Journal of Physical Chemistry C
·
2019
·
IF 4.309
Tao Liu,Cong Xi,Cunku Dong,Chuanqi Cheng,Jiayi Qin,Shanwei Hu,Hui Liu,Xi-Wen Du
Interfacial electron transfer (IET) at the metal–solution interface is known as a rate-determining step for many electrocatalytic reactions. Hitherto, there is still lack of physical insight into the IET process, as well as an experimental physical quantity directly linked to the IET rate. In this work, we propose that the work function can serve as an indicator for the IET rate of same metals such as silver quantum mechanical analysis demonstrates that a decrease in the work function can dramatically enhance the IET process. To experimentally verify this hypothesis, three different silver catalysts are prepared for CO2 electroreduction. The experimental results confirm that reducing work function of silver catalysts can improve the IET, according to the change of the Tafel slope. Resultantly, the silver catalyst with smaller work function achieves higher activity and selectivity for CO production. This study demonstrates a promising strategy to enhance the performance of same metal catalysts through tuning its work function.
研究领域:
物理化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Haiqiang Lin,Hongyan Qu,Weikun Chen,Kang Xu,Jianwei Zheng,Xinping Duan,Hesheng Zhai,Youzhu Yuan
In gas-phase chemoselective hydrogenation of crotonaldehyde on Ag-based catalysts, zirconia doping on silica supports was found to improve catalytic performance in terms of unsaturated alcohol selectivity, hydrogenation activity, and stability. The surface modification of silica by zirconia doping favors the fine dispersion of Ag species due to the enhanced quantity and strength of surface acid sites, which enable construction of abundant catalytic sites effective for C O bond hydrogenation. High crotyl alcohol selectivity, exceeding 80%, and significant inhibition of monohydrogenation on the C C bond were observed on the optimal Ag/Zr–SiO 2 catalyst. Dynamic O 2 chemisorption measurement revealed that the pure Ag powders did not chemisorb O 2 irreversibly under 323 K, but SiO 2 or Zr–SiO 2 supported Ag catalysts did. The amounts of Ag active for O 2 chemisorption, which are at least one order of magnitude lower than that of surface Ag derived from TEM and XRD characterizations, match well with the perimeter interface Ag of hemispherical particles. A strong correlation between hydrogenation activity and O 2 uptake on those Ag/SiO 2 and Ag/Zr–SiO 2 catalysts with different Ag dispersions and deactivation degrees was observed, implying that the effective catalytic sites for crotonaldehyde chemoselective hydrogenation may originate from accessible interface sites with unique redox properties. Catalyst induction and deactivation were observed on both Ag/SiO 2 and Ag/Zr–SiO 2 catalysts in real catalytic operation. Changes in metal stable interface structure, rather than metal aggregation and coagulation, are assumed to be the main cause of irreversible catalyst deactivation, because the apparent Ag particle sizes changed slightly, but the oxygen chemisorption ability deteriorated considerably. Electropositive Ag sites interacting with neighboring oxygen from oxide supports at the ternary Ag–ZrO 2 –SiO 2 interface are proposed to account for highly selective C O bond hydrogenation to produce the desired unsaturated alcohol.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 59
·54020-54026
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IF 3.289
Jikuan Qiu,Yuling Zhao,Huiyong Wang,Guokai Cui,Jianji Wang
Development of new efficient catalytic systems for chemical transformation of CO2 is a very attractive topic in green chemistry. In this work, we studied the synthesis of α-alkylidene cyclic carbonates through the coupling reaction between propargylic alcohols and CO2 with new silver catalysts. It was found that activated carbon supported AgX (X = Br and I) was a simple and efficient catalyst for the carboxylative cyclization of propargyl alcohols with CO2 at atmospheric pressure and room temperature. Nearly 99% yield of the desired product was obtained, and the product could be simply separated through solvent extraction. Moreover, the catalyst could be easily recovered and reused at least ten times without a decrease in the catalytic activity and selectivity. These findings are useful for the development of an environmentally friendly chemical process for the production of α-alkylidene cyclic carbonates.
研究领域:
绿色化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Jinglin Zou,Xinping Duan,Xu Liu,Lele Huang,Xiaoying Liu,Jiachang Zuo,Weizhou Jiao,Haiqiang Lin,Linmin Ye,Youzhu Yuan
Deciphering intrinsic reactive sites of metal–oxide catalysts, where the outer surface and/or interfaces coupled with oxygen species in the vicinity of nanoparticles concurrently work, remains a challenge. Given the extreme complexity of heterogeneous catalysis ( e.g. , metal catalysts for preliminary hydrogenation process), catalytically active sites, the activity origin, and reaction mechanism generally present a so-called 'black box'. Herein, Ag/ZrO 2−x achieves a higher intrinsic hydrogenation rate for selective scission of C O bond per mass Ag than the reference Ag/SiO 2 catalyst, as illustrated by the preliminary hydrogenation of dimethyl oxalate to methyl glycolate. The in-depth characterization revealed that the Ag δ+ –O v –Zr 3+ (Ag δ+ –O–Zr 4+ , O v refers to as oxygen vacancy) structure could be engineered owing to the higher affinity of Ag for the partially reduced ZrO 2 surface and heteroatom junctions (in preference to the inert support, such as SiO 2 and Al 2 O 3 ). Furthermore, the local environment of different crystallite phases (tetragonal or monoclinic ZrO 2 ) induced tunable (electronic) metal–support interactions (EMSIs), resulting in enhanced catalytic activity and ultra-stability for C O bond hydrogenation. XPS, methyl acetate-TPD, and in situ DRIFTS results unveiled the activity origin of silver–oxide systems, where the location of active metal sites for distinct functionalities over superficial and interfacial phases was validated. The mediated O v was verified to stabilize the thermodynamically unstable metallic (Ag 0 ) and charged silver species (Ag + or Ag n δ+ ). More importantly, time-resolved DRIFTS confirmed the crucial interfacial sites of Ag–ZrO 2−x for regioselective C O bond adsorption and activation. Further, the distinct active sites over Ag–ZrO 2−x may release the altered reaction mechanisms, i.e. , conventional Langmuir–Hinshelwood (LH) on Ag/SiO 2 versus quasi Mars–Van Krevelen process (Ag–ZrO 2−x ), which presents the new pathway for regioselective C O bond hydrogenation. The coordinated EMSIs were proposed as the origin of the catalytic activity caused by the synergistic catalysis of the interfacial/superficial sites. These findings rationalize the underlying understanding of the EMSI and highlight the instructive role for perceiving the structure-performance relationships and the activity origin in heterogeneous catalysts, thus moving away from the 'black-box' cognition.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2025
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IF 2.5
Lin Ai,Hui Ding,Yutong Jiao,Zeling Zhou,Xiao-Feng Wu,Peidong Li,Shengjun Huang
In the field of heterogeneous catalysis, the selective hydrogenation of α,β-unsaturated aldehyde to α,β-unsaturated alcohol is a prominent focus in the synthesis of fine chemicals. Herein, we present a straightforward protocol for constructing hierarchical zeolite supported catalysts for the gas-phase selective hydrogenation of α-methylacrolein to methallyl alcohol. Compared to the original microporous zeolite, the incorporation of mesoporous channels within the hierarchical zeolite gives rise to ample space to embed Ag nanoparticles, thereby delivering a positive effect on enhancing accessibility to metal active sites and leading to increased reactivity. Moreover, unlike the typical transition metals (Pt, Ni, Cu and Co), the unique surface properties of metal Ag inherently plays a crucial role in the formation of a desirable adsorption configuration. The resulting vertical orientation (on-top η1-σ(O) mode) causes the carbonyl group to interact with the Ag active sites via the terminal oxygen atom, while the C=C bond tilts away from the metal surface. Specifically, the selectivity to the targeting methallyl alcohol reaches ~75% over the hierarchical ZSM-5 and Silicalite-1 supported Ag catalysts under optimal reaction conditions. This discovery highlights the significance of pore architecture and adsorption configuration on the catalytic performance, and aims to deepen understanding for the rational design of heterogeneous catalysts in the gas-phase selective hydrogenation of α,β-unsaturated aldehydes.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
LETTERS IN ORGANIC CHEMISTRY
·
2024
·Vol. 22
·期 1
·56-60
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IF 0.7
Xin-Yu Lin,Guo-Jun Chen,Su-Zhe Wu,Ke-Xuan Xu,Xiao-Tian Zhang,Qi Feng
4-Hydroxyquinoline-2(1H)-ones exhibit multiple biological activities, and studying their synthetic methods is of great significance. In the presence of tetramethylguanidine and silver nitrate, 4-hydroxyquinoline-2(1H)-ones were efficiently synthesized from 2-ethynylanilines and carbon dioxide under atmospheric pressure. The reaction conditions, such as types of silver catalysts and reaction solvents, were optimized, and the applicability of the substrate was preliminarily investigated. This method provides an alternative pathway for the synthesis of 4-hydroxyquinoline-2(1H)-ones and the conversion and utilization of carbon dioxide.
研究领域:
有机化学
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药物化学
✓ 已验证
DOI
高影响因子
Green Energy & Environment
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2021
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IF 8.207
Kaihang Sun,Zhitao Zhang,Chenyang Shen,Ning Rui,Chang-jun Liu
Silver catalyst has been extensively investigated for photocatalytic and electrochemical CO 2 reduction. However, its high activity for selective hydrogenation of CO 2 to methanol has not been confirmed. Here, the feasibility of the indium oxide supported silver catalyst was investigated for CO 2 hydrogenation to methanol by the density functional theoretical (DFT) study and then by the experimental investigation. The DFT study shows there exists an intense Ag–In 2 O 3 interaction, which causes silver to be positively charged. The positively charged Ag species changes the electronic structure of the metal, facilitates the formation of the Ag–In 2 O 3 interfacial site for activation and dissociation of carbon dioxide. The promoted CO 2 dissociation leads to the enhanced methanol synthesis via the CO hydrogenation route as CO 2 ∗→CO∗→HCO∗→H 2 CO∗→H 3 CO∗→H 3 COH∗. The Ag/In 2 O 3 catalyst was then prepared using the deposition-precipitation method. The experimental study confirms the theoretical prediction. The methanol selectivity of CO 2 hydrogenation on Ag/In 2 O 3 reaches 100.0% at reaction temperature of 200 °C. It remains more than 70.0% between 200 and 275 °C. At 300 °C and 5 MPa, the methanol selectivity still keeps 58.2% with a CO 2 conversion of 13.6% and a space-time yield (STY) of methanol of 0.453 g methanol g cat −1 h −1 , which is the highest methanol STY ever reported for silver catalyst. The catalyst characterization confirms the intense Ag–In 2 O 3 interaction as well, which causes high Ag dispersion, increases and stabilizes the oxygen vacancies and creates the active Ag–In 2 O 3 interfacial site for the enhanced CO 2 hydrogenation to methanol.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2017
·Vol. 36
·期 2
·147-152
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IF 1.852
Qing-Wen Song,Ping Liu,Li-Hua Han,Kan Zhang,Liang-Nian He
One-pot two-step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver-catalysed C-O/C-N bond formation is reported. Catalytic activities were investigated by controlling catalyst loading, reaction pressure and time, and very high turnover number (turnover frequency) was obtained: 3350 (35 h −1 ) with 0.01 mol% silver catalyst under 0.1 MPa, and up to 13360 (139 h −1 ) with 0.005 mol% silver catalyst under 2.0 MPa at room temperature. The strategy was ingeniously regulated, and synchronously afforded a wide range of β-oxopropylcarbamate and 1,3-oxazolidin-2-one motifs in excellent yields and selectivity together with unprecedented high turnover number (TON) and turnover frequency (TOF) value.
研究领域:
化学
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材料科学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
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2022
·Vol. 24
·期 16
·9188-9195
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IF 3.945
Xifeng Luo,Ran Jiang,Ziang Ma,Tiantian Yang,Hui Liu,Hui Deng,Wenhong Wu,Cunku Dong,Xi-Wen Du
The work function can serve as a characteristic quantity to evaluate the catalytic activity due to its relationship with the surface structure of a material. However, what factors determine the influence of the work function on the electrochemical performance are still unclear. Herein, we elucidate the effect of the work function of Ag on the electrochemical reduction of CO2 to CO by controlling the ratio of exposed crystalline planes. To this end, the exposed surface of Ag powder was regulated by high-energy ball milling and its influence on CO2 reduction was investigated. The surface structure with more Ag(110) surface achieves higher activity and selectivity for CO production, resulting from the lower work function of Ag(110), which dramatically enhances the electron tunnelling probability during CO2 electroreduction. We found that a higher ratio of Ag(110) to Ag(100) leads to a lower work function and thus better electrochemical activity and selectivity. This study demonstrates a promising strategy to enhance the electrochemical performance of metal catalysts through tuning their work functions via regulating exposed crystalline planes.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Zuwei Luo,Yun Shen,Di Fang,Chuanchao He,Yueqiang Cao,Wei Li,Yi-An Zhu,Jinghong Zhou,Xinggui Zhou
Support materials play vital roles in heterogenous catalysis via the so-called support effects, and understanding on the support effects is beneficial for the design of high-performance catalysts. Herein, we represent detailed investigations on the support effects of Ag catalysts for dimethyl glycolate (DMO) semi-hydrogenation to methyl glycolate (MG), where G6 silica with amorphous mesopores, SBA-15 with parallel mesopores and silica nanospheres (MSNS) with center-radial ones were employed as the supports. The hydrogenation activity decreases in the order of Ag/MSNS > Ag/SBA-15 > Ag/G6 while the MG selectivity in the order of Ag/G6 > Ag/MSNS > Ag/SBA-15 at the same reaction conditions, indicating remarkable support effects on both activity and selectivity. Structural characterizations, temperature programmed experiments and in-situ FTIR of DMO adsorption experiments demonstrate that the weak confinement effect of G6 leads to the larger sized Ag nanoparticles and weakened activation of DMO and H 2 , which contributes to low hydrogenation activity. In contrast, the ordered mesoporous SBA-15 and MSNS deliver well confinement effects for Ag nanoparticles and the activation of DMO and H 2 , but the distinct pore structures result in different activation and diffusion behaviors. Finally, DMO conversion and MG yield are well correlated with the competitive adsorption of H 2 versus DMO on Ag catalysts, indicating such competitivity as a descriptor for DMO semi-hydrogenation over Ag catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemElectroChem
·
2020
·Vol. 7
·期 8
·1869-1876
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IF 4.154
Jinlong Sun,Jie Xu,Hui Jiang,Xinsheng Zhang,Dongfang Niu
Graphical Multiple roles : Three carbon nanotubes (CNTs)-supported Ag catalysts with precise tuning oxygen functional groups were reasonably designed/synthesized and applied into efficient electrochemical conversion of CO 2 to CO. The surface carboxyl groups on the CNTs play essential roles in loading Ag nanoparticles and tuning surface acidic environment of catalysts, and the rich surface protons are proved to be important for promoting the formation of intermediate, which could effectively improve the CO production. Carbon nanotubes (CNTs)-supported metal-based catalysts applied in the electrochemical reduction of CO 2 (CO 2 ER) have attracted extensive research recently. Nevertheless, insight into the roles of surface oxygen functional groups in these catalysts on CO 2 ER is still deficient. Herein, three catalysts were reasonably fabricated by chemically loading Ag nanoparticles (NPs) on the oxygenic CNTs (CNT−COOH, CNT−OH and CNT−CO) with precise tuning oxygen functional groups, and then used to explore the effect of oxygen functional groups on the electrocatalytic performance of Ag NPs for CO 2 ER. Compared with the other two counterparts, Ag/CNT−COOH with the highest content of carboxyl groups possesses the most uniform size and dispersion of Ag NPs and the strongest surface acidic environment, which enable it to exhibit the highest current density and Faradaic efficiency for CO production at high overpotential region ( E ≤−1.0 V vs. RHE). This work broadens the understanding of surface oxygen functional groups of catalysts in enhancing CO 2 ER performance, and provides guidance for the design and synthesis of high-performance catalysts.
研究领域:
材料科学
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催化化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
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IF 4.803
Zhiqiao He,Tao Liu,Juntao Tang,Chaoyi Zhou,Lingsha Wen,Jianmeng Chen,Shuang Song
To improve the activity, selectivity and stability of silver electrodes towards CO 2 electroreduction to CO, three-dimensional frameworks comprised of the metallic silver electrocatalyst particles were constructed on bulk silver surfaces using a successive double-potential pulses method. With the help of X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy, it was found that the as-synthesized silver particles exhibited a truncated hexagonal bipyramidal morphology, which was assembled from silver seeds with two {111} bases as well as laterally exposed {100} and {111} facets. Potential-dependent results revealed that the modified electrode exhibited an earlier onset potential, higher Faradaic efficiency and greater current density for CO evolution when compared to its smooth-surface counterpart. Moreover, as opposed to the bulk silver electrode losing its activity as a function of time, the activity of the improved electrode was durably stable over three successive 4 h periods. It is proposed that, in addition to the relatively vast electrochemical surface area, the exposed edges of the silver particles play a major role in enhancing the intrinsic activity and selectivity of the silver electrocatalyst by stabilizing the surface-adsorbed COOH species. Meanwhile, the existence of a large proportion of low-index {111} planes facilitates the desorption of the reduction intermediates of adsorbed CO species, suppressing the deactivation of the silver electrode towards CO 2 reduction.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）