查找使用阿拉丁产品的科研文献

Aminosilane-functionalized Ti-based metal–organic framework for efficient and selective CO2 adsorption

Zhen Huang,Lingri Ying,Fengchun Gong,Jianfeng Lu,Weilong Wang,Jing Ding,Jinyue Yan

Carbon dioxide capture and storage (CCS) is considered as a promising strategy for reducing CO 2 emissions. However, the further development of CO 2 adsorption materials with high selectivity and high adsorption capacity is the top priority of this technology . In this study, we used the μ-OH sites of the MIL-125 metal–organic framework (MOF) to modify it with aminosilane to synthesize a new MOF adsorbent (SAP-MIL-125) with improved CO 2 adsorption capacity at room temperature. Although there are no open metal sites on the MIL-125 surface, it is possible to load aminosilanes onto it. Under the same adsorption conditions, the CO 2 adsorption by SAP-MIL-125 was significantly improved compared to that of the original MIL-125. Adsorption isotherm and kinetics models were used to clarify that the adsorption mechanism of CO 2 on SAP-MIL-125 was non-homogeneous layer chemisorption . SAP-MIL-125 has excellent selectivity toward CO 2 (compared to N 2 ) and good stability over five adsorption–desorption cycles. The adsorption of CO 2 by SAP-MIL-125 is a spontaneous exothermic process. An in-depth investigation of the adsorption mechanism suggests that the acid–base interactions of carbamates is the mechanism of CO 2 adsorption. Density functional theory and frontier molecular orbital calculations showed that the main adsorption sites for the modified adsorbent were nitrogen-containing groups on the surface of aminosilanes, with the primary amines having the highest affinity for CO 2 . In conclusion, a novel material modification method for MOFs is provided, which was used to fabricate a CO 2 adsorbent with great potential for development.

CO2 capture using EGHE-based water-lean solvents with novel water balance design

Qinghai Long,Shuo Wang,Shufeng Shen

Maintaining water balance in water-lean solvents is drawing special attention as it may affect the capture performance and process stability. In this study, novel water-lean solvents containing ethylene glycol monohexyl ether (EGHE) and secondary alkanolamines was proposed for energy-saving postcombustion CO 2 capture. Excess water from wet flue gas can be discharged from the desorber overhead condensate which can produce a spontaneous phase-separation feature. Less than 0.8 mass% EGHE was observed in the water-rich phase of the biphasic condensate. Effect of water content in these absorbents on CO 2 capture performance was discussed. Most notably, regeneration energy consumption increased significantly as increasing water content in the absorbent. The proposed water-lean absorbents with 10 % H 2 O can reduce the regeneration heat duty by about 40% in comparison with aqueous MEA, indicating that the novel water balance design can make it competitive in a practical sense.

An efficient way to use CO2 as chemical feedstock by coupling with alkanes

Changcheng Wei,Wenna Zhang,Kuo Yang,Xiu Bai,Shutao Xu,Jinzhe Li,Zhongmin Liu

ABSTRACT The most promising method to eliminate CO 2 is to find large-scale and value-added applications of CO 2 as a carbon resource. However, the utilization of CO 2 as feedstock for basic chemicals has long been a great challenge owing to its high thermodynamic stability. Herein, we report the coupling conversion of CO 2 with light alkanes over the HZSM-5 zeolite with much higher aromatic selectivity than light alkanes as the only reactant. A CO 2 conversion of 17.5% and n -butane conversion of 100% with aromatic selectivity of 80% could be achieved by the coupling reaction at the CO 2 to n -butane ratio of 0.475, in which CO 2 not only acted as an agent for balancing hydrogen in the reaction but also partly (~25%) incorporated into the aromatic products. Methyl-substituted lactones (MLTOs) and methyl-substituted cycloalkenones (MCEOs) were identified as key intermediates during the coupling reaction. 13 C isotope labeling experiments, 13 C solid-state NMR, in-situ diffuse reflectance infrared Fourier transform spectroscopy, and density functional theory (DFT)calculations revealed that CO 2 could react with carbonium ions generated from alkane cracking to form MLTOs, which could further get converted into MCEOs, thus generating aromatic compounds . This coupling reaction provides guidance for the direct utilization of CO 2 to produce value-added chemicals with the simultaneous transformation of light alkanes.

Atomically dispersed indium and cerium sites for selectively electroreduction of CO2 to formate

Liang Zhong,Song Lianpeng,Sun Mingzi,Huang Bolong,Du Yaping

Currently, single-atom combo catalysts (SACCs) for carbon dioxide reduction reaction (CO 2 RR) to the formation of HCOOH are still very limited, especially the lanthanide-based SACCs. In this work, the novel SACCs with atomically dispersed In and Ce active sites were successfully prepared on the nitrogen-doped carbon matrix (InCe/CN). Both aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) images and the extended X-ray absorption fine structure (EXAFS) spectra proved the well-isolated In and Ce atoms. The as-prepared InCe/CN shows a high Faradaic efficiency (FE) (77%) and current density of HCOOH formation ( j HCOOH ) at −1.35 V vs. reversible hydrogen electrode (RHE), much higher than the single atom catalysts. Theoretical calculations have indicated that the introduced Ce single atom sites not only significantly promote electron transfer but also optimize the In-5p orbitals towards higher selectivity towards the HCOOH formation. This work innovatively extends the design of SACCs towards the main group and Ln metals for more applications.

Modulating the Asymmetric Atomic Interface of Copper Single Atoms for Efficient CO2 Electroreduction

Pengyu Song,Botao Hu,Di Zhao,Jiantao Fu,Xiaoran Su,Wuyi Feng,Ke Yu,Shoujie Liu,Jiatao Zhang,Chen Chen

Cu single-atom catalysts (Cu SACs) have been considered as promising catalysts for efficient electrocatalytic CO2 reduction reactions (ECRRs). However, the reports on Cu SACs with an asymmetric atomic interface to obtain CO are few. Herein, we rationally designed two Cu SACs with different asymmetric atomic interfaces to explore their catalytic performance. The catalyst of CuN3O/C delivers high ECRR selectivity with an FECO value of above 90% in a wide potential window from −0.5 to −0.9 V vs RHE (in particular, 96% at −0.8 V), while CuCO3/C delivers poor selectivity for CO production with a maximum FECO value of only 20.0% at −0.5 V vs RHE. Besides, CuN3O/C exhibited a large turnover frequency (TOF) up to 2782.6 h–1 at −0.9 V vs RHE, which is much better than the maximum 4.8 h–1 of CuCO3/C. Density functional theory (DFT) results demonstrate that the CuN3O site needs a lower Gibbs free energy than CuCO3 in the rate-determining step of CO desorption, leading to the outstanding performance of CuN3O/C on the process of ECRR-to-CO. This work provides an efficient strategy to improve the selectivity and activity of the ECRR via regulating asymmetric atomic interfaces of SACs by adjusting the coordination atoms.

Polyethyleneimine-modified multi-walled carbon nanotubes mixed matrix membranes for CO2/N2 separation

Xingqian Wang,Yifei Wang,Yongjiang Shan,Xuerong Wang,Yingdong Yang,Fei Zhang,Xiangshu Chen

In recent years, membrane separation technology has received extensive attention in CO 2 /N 2 separation. Carbon nanotubes (CNTs) were regarded as ideal fillers for constructing high permeability mixed matrix membranes (MMMs) due to their special tubular structure. However, the interfacial compatibility between CNTs and organic polymer phases is a large challenge, seriously hindering the development of carbon-based mixed matrix membranes. In this work, we proposed a novel polyethyleneimine (PEI) surface functionalization strategy to effectively improve the compatibility between multi-walled carbon nanotubes (MWCNTs) and Pebax-1657. The as-prepared PEI@MWCNTs/Pebax-1657 MMMs were analyzed by XRD, EDS, FTIR, TG, etc. The PEI can improve the compatibility of MWCNTs with the polymer matrix. In addition, the abundant amino groups in the PEI structure can provide ample active sites for CO 2 , which can improve CO 2 permeability and CO 2 /N 2 selectivity simultaneously. Combining the low resistance of MWCNTs to gas transport, the membrane showed 178.08% enhancement in selectivity (82.06) of CO 2 /N 2 compared to the pristine membrane with 152.49% increment in the permeability (150.51 Barrer) of CO 2 . This work provides a novel strategy for preparing carbon-based mixed matrix membranes with high gas separation performance.

Silica-modulated Cu-ZnO-Al2O3 catalyst for efficient hydrogenation of CO2 to methanol

Hangjie Li,Liang Wang,Feng-Shou Xiao

Cu/ZnO/Al 2 O 3 catalyst has been widely studied in the hydrogenation of CO 2 to methanol, but it still suffers from insufficient catalyst stability and methanol selectivity. Herein, we overcome these issues by introducing the silica promoter to the catalyst, achieving the Cu/ZnO/Al 2 O 3 /SiO 2 (CZAS) catalysts with significantly improved methanol selectivity and catalyst durability. Characterizations of samples showed that the silica species efficiently hindered the sintering of Cu nanoparticles during the catalysis, exhibiting constant performances in the continuous tests. In addition, the silica also electronically modulated the Cu nanoparticles that result in abundant Cu δ+ species in the catalyst, which minimized the methanol decomposition to improve the methanol selectivity, compared with the silica-free Cu/ZnO/Al 2 O 3 catalyst. As a result, the CZAS exhibited CO 2 conversion at 12.6 % and methanol selectivity at 85.1 %, giving a one-pass methanol yield at 10.7 %. The strategy in this work might provide an efficient route for enhancing the current industrial catalysts.

Dual-atom Cu2/N-doped carbon catalyst for electroreduction of CO2 to C2H4

Guodong Sun,Yanan Cao,Deqing Li,Mingzhen Hu,Xinhu Liang,Zhe Wang,Zengjian Cai,Fengyi Shen,Bozhen Chen,Kebin Zhou

Electrochemical reduction of CO 2 to multi-carbon products is very attractive yet particularly challenging due to the low efficiency of C-C coupling over currently used electrocatalysts. In this work, we report a dual-atom catalyst (Cu 2 /NC) capable of selectively promoting electro-reduction of CO 2 to C 2 H 4 . The Faradaic efficiency of CO 2 -to-C 2 H 4 over the Cu 2 /NC is up to ∼34.9% with a current density of 33.6 mA·cm −2 . By contrast, its Cu single-atom counterpart only generates CO without forming C 2 H 4 . The density functional theory (DFT) calculations reveal that the Cu-Cu sites largely promote the adsorption of *CO and reduce the energy barrier of C-C coupling between the adsorbed *CO relative to that of the single Cu sites, which accounts for the high C 2 H 4 selectivity of the Cu 2 /NC.

Features of nanoparticle composite-enhanced CO2 foam-flooding systems for low-permeability reservoirs

Liu Yong,Zhao Fajun,Niu Ruixia,Cao Sheng,Liu Lei,Song Yarui

This study examined an enhanced foam-flooding system incorporating nanoparticles and polymers under geological conditions of a reservoir of the Shu 16 block in the Yushulin oilfield. The system is mainly comprised of an anionic foaming agent (CQS-1) and a nonionic surfactant (FH-1). We screened 17 foams by evaluating their foaming volumes and foam half-lives using a Waring-blender and dynamic foam analysis methods, and nanoparticles were selected after examining each foam’s concentration, the ratio of the main agent to the auxiliary agent, and the dosage of the foam stabilizer. Then, we analyzed the selected system’s microstructure and rheological properties, including the adaptability of the reservoir to its temperature resistance, salt tolerance, and adsorption resistance. As a result, this study supports the field application of CO2 foam flooding.

CO2-switchable surfactant-free microemulsion consisted of N,N-dimethylcyclohexylamine, ethanol and water

Daixue Xu,Hongsheng Lu,Dongfang Liu,Xiaojiang Li

Conversion of a surfactant-based microemulsion to a surfactant-free microemulsion by CO2

Dongfang Liu,Hongsheng Lu,Ying Zhang,Peiyao Zhu,Zhiyu Huang

A microemulsion with a CO2 response was prepared by mixing the surfactant sodium oleate (NaOA), the co-surfactant isopropyl alcohol (IPA), oil phase oleic acid (HOA) and water. This surfactant-based microemulsion (SBME) shows a CO2 responsive behavior, and the introduction of CO2 can breakdown the microemulsion. Through the research in this paper, it is found that the content of IPA has a direct impact on the CO2 response behavior of SBME. It was found that the lower the IPA content (22.73 wt%), the more obvious the CO2 response behavior of SBME. Conversely, when the concentration of IPA is high (54.05 wt% and 63.83 wt%), the introduction of CO2 does not directly lead to the demulsification of the microemulsion. NaOA can be converted to HOA under the action of CO2, which is why SBME shows CO2 response behavior. By comparing the effects of CO2 on the (pseudo-)ternary phase diagrams of SBME and surfactant-free microemulsion (SFME), we found evidence that SBME shows different CO2 response behaviors. When CO2 was bubbled into the SBME system with a low IPA content, IPA cannot stabilize the excessive HOA and water in the system and eventually break the microemulsion. The situation is different when CO2 is applied to the SBME system with a high IPA content. IPA as an amphiphilic solvent can stabilize the HOA and water in the system to form SFME. In this process, SBME can be demulsified (low IPA content) or can be converted to SFME (high IPA content) in the presence of CO2.

Safety-reinforced rechargeable Li-CO2 battery based on a composite solid state electrolyte

Wang Rui,Zhang Xuejing,Cai Yichao,Nian Qingshun,Tao Zhanliang,Chen Jun

The rechargeable Li-CO 2 battery has been receiving significant attention owing to its merits of high energy density and the efficient utilization of CO 2 . However, the widely application is plagued by severe security risks, such as leakage, flammability and lithium dendrites growth due to the use of liquid organic electrolytes. Here, a composite solid state electrolyte consisting of polyethylene oxide (PEO) and 20 wt.% Li 7 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) was prepared and first introduced into Li-CO 2 battery to solve the problems. The composite solid state electrolyte exhibited high ionic conductivity (1.03 × 10 −1 S·cm −1 at 70 °C), wide electrochemical window (5 V vs. Li + /Li), good mechanical properties and excellent flexibility. Ultimately, the Li symmetric cell with PEO/LLZTO composite solid state electrolyte can operate 1,500 h at a current density of 0.1 mA·cm −2 . The assembled all-solid-state Li-CO 2 battery behaved a long cycle life of 70 cycles at a current density of 100 mA·g −1 with fixed capacity of 1,000 mAh·g −1 . Our work provides new perspective to develop rechargeable all-solid-state Li-CO 2 batteries.