APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Fang Li,Geun Ho Gu,Changhyeok Choi,Praveen Kolla,Song Hong,Tai-Sing Wu,Yun-Liang Soo,Justus Masa,Sanjeev Mukerjee,Yousung Jung,Jieshan Qiu,Zhenyu Sun
We report a unique 2D bismuth metal-organic framework (Bi-MOF) that possesses permanent accessible porosity for efficient electrochemical CO 2 reduction (ECR) to HCOOH. The 2D open-framework structure with helical Bi-O rods bridged by tritopic carboxylate ligands exhibits a remarkable Faradaic efficiency for HCOOH formation over a broad potential window, reaching 92.2 % at ∼ –0.9 V ( vs . reversible hydrogen electrode, RHE) with excellent durability over 30 h. The mass-specific HCOOH partial current density is up to 41.0 mA mg Bi −1 , exceeding 4 times higher than that of commercial Bi 2 O 3 and Bi sheets at ∼ –1.1 V ( vs . RHE). Operando and ex-situ X-ray absorption fine structure spectroscopy revealed a structural feature associated with Bi-MOF to preserve Bi(3+) during and after long-term ECR. Theoretical calculations further showed that the crystallographically channels with abundant Bi active sites in the MOF structure favor the formation of *HCOO while suppressing the side-reaction of hydrogen evolution, thereby leading to the high selectivity for HCOOH.
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高影响因子
Nature Catalysis
·
2020
·Vol. 3
·期 4
·411-417
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IF 30.471
Zhang Xiaoben,Han Shaobo,Zhu Beien,Zhang Guanghui,Li Xiaoyan,Gao Yi,Wu Zhaoxuan,Yang Bing,Liu Yuefeng,Baaziz Walid,Ersen Ovidiu,Gu Meng,Miller Jeffrey T.,Liu Wei
The high catalytic performance of core–shell nanoparticles is usually attributed to their distinct geometric and electronic structures. Here we reveal a dynamic mechanism that overturns this conventional understanding by a direct environmental transmission electron microscopy visualization coupled with multiple state-of-the-art in situ techniques, which include synchrotron X-ray absorption spectroscopy, infrared spectroscopy and theoretical simulations. A Ni–Au catalytic system, which exhibits a highly selective CO production in CO 2 hydrogenation, features an intact ultrathin Au shell over the Ni core before and after the reaction. However, the catalytic performance could not be attributed to the Au shell surface, but rather to the formation of a transient reconstructed alloy surface, promoted by CO adsorption during the reaction. The discovery of such a reversible transformation urges us to reconsider the reaction mechanism beyond the stationary model, and may have important implications not only for core–shell nanoparticles, but also for other well-defined nanocatalysts.
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Science Bulletin
·
2020
·
IF 9.511
Hong-Hui Wang,Shi-Nan Zhang,Tian-Jian Zhao,Yong-Xing Liu,Xi Liu,Juan Su,Xin-Hao Li,Jie-Sheng Chen
The direct hydrogenation of CO 2 using H 2 gas is a one-stone-two-birds route to produce highly value-added hydrocarbon compounds and to lower the CO 2 level in the atmosphere. However, the transformation of CO 2 and H 2 into hydrocarbons has always been a great challenge while ensuring both the activity and selectivity over abundant-element-based nanocatalysts . In this work, we designed a Schottky heterojunction composed of electron-rich MoC nanoparticles embedded inside an optimized nitrogen-doped carbon support (MoC@NC) as the first example of noble-metal-free heterogeneous catalysts to boost the activity of and specific selectivity for CO 2 hydrogenation to formic acid (FA) in liquid phase under mild conditions (2 MPa pressure and 70 °C). The MoC@NC catalyst with a high turnover frequency (TOF) of 8.20 mol FA mol MoC −1 h −1 at 140 °C and an excellent reusability are more favorable for real applications.
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 36
·49068
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IF 2.52
Bing Liu,Dan Li,Jie Yao,Hao Sun
Branched polyethyleneimine (PEI) functionalized UiO-66 were synthesized and used as fillers to fabricated mixed-matrix membranes (MMMs) for CO 2 /CH 4 separation. The purpose of introducing amino-functional groups in the filler is to improve the interfacial compatibility of the filler with the polymer through the formation of hydrogen bonds with the carbonyl group of 6FDA-ODA. Additionally, the amino group can facilitate CO 2 transport through a reversible reaction, enhancing the CO 2 /CH 4 separation properties of MMM. The chemical structure and morphology of fillers and membranes were characterized by employing X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), thermogravimetric (TGA), Derivative thermogravimetry (DTG) and scanning electron microscope (SEM). Furthermore, the effects of filler loading and feed pressure on CO 2 permeability and CO 2 /CH 4 selectivity have been investigated. MMMs present higher gas separation performance than pure 6FDA-ODA due to the presence of amino groups and the improvement of interface morphology. In particular, the MMM with 15 wt% loading of UiO-66-PEI shows optimum CO 2 permeability of 28.23 Barrer and CO 2 /CH 4 selectivity of 56.49. Therefore, post-synthetic modification of UiO-66 particle with PEI is a promising alternative to improved membrane performance.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Kai Wang,Yun Chen,Yangfeng Wang,Chu Liang,Hui Huang,Yongping Gan,Jun Zhang,Yang Xia,Xinping He,Wenkui Zhang
Facile, efficient, energy–saving and environmentally benign synthesis of carbon from CO 2 is desirable and critical for the large–scale utilization of greenhouse gas and carbon materials. Herein, a green, energy–saving and facile route is provided to efficiently synthesize carbon with various morphology and porosity via mechanochemical reaction of CO 2 with NaH. After 1 min ball milling, CO 2 is converted into hierarchical porous carbon . The morphology and porosity of as–synthesized carbon is found to strongly depend on ball milling conditions. The gas blowing effect and self–template of product of Na 2 CO 3 are responsible for the formation of hierarchical porous carbon. The buffering effect of Na 2 CO 3 and pores in and between carbon particles in repeated ball milling process is revealed as the key factor in determining the morphology and porosity of carbon, resulting in the morphology and porosity of carbons associated with ball milling conditions. This study provides a new avenue for green and energy–saving synthesis of carbon and efficient utilization of greenhouse gases.
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高影响因子
Environmental Progress & Sustainable Energy
·
2020
·Vol. 40
·期 1
·e13476
·
IF 1.989
Xinmin Liu,Xuexia Qiu,Xin Sun,Libin Mei,Lingyun Wang,Qingjie Guo
Organic amine adsorbents prepared by template method using ion exchange resin (D001) as support and polyethyleneimine (PEI) as a modifier, and the preparation process was optimized by orthogonal experiment plan. The results showed that adsorbents prepared under conditions (the copper ion concentration was 0.2 mol/L, the ultrasonic time was 3 hr, and the PEI loadings were 30%) had an excellent CO 2 adsorption properties. The effects of temperature and gas influent velocity on CO 2 adsorption properties were investigated in a fixed bed reactor. When PEI loadings were 30%, the adsorption temperature was 65°C and the gas influent velocity was 40 ml/min, organic amine adsorbents performed a better PEI dispersion, stability, and CO 2 adsorption capacity. Maximum CO 2 adsorption capacity was 4.00 mmol/g. Besides, the CO 2 adsorption capacity decreased by only 10% after 10 cycles of adsorption–desorption tests, attribute to a small amount of PEI was volatilize during the regeneration process. The external diffusion was eliminated by increasing the gas influent velocity, and the adsorption data were well fitted the Weber-Morris particle diffusion model, indicating that CO 2 adsorption was controlled by internal diffusion.
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高影响因子
Journal of Materials Chemistry A
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2020
·Vol. 8
·期 29
·14799-14806
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IF 11.301
Zhe Li,Ma-Lin Li,Xiao-Xue Wang,De-Hui Guan,Wan-Qiang Liu,Ji-Jing Xu
Severe polarization triggered by the limited electrochemical activity of carbon dioxide as well as the insulating and insoluble discharge product Li2CO3 significantly impedes the practical application of Li–CO2 batteries. Herein, a light-assisted Li–CO2 system employing SiC/RGO as the photo-electro-catalytic hybrid cathode is presented to overcome the obstacle of polarization in conventional Li–CO2 cells. RGO is capable of transferring high-energy electrons generated on SiC after absorbing photons, inhibiting the recombination of photogenerated electrons. During the discharge process, the kinetics of CO2 reduction reaction is promoted by the photogenerated electrons. Thus, the discharge voltage of the battery is increased to 2.77 V, which is very close to the theoretical potential for 4Li + 3CO2 → 2Li2CO3 + C (2.80 V). Besides, the holes generated on the photoelectrode upon charging promote the decomposition of Li2CO3, effectively alleviating the overpotential of the Li–CO2 battery. Consequently, the system exhibits an excellent energy efficiency of 84.4%. These findings demonstrate the promising potential of the photo-assisted electrochemical process in addressing the overpotential issue of Li–CO2 batteries.
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 29
·12522-12530
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IF 3.288
Yongdong Chen,Qiang Tang,Zhongbin Ye,Yue Li,You Yang,Haoyu Pu,Gao Li
In this paper, a series of ZnxCe1−xO2 (x = 0.00, 0.05, 0.10, 0.15, and 0.20) nanoparticles were synthesized via an aqueous-phase coprecipitation method. The ZnxCe1−xO2 nanoparticles were coated on honeycomb ceramics to prepare monolithic catalysts, and the catalytic activity of the monolithic catalysts was investigated for the direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol in a continuous tubular fixed-bed reactor. The as-prepared catalysts were fully characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/desorption isotherms, H2-temperature-programmed reduction (H2-TPR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and CO2-temperature-programmed desorption (CO2-TPD). The characterization results showed that doping Zn ions into the ceria lattice formed a fluorite-like solid solution and modified the structure and surface properties of the catalysts. Among all the monolithic ZnxCe1−xO2 catalysts, the monolithic Zn0.10Ce0.90O2 catalyst showed the highest catalytic activity with a methanol conversion of 20.5% with DMC selectivity of 82.1% at 160 °C and 2.4 MPa in the absence of any dehydrating agents. This superior catalytic activity was mainly attributed to a series of better properties, such as larger specific surface area (i.e. 179.9 m2 g−1), higher oxygen vacancy concentration, and the unique structure of the monolithic catalyst (e.g., removing by-product of water in time). This study provides a valuable design strategy for highly efficient direct synthesis of DMC using monolithic catalysts in the fixed-bed reactor.
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JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Zihan Qu,Rui Zhao,Hong Wu,Yanxiong Ren,Yutao Liu,Zheyuan Guo,Yingzhen Wu,Leixin Yang,Xu Liang,Zhongyi Jiang
High-performance membrane materials are urgently demanded for efficient membrane-based biogas upgrading. Polyelectrolytes with convertible ionic groups, spontaneously forming interconnected facilitated transport pathways for gas molecules via microphase separation , exhibit promising potential in membrane-based separation. However, there is a great challenge to further enhance the gas permeability and selectivity simultaneously due to the limited microphase separation and low free volume generated by the strong interaction between ionic groups. Herein, we demonstrate a novel strategy to construct the tunable hollow quaternary ammonium (-N + (CH 2 CH 3 ) 3 ) clusters with good CO 2 affinity via sacrificial template method in quaternized polysulfone (QAPSf) membranes for achieving the fast transport of CO 2 . The templates (POSS) induce the formation of –N + (CH 2 CH 3 ) 3 clusters through forced microphase separation in the membranes and then are etched away to generate hollow CO 2 -philic clusters to increase the fractional free volume in membranes and thus improve CO 2 diffusion. After that, the B(OH) 4 - as counterions by ion exchange endow the hollow CO 2 -philic clusters with high CO 2 -facilitating ability, which simultaneously enhance the CO 2 permeability and CO 2 /CH 4 selectivity. The resultant QAPSf-B(POSS-2) membrane exhibits superior separation performance with an optimal permeability of 1113 Barrer and a CO 2 /CH 4 gas selectivity of ~45, i.e. 334% and 73% higher than the pristine QAPSf membrane, respectively, breaking the trade-off between permeability and selectivity and surpassing the Robeson 2008 upper-bound.
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高影响因子
Journal of Energy Chemistry
·
2020
·
IF 7.216
Kuncan Wang,Wen Li,Junjie Huang,Jiale Huang,Guowu Zhan,Qingbiao Li
The extraction of metallic nanoparticles from perovskite-type oxides (ABO 3 ) under mild reducing conditions is a novel way to prepare well-dispersed supported catalysts (B/AO δ ). Herein, we found that the encapsulated PdO in perovskite LaCoO 3 (PdO@LaCoO 3 ) could facilitate the phase transformation of the perovskite structure at a low temperature owing to both strong H 2 spillover of Pd and intimate interaction between the encapsulated PdO and LaCoO 3 . The pure LaCoO 3 without PdO was relatively inert to CO 2 hydrogenation (CO 2 conversion <4%). In contrast, PdO@LaCoO 3 exhibited excellent CO 2 methanation performance with 62.3% CO 2 conversion and >99% CH 4 selectivity. The characterization results demonstrated that the catalytically active Co 2 C was in-situ formed by carburization of the extracted Co 0 during CO 2 methanation for the PdO@LaCoO 3 sample. Whereas, the LaCoO 3 with surface supported PdO (PdO/LaCoO 3 ) showed a weak interaction and remained a perovskite structure with few Co 2 C active centers after the catalytic reaction, which was similar to the parent LaCoO 3 . Accordingly, the PdO/LaCoO 3 showed an inferior catalytic performance with 31.8% CO 2 conversion and 87.4% CH 4 selectivity. Therefore, the designed encapsulation structure of PdO within perovskite is critical to extract metallic NPs from perovskite-type oxides, which has the potential to prepare other integrated nanocatalysts based on perovskite-type oxides.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 12
·9057-9064
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IF 2.22
Zhao Jingkui,Liu Xiansong,Kan Xucai,Chen Zuhua,Liu Chaocheng,Wang Wei,Lv Qingrong,Huang Jingwen,Shazeda Mudssir
In this study, novel Ni–Cu–Zn ferrites with the chemical formula [Ni 0.6 Zn 0.4 ][Cu 0.2 Co x Fe 1.8− x ]O 4 ( x = 0, 0.05, 0.10, 0.15, 0.20, 0.25) doped with Co 2+ ions were designed and manufactured by standard solid-state reaction method. The magnetic properties, surface characteristics, and ion occupancy of ferrites were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM), and we explained the different mechanisms of the results and the relationship between magnetic properties and microstructures. For the obtained samples, cobalt ions entered the lattice, and all samples were characterized as spinel structures. As the doping amount of Co 2+ ions increases, the lattice constant and volume of the sample also increases. With an appropriate doping level, Co 2+ ions-doped Ni–Cu–Zn ferrites can maintain higher saturation magnetization, higher magnetic permeability, and lower hysteresis loss. When x ≤ 0.1, the saturation magnetization M s increases significantly as the doping amount of Co 2+ ions increases, but when x > 0.1, the value decreases. The experimental results show that the saturation magnetization value is 118.08 emu/g, the magnetic permeability value is 39.47 H/m, and the hysteresis loss is 1.192 mW/cm 3 at an optimum doping amount. Therefore, the sample achieves the best magnetic properties when the doping amount is 0.1.
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高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Mengde Li,Junjie Liu,Shuping Deng,Qian Liu,Ning Qi,Zhiquan Chen
In this paper, three kinds of zeolite imidazole frameworks (ZIF-90, ZIF-93, and ZIF-94) were synthesized through hydrothermal reactions. Positron lifetime results reveal two kinds of pores corresponding to the channel in the windows and central cavity of ZIFs. The average diameters of the cavities are 1.12, 1.54, and 0.80 nm in ZIF-90, ZIF-93, and ZIF-94, respectively, while the average diameters of channels are between 0.55 and 0.60 nm. CO2 adsorption results show that ZIF-90 has the highest CO2 adsorption capacities (64.4 cm3 g–1 at 298 K and 104.7 cm3 g–1 at 273 K) at 1 bar, followed by ZIF-94 (57.9 cm3 g–1 at 298 K and 79.4 cm3 g–1 at 273 K) and ZIF-93 (41.5 cm3 g–1 at 298 K and 62.5 cm3 g–1 at 273 K). This shows inconsistency with the total pore volume but is in good agreement with relative volumes of pores smaller than 1.2 nm, which are 6.55, 2.06, and 5.60% for ZIF-90, ZIF-93, and ZIF-94, respectively. Further investigation reveals that an even smaller pore size is required for CO2 adsorption under ultralow pressure. At a pressure of 0.1 bar, ZIF-94 exhibits an ultrahigh CO2 adsorption capacity (21.2 cm3 g–1 at 298 K and 32.1 cm3 g–1 at 273 K) compared with ZIF-93 (10.1 cm3 g–1 at 298 K and 14.9 cm3 g–1 at 273 K) and ZIF-90 (5.9 cm3 g–1 at 298 K and 11.6 cm3 g–1 at 273 K). These quantities coincide well with the relative volumes of pores smaller than 0.8 nm, which are 5.60, 2.06, and 1.18% for ZIF-94, ZIF-93, and ZIF-90, respectively. Our results demonstrate that at atmospheric pressure, CO2 molecules are more effectively captured by micropores, while at extremely low pressures, CO2 molecules are mainly enriched around ultramicropores such as the channels and small cavities in ZIFs.
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