INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Yijiao Qiu,Houfang Lu,Yingming Zhu,Yingying Liu,Kejing Wu,Bin Liang
Phase-change solvents exhibit the promising potential to reduce the regeneration energy for CO2 capture. In this paper, 3-dimethylaminopropylamine (DMAPA) with intramolecular primary and tertiary amino groups was mixed with solvent NHD and water for phase-change absorption of CO2 in the model flue gas. The results show that the homogeneous mixture changes into two phases after CO2 absorption when NHD/H2O ranges from 9:1 to 5:5 and 90% of CO2 is enriched in the lower phase with only 23% of the total volume. The absorption loading reaches 1.06 mol CO2/mol amine, the phase separation time for DMAPA–NHD–H2O is only 14% of that for MEA–SA–H2O, and the viscosity of the lower phase is only 37.14 mPa·s when DMAPA and NHD/H2O are 1 M and 8:2, respectively. Analysis of the reaction mechanism shows that the primary amino group of DMAPA initially reacts with CO2 and the tertiary amino group captures proton of zwitterionic intermediate as an acceptor. The mixed-amine effect is suggested to explain the high absorption performance of the DMAPA–NHD–H2O mixture. The energy estimation shows that the regeneration energy is reduced by 42% compared with that of the 5 M MEA solution, which confirms the advantage of phase-change absorption using DMAPA–NHD–H2O.
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Journal of Energy Chemistry
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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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CHEMICAL ENGINEERING JOURNAL
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2020
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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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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Xiaojiang Li,Li Wang,Hongsheng Lu,Baogang Wang
Recontamination or the difficult recovery of additives are the serious obstacle to separate emulsified oily wastewater, which may cause many health and ecological problems. Herein, the sustainable separation of emulsified oily wastewater was proposed by homogeneous extraction based on CO 2 switchable solution, where there was no pollution caused by additives. Here, CO 2 switchable solution is the bicarbonate solution that was prepared with the switchable solvent and water upon CO 2 . In terms of treating emulsified oily wastewater, the CO 2 switchable solution investigated exhibits the best effects on separating diesel oil or crude oil- emulsified wastewater, compared with flocculation and solvent extraction . Moreover, it was also applied in separating oily wastewater emulsified by hexadecyl ammonium bromide (CTAB) or emulsifier OP-10. After treated with CO 2 switchable solution [DMCHAH][HCO 3 ] (bicarbonate solution of N,N-Dimethylcyclohexylamine) upon N 2 /65 °C, the obvious oil-water phase separation was observed in oily wastewater. Then the oil was obtained and the [DMCHAH][HCO 3 ] was recovered after bubbling CO 2 into the oil phase. By detecting interface tension and microscopy images of oily wastewater, it is concluded that the separation of oily emulsified wastewater is caused by expansion behavior and the coalescence of emulsified oil droplets, which is induced by the reversible transformation from [DMCHAH][HCO 3 ] with hydrophilicity to DMCHA (N,N-Dimethylcyclohexylamine) with hydrophobicity . The sustainable treatment may provide a greener and economical approach for separating oil wastewater.
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JOURNAL OF MEMBRANE SCIENCE
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2020
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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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ENERGY & FUELS
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2020
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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 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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APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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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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GREEN CHEMISTRY
·
2020
·Vol. 22
·期 15
·5059-5066
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IF 9.48
Kaihang Sun,Ning Rui,Zhitao Zhang,Zeyu Sun,Qingfeng Ge,Chang-Jun Liu
Supported Pt catalysts have been extensively investigated for CO2 hydrogenation with methane and CO as the principal products. In this work, a Pt/In2O3 catalyst prepared with decomposition precipitation was tested for CO2 hydrogenation to methanol. The Pt/In2O3 catalyst exhibited a highly improved activity towards CO2 hydrogenation, with methanol selectivity of ca. 100% at temperatures below 225 °C, 74% at 275 °C and 54% at 300 °C, respectively, compared to the pure In2O3 catalyst. This represents the highest methanol selectivity reported on Pt catalysts for CO2 hydrogenation. The stability of the Pt/In2O3 catalyst at elevated temperatures has also been higher than that of the pure In2O3 catalyst, indicated by the methanol formation rate decreasing only to 95% of the initial rate after 5 h in the reaction stream and remaining largely constant thereafter. In contrast, the pure In2O3 catalyst loses 20% of the initial methanol formation rate after 9 h in the reaction stream. The characterization of the catalysts confirms that the Pt nanoparticles are well dispersed on In2O3 with a particle size below 3 nm. The strong metal–support interaction (SMSI) between Pt and In2O3 improves the stability of the catalyst and prevents the over-reduction of In2O3. The synergy between the supported Pt nanoparticles and In2O3 balances the hydrogen activation and the density of the surface oxygen vacancies in In2O3, resulting in the high activity for CO2 hydrogenation and enhanced stability of the Pt/In2O3 catalyst.
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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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ChemSusChem
·
2020
·Vol. 13
·期 18
·4900-4905
·
IF 7.962
Yingliang Yang,Hongshuai Gao,Jiaqi Feng,Shaojuan Zeng,Lei Liu,Licheng Liu,Baozeng Ren,Tao Li,Suojiang Zhang,Xiangping Zhang
Graphical CO 2 electroreduction : An aprotic aromatic ester-functionalized ionic liquid (IL), [TEA][4-MF-PhO], is designed for CO 2 electroreduction to oxalic acid. The multiple active sites exhibit excellent catalytic performance with high current density and faradaic efficiency by interacting with CO 2 . This study provides a promising prospect for using IL as electrolyte to develop efficient electrocatalysts. Electrochemical reduction of CO 2 into valuable chemicals is a significant route to utilize CO 2 resources. Among various electroreduction products, oxalic acid (H 2 C 2 O 4 ) is an important chemical for pharmaceuticals, rare earth extraction, and metal processing. Here, an aprotic aromatic ester-functionalized ionic liquid (IL), 4-(methoxycarbonyl) phenol tetraethylammonium ([TEA][4-MF-PhO]), was designed as an electrolyte for CO 2 electroreduction into oxalic acid. It exhibited a large oxalic acid partial current density of 9.03 mA cm −2 with a faradaic efficiency (FE) of 86 % at −2.6 V (vs. Ag/Ag + ), and the oxalic acid formation rate was as high as 168.4 μmol cm −2 h −1 , which is the highest reported value to date. Moreover, the results of density functional theory calculations demonstrated that CO 2 was efficiently activated to a −COOH intermediate by bis-active sites of the aromatic ester anion via the formation of a [4-MF-PhO-COOH] − adduct, which finally dimerized into oxalic acid.
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PubMed
高影响因子
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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