reaction, ARYLATION
Abstract

The Morita‐Baylis–Hillman (MBH) reaction and [3, 3]‐sigmatropic rearrangement are two paradigms in organic synthesis. We have merged the two types of reactions to achieve [3,3]‐rearrangement of aryl sulfoxides with α,β‐unsaturated nitriles. The reaction was achieved by sequentially treating both coupling partners with electrophilic activator (Tf2O) and base, offering an effective approach to prepare synthetically versatile α‐aryl α,β‐unsaturated nitriles with Z‐selectivity through direct α‐C‐H arylation of unmodified α,β‐unsaturated nitriles. The control experiments and DFT calculations support a four‐stage reaction sequence, including the assembly of Tf2O activated aryl sulfoxide with α,β‐unsaturated nitrile, MBH‐like Lewis base addition, [3,3]‐rearrangement, and E1cB‐elimination. Among these stages, the Lewis base addition is diastereoselective and E1cB‐elimination is cis‐selective, which could account for the remarkable Z‐selectivity of the reaction. [ABSTRACT FROM AUTHOR]

Published
2021
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32. Ferric nitrate-catalyzed aerobic oxidative ring-opening of substituted furans for the stereoselective synthesis of (Z)-1,4-enediones

Author

Ye, Tao, Lin, Na, Shen, Jia-Huan, Kong, Lichun, Liu, Yang-Zi, Wang, Quannan, and Deng, Wei-Ping

Abstract

A simple and highly efficient catalytic system for the selective aerobic oxidative ring-opening of substituted furans has been achieved using Fe(NO3)3·9H2O as a catalyst and air as an oxidant under mild conditions. A series of (Z)-1,4-enediones were obtained in good yields (up to 97%) with excellent stereoselectivity (up to ​> ​20:1 Z/Eratio). The present synthetic method exhibits perfect atom economy, wide substrate scope, and highly functionalized products allowing diverse transformations.

Published
2024
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33. Nickel-Catalyzed Remote Arylation of Alkenyl Aldehydes Initiated by Radical Alkylation with Tertiary α-Carbonyl Alkyl Bromides

Author

Jin, Weiwei, Zhou, Yulu, Zhao, Ying, Ma, Qianqian, Kong, Lichun, and Zhu, Gangguo

Abstract

A novel nickel-catalyzed remote arylation of alkenyl aldehydes triggered by radical alkylation with tertiary α-carbonyl alkyl bromides is described, thus producing a quaternary carbon center containing ketones in promising yields with broad functional group compatibility. Preliminary mechanistic studies suggest that the combination of a 1,n-HAT (n= 5 or 6) from alkyl radicals to aldehyde C–H bonds with nickel catalysis may account for the realization of this reaction.

Published
2024
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38. Visible-light-driven photocatalytic CO2reduction over ketoenamine-based covalent organic frameworks: role of the host functional groupsElectronic supplementary information (ESI) available. See DOI: 10.1039/d0cy02061c

Author

Peng, Lianlian, Chang, Shuqing, Liu, Ziling, Fu, Yanghe, Ma, Rui, Lu, Xinqing, Zhang, Fumin, Zhu, Weidong, Kong, Lichun, and Fan, Maohong

Abstract

The photocatalytic conversion of CO2into valuable chemicals is a promising and sustainable approach for solving the worldwide environmental and energy problems. In the current work, a series of ketoenamine-based covalent organic frameworks (COFs) with different functional groups in the same host framework, named TpBD-X [X = –H2, –(CH3)2, –(OCH3)2, and –(NO2)2], were synthesized to study how different functional groups affect the overall photocatalytic CO2reduction for the first time. The differences in morphology, light-absorption intensity, and band gap among these functionalized COFs were also investigated. Compared to the electron-withdrawing groups, the electron-donating groups in TpBD can have a stronger conjugation effect and accelerate photogenerated charge separation and transfer, thereby improving the photocatalytic performance for CO2reduction. This work is beneficial for the understanding of the effects of the functional groups on the light-absorption intensity, band gap, and charge transfer that are key parameters in photocatalysis, and therefore provides a new approach for designing efficient COF-based photocatalysts for CO2reduction.

Published
2021
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40. Recent Advances on Oxidative Radical Addition to Aldehydes

Author

Zhu Gangguo, Fang Luo, Yulu Zhou, and Kong Lichun

Subjects
010405 organic chemistry, Chemistry, Organic Chemistry, Organic chemistry, Oxidative phosphorylation, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences
Published
2018

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