JOURNAL OF SUPERCRITICAL FLUIDS
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2021
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IF 4.577
Jian-Lei Qi,Qin-Qin Xu,Dan Zhou,Jian-Zhong Yin,Qi-Ke Jiang
Cu single atoms dispersed on N-doped carbon materials (Cu-NC) were obtained after supercritical CO 2 deposition and decompression, without further post-treatment. AC-HAADF-STEM, STEM , XRD , ICP-OES, and XPS results confirmed that the Cu atoms were equably dispersed over the N-doped carbon (NC) support with the loading of 0.80 wt%. The catalytic performance of Cu-NC in solvent-free oxidation of phenylcarbinol to benzaldehyde was investigated, and the conversion of 73.9% and selectivity of 85.7% were obtained at 50 °C for 1 h. A high-pressure view cell was used to observe the dissolution and diffusion for Cu(acac) 2 in scCO 2 . The stability of Cu-NC structures and the formation path of active oxygen species (O*) on different configurations were predicted by density functional theory (DFT) calculations, and CuN 3 C 1 was found to be more conducive to the activation of tert-butyl hydroperoxide (TBHP).
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Nature Communications
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2021
·Vol. 12
·期 1
·1-11
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IF 14.919
Wang Jia-Wei,Jiang Long,Huang Hai-Hua,Han Zhiji,Ouyang Gangfeng
The fulfillment of a high quantum efficiency for photocatalytic CO 2 reduction presents a key challenge, which can be overcome by developing strategies for dynamic attachment between photosensitizer and catalyst. In this context, we exploit the use of coordinate bond to connect a pyridine-appended iridium photosensitizer and molecular catalysts for CO 2 reduction, which is systematically demonstrated by 1 H nuclear magnetic resonance titration, theoretical calculations, and spectroscopic measurements. The mechanistic investigations reveal that the coordinative interaction between the photosensitizer and an unmodified cobalt phthalocyanine significantly accelerates the electron transfer and thus realizes a remarkable quantum efficiency of 10.2% ± 0.5% at 450 nm for photocatalytic CO 2 -to-CO conversion with a turn-over number of 391 ± 7 and nearly complete selectivity, over 4 times higher than a comparative system with no additional interaction (2.4%±0.2%). Moreover, the decoration of electron-donating amino groups on cobalt phthalocyanine can optimize the quantum efficiency up to 27.9% ± 0.8% at 425 nm, which is more attributable to the enhanced coordinative interaction rather than the intrinsic activity. The control experiments demonstrate that the dynamic feature of coordinative interaction is important to prevent the coordination occupancy of labile sites, also enabling the wide applicability on diverse non-noble-metal catalysts.
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ADVANCED FUNCTIONAL MATERIALS
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2021
·Vol. 31
·期 27
·2101255
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IF 18.808
Henglei Jia,Yuanyuan Yang,Tsz Him Chow,Han Zhang,Xiyue Liu,Jianfang Wang,Chun-yang Zhang
Symmetry-breaking synthesis of colloidal nanocrystals with desired structures and properties has aroused widespread interest in various fields, but the lack of robust synthetic protocols and the complex growth kinetics limit their practical applications. Herein, a general strategy is developed to synthesize the Au–Cu Janus nanocrystals (JNCs) through the site-selective growth of Cu nanodomains on Au nanocrystals, which is directed by the substantial lattice mismatch between them, with the assistance of judicious manipulation of the growth kinetics. This strategy can work on Au nanocrystals with different architectures for the achievement of diverse asymmetric Au–Cu hybrid nanostructures. Of particular note, the obtained Au nanobipyramids (Au NBPs)-based JNCs facilitate the conversion of CO 2 to C 2 hydrocarbon production during electrocatalysis, with the Faradaic efficiency and maximum partial current density being 4.1-fold and 6.4-fold higher than those of their monometallic Cu counterparts, respectively. The excellent electrocatalytic performances benefit from the special design of the Au–Cu Janus architectures and their tandem catalysis mechanism as well as the high-index facets on Au nanocrystals. This research provides a new approach to synthesize various hybrid Janus nanostructures, facilitating the study of structure-function relationship in the catalytic process and the rational design of efficient heterogeneous electrocatalysts.
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APPLIED SURFACE SCIENCE
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2021
·
IF 6.707
Jianfei Xiao,Yuan Wang,Tian C. Zhang,Shaojun Yuan
Nitrogen-sulfur codoped porous carbon (NSPC) is a promising advanced material, showing great application potential in greenhouse gas capture and energy storage. Here, a novel NSPC with controllable porous structure was fabricated via pyrolysis and activation of N, -containing polycondensates, which were synthesized by one-pot polycondensation reaction of triglycidyl isocyanurate, glucose and thiourea. The obtained sample NSPC-1-650 showed cross-linked spherical morphology with uniform pore size (2.61 nm), large specific surface areas (1927.46 m 2 ·g −1 ), and the doping of nitrogen (4 wt%) and sulfur (2 wt%), which leaded to a good CO 2 adsorption capability (5.56 mmol·g −1 at 298.15 K, 5 bar) and excellent stability. Additionally, when used as a supercapacitor, the NSPC-1-650 sample showed an ultrahigh specific capacitance (224.3F·g −1 at 1 A·g −1 in 6 M KOH electrolyte), an excellent rate capability, and good stability (retained > 85% capacity after 5000 cycles). Notably, the all solid-state symmetrical NSPC-1-650-based supercapacitors delivered a high energy density (the maximal value = 7.8 Wh·Kg −1 ) and power density (the maximal value = 4500 W·Kg −1 ). These results suggest that NSPC-1-650 be a competitive candidate as a CO 2 adsorbent and supercapacitor.
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Catalysts
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2021
·Vol. 11
·期 5
·561
·
IF 4.146
Fangyuan Wang,Yu Liu,Zhiling Song,Zhichao Miao,Jinping Zhao
Electrochemical CO2reduction reaction (CO2RR) is eliciting considerable attention in relation to the carbon cycle and carbon neutrality. As for the practical application of CO2RR, the electrocatalyst is a crucial factor, but, even so, designing and synthesizing an excellent catalyst remains a significant challenge. In this paper, the coordination compound of Ni ions and dimethylglyoxime (DMG) was employed as a precursor to modify reduced graphene oxide (rGO) for CO2RR. The textural properties and chemical bonds of as-obtained rGO, N–C–rGO, Ni–rGO, Ni–N–C, and Ni–N–C–rGO materials were investigated in detail, and the role of Ni, N–C, and rGO in the CO2RR were researched and confirmed. Among all the catalysts, the Ni–N–C–rGO showed the optimal catalytic activity and selectivity with a high current density of 10 mA cm−2and FE(CO)% of 85% at −0.87 V vs. RHE. In addition, there was no obvious decrease in activity for 10 h. Therefore, the Ni–N–C–rGO is a promising catalyst for CO2RR to CO.Keywords:metallic Ni;N-doped carbon;reduced graphene oxide;electrocatalyst;electrochemical CO2reduction
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ENERGY & FUELS
·
2020
·
IF 3.421
Houxiao Wu,Yinuo Yuan,Yongwei Chen,Daofei Lv,Shi Tu,Ying Wu,Zhong Li,Qibin Xia
CO2 capture and storage technologies have been adopted to eliminate anthropogenic CO2 emission. Compared with other methods, adsorptive separation technology using excellent adsorbents has attracted extensive attention for its operational flexibility and energy-efficient characteristics. Herein, we present a copper-based metal–organic framework, MOF-11, exhibiting highly efficient CO2/N2 (15:85, v/v) separation performance. There are two kinds of channels with different pore chemistries in the framework, in which dense Cu open metal sites (OMS) were found in channel I, while channel II had a narrower pore window size and was mainly decorated with −CH2 moieties from the organic ligands. At 298 K, the CO2 uptake value of MOF-11 was 4.63 mmol/g at 100 kPa and 2.92 mmol/g at 15 kPa, respectively, which was superior to many other reported MOF adsorbents. Molecular simulation indicated that CO2 dominantly occupied channel I due to the strong electrostatic interactions with the dense Cu OMS in channel I. In comparison, more N2 molecules were adsorbed into channel II through multiple weak van der Waals interactions with −CH2 moieties. Such a pore system gives MOF-11 high CO2/N2 selectivity (ca. 116 at 298 K). Moreover, the dynamic separation of CO2/N2 mixture gases on MOF-11 was further investigated by cyclic breakthrough experiments.
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Frontiers in Microbiology
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2020
·
IF 4.236
Wang Xiaoshuai,Chen Lei,Liu Jing,Sun Tao,Zhang Weiwen
myo-inositol (MI) is an essential growth factor, nutritional source, and important precursor for many derivatives like D-chiro-inositol. In this study, attempts were made to achieve the “green biosynthesis” of MI in a model photosynthetic cyanobacterium Synechocystis sp. PCC 6803. First, several genes encoding myo-inositol-1-phosphate synthases and myo-inositol-1-monophosphatase, catalyzing the first or the second step of MI synthesis, were introduced, respectively, into Synechocystis. The results showed that the engineered strain carrying myo-inositol-1-phosphate synthase gene from Saccharomyces cerevisiae was able to produce MI at 0.97 mg L–1. Second, the combined overexpression of genes related to the two catalyzing processes increased the production up to 1.42 mg L–1. Third, to re-direct more cellular carbon flux into MI synthesis, an inducible small RNA regulatory tool, based on MicC-Hfq, was utilized to control the competing pathways of MI biosynthesis, resulting in MI production of ∼7.93 mg L–1. Finally, by optimizing the cultivation condition via supplying bicarbonate to enhance carbon fixation, a final MI production up to 12.72 mg L–1 was achieved, representing a ∼12-fold increase compared with the initial MI-producing strain. This study provides a light-driven green synthetic strategy for MI directly from CO2 in cyanobacterial chassis and represents a renewable alternative that may deserve further optimization in the future.
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PubMed
高影响因子
GREEN CHEMISTRY
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2020
·Vol. 22
·期 21
·7529-7536
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IF 9.48
Huihuang Chen,Xu Guo,Xiangdong Kong,Yulin Xing,Yan Liu,Bolong Yu,Qun-Xiang Li,Zhigang Geng,Rui Si,Jie Zeng
CO2 electroreduction into valuable products holds great promise for energy supply and environmental remediation but remains a challenge due to the lack of high-performance electrocatalysts. Herein, we developed an efficient strategy to prepare highly active Fe single-atom catalysts (Fe–N5/Fe–N6) by tuning the coordination number of Fe with N towards CO2 electroreduction. The faradaic efficiency of CO for Fe–N5 exceeded 90% ranging from −0.35 to −0.65 V versus the reversible hydrogen electrode (vs. RHE) towards CO2 electroreduction. The turnover frequency of CO for Fe–N5 reached 5006 h−1 at −1.05 V vs. RHE, which was 3.8 times that (1324 h−1) of Fe–N6. Besides, CO was generated at an overpotential as low as 50 mV over Fe–N5, smaller than that (90 mV) over Fe–N6. Density functional theory calculations demonstrated that Fe–N5 facilitated the adsorption and activation of CO2 to form the *COOH intermediate, thus leading to superior selectivity and activity for CO2 electroreduction.
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Arabian Journal of Chemistry
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2020
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IF 4.762
Kechen Song,Shuo Wang,Qiang Sun,Deping Xu
Nano-sheets Al 2 O 3 supported CeO 2 -Fe 2 O 3 binary oxides were prepared by the vacuum impregnation method. The structural and textural properties were characterized by pertinent techniques, and the materials were evaluated as catalysts for the oxidative dehydrogenation of ethylbenzene with carbon dioxide (CO 2 -ODEB). The characterization results show that all samples maintain the hierarchical structure, and CeO 2 -like and Fe 2 O 3 -like solid solutions were formed when changing the Ce-to-Fe molar ratio. The catalytic performances indicate that CeO 2 -Fe 2 O 3 binary oxides were effective for CO 2 -ODEB, and the activity is determined by mobile oxygen, which can facilitate the dehydrogenation process. The DFT studies further identified the reaction pathway and rate-determining step. The inter-transmission of oxygen species and the presence of CO 2 refill the oxygen vacancies and restore the redox cycle of CeO 2 -Fe 2 O 3 binary oxides.
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ENERGY & FUELS
·
2020
·
IF 3.421
Yu Li,Jinzhe Gao,Jinxiu Li,Younan Li,Matthew T. Bernards,Mengna Tao,Yi He,Yao Shi
While CO2 capture with nonaqueous solutions is a promising approach, regeneration of the solutions often requires high energy consumption. This energy consumption can be potentially reduced by microwave regeneration, the performance of which is strongly affected by the selection of solvent. Therefore, we investigated the characteristics of microwave regeneration for nine triethylenetetramine (TETA) solutions. The results show that the heating rate of a solution in the microwave was primarily affected by its viscosity, dielectric constant, and heat capacity. The desorption energy consumption of CO2-loaded solutions had a strong linear correlation with the dielectric constant of the solvents over a certain solvent viscosity range (1.4–88.8 mPa·s, 20 °C). A comparison of microwave heating and conductive heating shows that the former performs better when considering regeneration temperature, CO2 recovery, and energy requirement. Under the condition of 800 W, the energy consumption using microwave regeneration for 30 wt % TETA/BDO and TETA/PEG200 solutions decreased by 69% and 76%, while CO2 recovery increased by 2.6 and 2.7 times, respectively, compared to a 30 wt % monoethanolamine aqueous solution regenerated by conductive heating. Therefore, TETA with microwave regeneration represents a promising approach for CO2 capture and recovery.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
·
IF 7.489
Song He,Guanyu Chen,Huan Xiao,Guibin Shi,Chichi Ruan,Yuansheng Ma,Huaming Dai,Bihe Yuan,Xianfeng Chen,Xiaobing Yang
Activated carbons (AC) were prepared by carbonization and KOH activation using rice husk as feedstock. The effects of impregnation ratios and activation temperatures on the properties of AC were investigated. Under optimum conditions, BET surface area, total pore volume and micropore volume of AC are as high as 1495.52 m 2 /g, 0.786 cm 3 /g and 0.447 cm 3 /g, respectively. Surface modification with chitosan as nitrogen source was performed simultaneously during KOH activation process. XPS and FT-IR analyses show that N -species was successfully incorporate into AC. Compared with AC-5 (general AC), CAC-5 (modified AC) exhibits better CO 2 adsorption performance, reaching 5.83 mmol/g at 273 K and 1 bar, which can be attributed to the formation of the CO 2 -philic active sites on AC surface by N -species. The linear correlations between CO 2 uptake, micropore volume within specific size section and N -content was investigated. The isosteric heat of CO 2 adsorption for CAC-5 (average 30.21 kJ/mol) is much higher than that of AC-5 (average 14.48 kJ/mol). The adsorption behavior of CAC-5 can be well described by Freundlich model. The high IAST selectivity factor for N -doped ACs indicates their excellent adsorption selectivity for CO 2 over N 2 . Both physisorption and chemisorption are present in CO 2 adsorption process of N -doped ACs.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Mu Liu,Liren Zheng,Xiaolei Bao,Zeyan Wang,Peng Wang,Yuanyuan Liu,Hefeng Cheng,Ying Dai,Baibiao Huang,Zhaoke Zheng
Atomic layer deposition (ALD) technique has been proved to be an efficient method to synthesize or modify catalyst. In this study, Cu was loaded on different TiO 2 substrates, pristine TiO 2 and black TiO 2 (denoted as H-TiO 2 ) to achieve better CO 2 photocatalytic reduction performance. Both TiO 2 @Cu and H-TiO 2 @Cu exhibited dramatic enhancement for CO and CH 4 production. The peculiar phenomenon of TiO 2 outperforming H-TiO 2 after ALD loading was further studied by a series of characterization methods. Even though H-TiO 2 showed superior performance for photocatalytic CO 2 reduction than TiO 2 , pristine TiO 2 loaded with more Cu 0/+ after ALD deposition surpassed the performance of H-TiO 2 @Cu which possessed less amount of Cu 0/+ and more Cu 2+ . Cu 0/+ is proved to be the crucial factor for CO 2 reduction and it is capable of overshadowing the influence of Ti 3+ and V o . These results indicate that not only will ALD technique significantly enhance the CO 2 reduction performance after Cu deposition, but the substrate employed for loading and the chemical state of loaded material will also influence the subsequent catalytic performance. In addition, our result provides additional experiment evidence for justifying the significance of Cu 0/+ in photocatalytic CO 2 reduction reaction.
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