ACS Applied Nano Materials
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2021
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IF 5.097
Minkang Li,Lina Zhang,Zhongzheng Zhang,Jialin Shi,Yuefeng Liu,Jiansong Chen,Nannan Sun,Wei Wei
Integration of adequate activity, stability, and productivity in a catalyst is of strategical importance to achieve high performance, particularly for inactive reactants, e.g., CO2. Here, using a reversed microemulsion method, ultrafine metallic Ag nanoparticles coated with porous SiO2 can be facilely obtained using micelles as separated nanoreactors for the preparation. Such architectures allowed the rigid SiO2 matrices to act as physical spacers, so that aggregation of the Ag particles could be avoided. Meanwhile, due to the templating effect from the surfactant, large mesopores could be induced in the SiO2 shell, and thus the diffusion barrier of reactants could be minimized. When used as a heterogeneous catalyst for carboxylation of terminal alkynes by CO2 under mild conditions, the prepared xAg@SiO2 catalysts showed extraordinary performance in terms of excellent activity, stability, productivity, and wide substrate scope. The knowledge developed here may also enrich the toolbox for performance promotion of metal catalysts via specially fabricated structures.
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Journal of Environmental Chemical Engineering
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2021
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IF 5.909
Leizhi Zheng,Guoqiang Yang,Xingbang Hu,Zhibing Zhang
The capture and conversion of carbon dioxide (CO 2 ) into useful and valuable chemicals are receiving more and more research interesting. Herein, we designed a new and efficient route to synthesize methyl phenyl carbonate (MPC) via the carbonylation of phenol (PhOH) with CO 2 and methanol (CH 3 OH). PhOH and CH 3 OH react with 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) to form ionic liquids [DBUH][PhO] and [DBUH][CH 3 O]. The DBU-based ionic liquids exhibited outstanding performance in CO 2 capture and in situ conversion at room temperature. The reusability of the system had no obviously change after 6 cycles. This protocol provides a sustainable and environmentally friendly preferential technique for the production of MPC, and extends the chemical utilization of CO 2 .
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Catalysts
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2021
·Vol. 11
·期 4
·463
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IF 4.146
Zhenglong Yang,Yan Cui,Pengxiang Ge,Mindong Chen,Leilei Xu
The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO2methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce0.8Zr0.2O2solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO2. The catalysts were characterized systematically by X-ray powder diffraction (XRD), N2physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H2temperature programmed reduction (H2-TPR), CO2temperature programmed desorption (CO2-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal-skeleton interaction. Therefore, under the condition of CO2methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO2. In addition, the rare earth elements also act as electron modifiers to help activate CO2molecules. Therefore, the rare earth doped Ni-based mesoporous Ce0.8Zr0.2O2solid solution catalysts are expected to be an efficient catalyst for the methanation of CO2at low-temperature.Keywords:Ni-based catalyst;mesoporous Ce0.8Zr0.2O2solid solution;rare earth doped;low-temperature catalytic activity;CO2methanation
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Lei Xue,Aiai Zhang,Jinfang Wu,Qi Wang,Yang Liu,Yuansong Zhao,Shangpeng Liu,Ze Liu,Ping Li,Shanghong Zeng
Surface chemistry can be modified by introducing another component on the surface of catalyst due to the regulation of configuration and electronic properties. Herein, the nanostructured ZnO hollow microspheres were fabricated for selective CO 2 reduction to CO. The addition of CuO weakens the strength of adjacent Zn-O bond and improves the formation of more zero-valence Zn. Small CuO entities can provide the active sites for CO 2 adsorption, and the presence of surface defects due to Zn 2+ reduction could enhance initial dissociation from CO 2 to CO. More interestingly, the 3CuO/ZnO catalyst underwent reconstruction during electrocatalysis , and multi-shelled hollow spheres evolved into a thin flaky structure. The extended surface area of flaky morphology enhances the catalytic stability despite the occurrence of ZnO reduction. This study highlights the importance of surface modification for CO 2 selective reduction to CO but also provides some insights on reconstruction during electrochemical reduction of CO 2 .
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International Journal of Greenhouse Gas Control
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2021
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IF 3.738
Qiangwei Li,Ge Gao,Rujie Wang,Shihan Zhang,Shanlong An,Lidong Wang
Biphasic solvents are promising candidates for CO 2 capture for low regeneration energy consumption. In this study, a novel phase splitter 1-methylimidazole (1-MI) was proposed for triethylenetetramine (TETA) aqueous solvent. 1-MI was proved to act as a phase splitter to induce the phase separation and as an absorption promoter to enhance the absorption rate. By tuning the concentrations of TETA and 1-MI, good phase separation performance was obtained in TETA-1-MI biphasic solvent, achieving a CO 2 -rich phase loading of 5.41 mol/L. 13 C NMR revealed that the upper layer was the CO 2 -lean phase, containing 1-MI and a small amount of water, while the lower layer was the CO 2 -rich phase and mainly comprised of TETAH + and TETA-carbamate. The kinetics results based on the double-film theory indicated that the CO 2 absorption rate was mainly controlled by the gas film mass transfer resistance at lower CO 2 loading and then by liquid film mass transfer resistance when CO 2 loading was higher than 1 mol/L. Owing to the good phase separation behavior triggered by 1-MI, the regeneration heat of TETA-1-MI was 2.26 GJ/t CO 2 , which was comparable to that of the second-generation solvents, and 43.5 % lower than that of 5 M monoethanolamine (MEA). The present findings indicated that TETA-1-MI had a large loading capacity, high absorption rate, and low energy consumption, which can serve as a novel candidate for CO 2 capture.
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CHINESE JOURNAL OF CATALYSIS
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2021
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IF 8.271
Fang Li,Xiaoyang Yue,Haiping Zhou,Jiajie Fan,Quanjun Xiang
The active site amount of photocatalysts, being the key factors in photocatalytic reactions, directly affects the photocatalytic performance of the photocatalyst. Pristine graphitic carbon nitride (g-C 3 N 4 ) exhibits moderate photocatalytic activity due to insufficient active sites. In this study, cyano-modified porous g-C 3 N 4 nanosheets (MCN-0.5) were synthesized through molecular self-assembly and alkali-assisted strategies. The cyano group acted as the active site of the photocatalytic reaction, because the good electron-withdrawing property of the cyano group promoted carrier separation. Benefiting from the effect of the active sites, MCN-0.5 exhibited significantly enhanced photocatalytic activity for CO 2 reduction under visible light irradiation. Notably, the photocatalytic activity of MCN-0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid (HCl) treatment, further verifying the role of cyano groups as active sites. The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction. Furthermore, the controlled experiments showed that g-C 3 N 4 grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity, which proved the versatility of the strategy for enhancing the activity of g-C 3 N 4 via cyano group modification. In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO 2 reduction by cyano-modified g-C 3 N 4 . This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.
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RSC Advances
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2021
·Vol. 11
·期 28
·17197-17205
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IF 3.361
Bin Liu,Yanling Wang,Lei Liang,Yijin Zeng
Supercritical carbon dioxide (SC-CO2) fracturing technology has the characteristics of a large amount of fixed CO2 and anhydrous fracturing. It has great application potential for developing unconventional oil and gas resources and mitigating the greenhouse effect. However, the low viscosity of SC-CO2 limits the development of this technology. In this work, HS series thickeners were prepared via a ring-opening polymerization and hydrosilylation reaction by a molecular simulation-aided design method. The simulation results of cohesive energy density, interaction energy, and radial distribution function are consistent with the visualization experimental results, which proves that HS (hyperbranched siloxane) series thickeners have excellent solubility in SC-CO2. HS-3 is the best thickener in the HS series. At 305.15 K and 10 MPa, 5 wt% HS-3 (60 s−1) increases the viscosity of SC-CO2 by 151 times, and the apparent viscosity is 3.024 mPa s. The apparent viscosity of SC-CO2 was positively correlated with the pressure and concentration but negatively correlated with the temperature and shear rate. The results indicate that it is feasible to introduce an aliphatic group and polysiloxane into a SC-CO2 thickener by hydrosilylation.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Chen Jin,Jian Sun,Yuning Chen,Yafei Guo,Donghui Han,Ruilin Wang,Chuanwen Zhao
Sawdust wastes were used as the low-cost feedstock to prepare porous carbons by KOH activation, and the preparation parameters were optimized via orthogonal experiment. Four main activation parameters (i.e., sawdust type, KOH/sawdust ratio, activation temperature and activation time) were investigated. It is found that activation temperature and KOH/sawdust ratio are the two most important parameters that affect the porous texture properties (specific surface area and micropore volume) of sawdust wastes-derived porous carbons. The optimal sawdust wastes-derived porous carbon possesses a high specific surface area of 1601 m 2 /g and a micropore volume of 0.75 cm 3 /g, therefore exhibiting a desirable CO 2 adsorption capacity of 4.25 mmol/g at 0 °C under ambient pressure. Comparatively, the sawdust wastes-derived porous carbon extrudates exhibit the inferior CO 2 adsorption capacity, dropping to 2.85–3.03 mmol/g. It is mainly attributed to the extrusion treatment and binder addition causing the collapse and blockage of the original porous structure, consequently increasing the CO 2 diffusion and adsorption resistance. However, the sawdust wastes-derived porous carbon extrudates possess the advantages of null pressure build-up, improved bulk density and high compress strength (7.3–12.3 MPa) considering the real application point of view.
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APPLIED SURFACE SCIENCE
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2021
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IF 6.707
Pengyan Li,Li Liu,Weijia An,Huan Wang,Wenquan Cui
Photocatalytic CO 2 reduction is a potential way to address simultaneously environmental pollution and energy shortage. However, the difficulties of CO 2 activation and C C coupling lead to quite low conversion efficiency of CO 2 to C2 products. In this study, we constructed Cu 2 O/g-C 3 N 4 heterojunction for photocatalytic CO 2 reduction to ethanol by coupling thermal field and ionic liquids (ILs). The ethanol rate reached 0.71 mmol·g −1 ·h −1 over Cu 2 O/g-C 3 N 4 under photothermalcatalysis, which is 1.89 times that of photocatalysis and 7.05 times that of thermal catalysis. The temperature enhanced thermal motion of the radical, which promotes the formation of ethanol through the ·CH 3 dimerization. The 1-aminopropyl-3-methylimidazolium bromide ILs shows superior CO 2 reduction performance with a high current density (21.3 mA·cm −2 ) than KHCO 3 electrolyte (12.8 mA·cm −2 ). The overpotential is reduced by 0.34 V, which accelerates CO 2 reduction by reducing polarization. It is found that the ILs played a key role in suppressing H 2 O reduction and increasing ethanol yield in this photothermalcatalytic strategy.
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Sustainable Energy & Fuels
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2021
·Vol. 5
·期 17
·4295-4310
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IF 6.367
Ke Gao,Xianglei Liu,Tong Wang,Zhonghui Zhu,Ping Li,Hangbin Zheng,Chao Song,Yimin Xuan,Yongliang Li,Yulong Ding
Solar thermochemical CO2-to-fuel conversion via two-step redox cycles is a promising strategy to solve climate change and energy storage challenges simultaneously. However, ideal thermochemical materials possessing moderate operation temperature, high yield, good stability, and rapid kinetics operating under isothermal and near-isothermal conditions are still missing. Here, we propose Sr-doped SmMnO3 for moderate-temperature near-isothermal CO2-to-fuel conversions. A record-high isothermal cycle CO yield (376.1 μmol g−1) at no more than 1300 °C is reported based on Sm0.6Sr0.4MnO3. No obvious decay is observed during 14 cycles although grain sizes have increased to some extent. The weakened Mn–O bond induced by Sr doping helps to create more oxygen vacancies, and thus contributes to enhanced yield of both O2 and CO. The oxidation reaction is fast with a CO yield of 58.6 μmol g−1 in 15 minutes, which is 5.6 times as high as that of CeO2 under the same cycling conditions between 1300 °C and 1000 °C. Detailed kinetics for the oxidation step is unveiled based on the Šesták–Berggren model. In addition, SmxSr1−xMnO3 can capture full-spectrum solar energy with a solar absorptance of more than 86.6% in stark contrast to 13.5% for CeO2, making the required concentration ratio to drive reactions decrease by 33.4%. This work provides new materials for high yield and stable thermochemical CO2-to-fuel conversion under moderate-temperature near-isothermal conditions, and paves the way for the development of CO2 splitting techniques directly driven by low-concentration solar energy with high efficiencies.
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高影响因子
RENEWABLE ENERGY
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2021
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IF 8.001
Naveed Ahmad,Xiaoxiao Wang,Peixu Sun,Ying Chen,Fahad Rehman,Jian Xu,Xia Xu
Electrocatalytic CO 2 reduction (ECO 2 R) is an environment-friendly way to convert CO 2 into profitable products. Amine solution recently has been employed as an electrolyte in ECO 2 R but suffers from low efficiency. Herein, aqueous solutions containing different amine-based deep eutectic solvents (DESs) were used as electrolytes for CO 2 reduction. The effect of different DESs on the CO 2 reduction was investigated at Ag, Cu, and Zn metal electrodes. Tafel and electrochemical impedance spectroscopy (EIS) were applied to understand the CO 2 reduction. DES in aqueous solution facilitates the CO 2 reduction to CO with higher faradaic efficiency of CO (FE CO ) than amine solutions and a mixture of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Both HBD and HBA have an influence on CO 2 reduction. [Monoethanolamine hydrochloride] [methyldiethanolamine] ([MEAHCl][MDEA]) gives high FE CO , 71% FE CO at −1.1 V vs RHE at Ag electrode, 33% higher than [MEAHCl][MEA]. Experimental results and EIS analysis reveal that the facilitation of CO 2 reduction to CO probably stems from a synergistic effect of nano-size agglomerate dispersion on Ag-surface, bicarbonate formation, exchange current density , and Cl − ions present in DESs. These findings present a feasible method to employ the aqueous MDEA-based DES solution as an electrolyte for CO 2 reduction.
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FUEL PROCESSING TECHNOLOGY
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2020
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IF 4.982
Muhammad Masood Khan,Lijun Jin,Muhammad Mahmood Khan,Yang Li,Hammad Saulat,Yun Zhang,Muhammad Sarfraz,Jialong Zhu,Haoquan Hu
The composite catalysts AC-Ni/MgO-Al 2 O 3 were prepared by the co-precipitation method with activated carbon (AC) and [Ni,Mg,Al]-hydrotalcite as the precursors, and characterized by XRD , TG-DTG, N 2 adsorption, H 2 -TPR and SEM, respectively. The resultant catalysts were examined for CO 2 reforming of methane. The results showed that the introduction of AC into Ni/MgO-Al 2 O 3 catalyst improved the textural properties, especially the surface area and pore volume of mesopores , and decreased the size of metal Ni. Compared with Ni/MgO-Al 2 O 3 , the composite AC-Ni/MgO-Al 2 O 3 exhibited higher catalytic activity , stability and H 2 /CO ratio. But the AC content obviously influenced the catalytic performances. High AC loading resulted in the decline of catalytic activity owing to lower surface area and fewer active Ni content in the catalyst. 10AC-Ni/MgO-Al 2 O 3 with 10% AC displayed the best catalytic activity and stability compared with Ni/MgO-Al 2 O 3 . About 86.2% conversion of CH 4 , 91.3% conversion of CO 2 and above 0.95 ratio of H 2 /CO were achieved over 10AC-Ni/MgO-Al 2 O 3 sample for the reaction time of 5430 min. This work provides a route to improve catalytic performances of Ni-based catalysts in CO 2 reforming of methane.
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