DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 9
·2887-2897
·
IF 4
Zhifeng He,Xin Cui,Guangping Lei,Zeyi Liu,Xiaoyang Yang,Yifu Liu,Jiafeng Wan,Fangwei Ma
Molybdenum (Mo) is one of the most important constituent elements in natural nitrogenase and theoretical calculation results show that Mo-based materials can be used as potential NRR electrocatalysts. The design of advanced catalysts with a special structure is very essential for promoting the development of electrocatalytic N2 into NH3. In this paper, Fe-doped MoO2/C heterostructured nanoparticles with rich oxygen vacancies (Vo) are designed and they exhibit highly efficient catalytic activity for artificial N2 fixation in neutral electrolytes under ambient conditions. The influence of the atomic ratio of the Fe source to the Mo source and the NaBH4 ethanol solution treatment on the structure and electrocatalytic performance are systematically investigated. The Vo-Fe–MoO2/C (1 : 50) catalyst with rich oxygen vacancies shows a satisfactory electrocatalytic N2 reduction reaction (e-NRR) activity in 0.1 M Na2SO4 with a high ammonia yield rate of 15.87 ± 0.3 μg h−1 mg−1 at −0.5 V versus the reversible hydrogen electrode (vs. the RHE) and a FE of 13.4% at −0.3 V (vs. the RHE). According to the results of DFT calculations, the active center of the electro-catalytic nitrogen reduction reaction is the molybdenum atom between the iron atom and the O vacancy. Oxygen vacancies can not only reduce the energy barrier of the RDS but also facilitate the desorption of ammonia and the first step hydrogenation of nitrogen. The doping of Fe will change the electronic state of the Mo atom in MoO2.
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JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Run Li,Ying Yang,Zezhou Zhang,Shaohan Lian,Quan Zhao,Chunfeng Song
As a promising strategy to reduce greenhouse gas emissions, carbon dioxide capture from industrial and power plants has been proposed. Due to its advantages of low consumption and a modest environmental impact, membrane technology has been widely used in the gas separation process. Advanced porous fillers can be successfully added into the polymer matrix to create mixed matrix membranes (MMMs) with simple processing and applicable gas separation performance. The high porosity and stability of microporous carbon materials make them desirable for use in the gas separation process. Herein, N-doped microporous carbon microparticles (NMCP) were successfully synthesized and incorporated into UV crosslinked polyethylene oxide (XLPEO) matrix membranes. Fast CO 2 transport channels are created in MMMs by rationally constructing NMCP fillers with ultra-micropores (∼0.53 nm), high-content heteroatoms (N, 13.94%), and two-dimensional morphology. The relationship between the structure of the NMCP samples and the gas separation performance of MMMs was discussed. Additionally, tests were conducted on the effects of NMCP loading, operating conditions, and long-term stability of NMCP/XLPEO membranes. NMCP/XLPEO membranes with a 2.5 wt% NMCP loading displayed a CO 2 permeability of 606 Barrer and a CO 2 /N 2 selectivity of 56.4, approaching the 2019 upper bound. This work offers a novel perspective to build fast gas transport channels in porous carbon-based MMMs for carbon capture.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Jing Yu,Shihao Xiong,Bichen Wang,Rui Wang,Beibei He,Jun Jin,Huanwen Wang,Yansheng Gong
Rational design of cheap and easily available semiconductor photocatalysts for photocatalytic nitrogen fixation has attracted widespread attention. However, the enhancing efficiency of fixation nitrogen into ammonia (NH 3 ) under mild conditions is still a challenge. Based on the energy band engineering theory, the band gap of graphitic carbon nitride (g-C 3 N 4 ) can be adjusted by boron element doping. In this study, boron-doped graphitic carbon nitride with a porous rod-like 2D/1D hierarchical architecture was prepared (BCN) via a convenient hydrothermal and thermal polymerization method. Due to its special structure, the as-prepared BCN photocatalysts had a high specific surface area, enhanced visible light absorption and good photogenerated carrier separation efficiency. The optimal ammonia yield of BCN can reach 434.74 μmol·g −1 ·h −1 without the presence of a sacrificial agent, which was 57.35 times higher than that of bulk g-C 3 N 4 . According to the analysis of the experimental results, the excellent photocatalytic nitrogen fixation performance was due to the synergistic effect between the doping of nonmetallic boron element and the 2D/1D porous structure, which exposed more active sites, thus boosting the photocatalytic nitrogen fixation efficiency. This study provides a guiding significance for the construction of high-efficiency photocatalysts with a special 2D/1D porous hierarchical architecture in photocatalytic nitrogen fixation.
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JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Qingping Xin,Xinghui Zhang,Wei Shao,Hong Li,Yuzhong Zhang
The purification of sulfur dioxide (SO 2 ) from the flue gas is an urgent problem given its toxicity to humans and organisms and attendant environmental concerns. In this study, aiming at the separation of SO 2 , mixed matrix membranes (MMMs) are fabricated by incorporating covalent organic framework (COF) into Pebax 1657 polymer matrix . By strengthening the solubility-diffusion mechanism of SO 2 gas molecules, SO 2 /N 2 gas separation performance is investigated. Firstly, MMMs are fabricated by incorporating a porous framework material (TpPa-1) containing SO 2 affinity groups into the Pebax 1657 matrix as a filler. Then the azo group (Azo) is introduced into the MMMs by the method of physical blending. The MMMs with light-responsive characteristic are fabricated by introducing TpPa-1 blended with pAAB into the Pebax 1657 polymer matrix. Secondly, the SO 2 /N 2 separation performance of Pebax/TpPa-1 MMMs is improved with the increasing of filler loading. Specially, the Pebax/TpPa-1 membrane with 5 wt% exhibits the most excellent SO 2 /N 2 separation performance with SO 2 permeability of 1709 Barrer and SO 2 /N 2 selectivity of 811. The MMMs overcome the trade-off effect and achieve enhancement of SO 2 permeability and SO 2 /N 2 selectivity simultaneously. Thirdly, both the SO 2 permeabilities and SO 2 /N 2 selectivities of Pebax/pAAB@TpPa-1-5% membrane exhibit regular and reversible changes under UV–Vis light-conversion conditions, indicating that MMMs containing Azo possesses dynamic light-responsive properties. Furthermore, TpPa-1 and pAAB repel each other in the membrane because both have negative charges, resulting in the forced surface segregation of COF in the Pebax/pAAB@TpPa-1 MMMs.
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RENEWABLE ENERGY
·
2022
·
IF 8.634
Zhuoheng Tu,Ping Zhang,Mingzhen Shi,Xiaomin Zhang,Youting Wu,Xingbang Hu
Efficient recovery of CO and H 2 from offgas streams is environmentally and economically meaningful from the view point of the wide use of syngas (CO/H 2 ) in the chemical industry. This work reports selective and simultaneous separation of CO and H 2 from N 2 using protic chlorocuprate ionic liquids (PCILs)-based membranes. The chemical structures of the prepared PCILs were characterized using FTIR , NMR and ESI-MS, and the thermal stability, melting points, viscosity and density of PCILs were determined. The morphology and elemental distribution of PCIL-based membranes were characterized by SEM and EDS. Facilitated transport of CO is observed in these membranes, and the CO permeability is up to 178.3 barrers (0.1 bar, 40 °C) in [TEAH][CuCl 2 ], with a CO/N 2 selectivity of 26.2. H 2 permeability and H 2 /N 2 selectivity are also found to reach 198.2 barrers (0.5 bar, 40 °C) and 29.1, respectively. The permeability of CO and the selectivity of CO/N 2 can be further optimized to 405.9 barrers and 69.9 by altering the Cu(I) content, respectively. In addition, the selectivity of CO/H 2 can be tuned drastically via varying the Cu(I) content (from 0.77 to 12.0) and the operating temperature (from 2.14 to 0.42), which may be applied to the composition adjustment of syngas. In a word, this work offers a new strategy for designing IL-based membranes that used for CO and H 2 capture.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Rui Ding,Ziheng Li,Yan Dai,Xiangcun Li,Xuehua Ruan,Jiaming Gao,Wenji Zheng,Gaohong He
The amino functionalization of MOFs has been verified to be effective in improving the selective permeation of CO 2 . However, the introduction of amino groups into ZIF-8 by mixed ligands strategy is hard to achieve due to the high steric hindrance of benzene ring in 2-aminobenzimidazole ligand, resulting in insufficient content of amino groups. Therefore, in this work, polystyrene-acrylate (PSA) template is proposed to provide abundant adsorption and reaction sites for the rapid synthesis of NH 2 -ZIF-8 with high content of 2-aminobenzimidazole. Furthermore, the incomplete etching strategy is used to construct PSA modified hollow NH 2 -ZIF-8 nanospheres (PHNZ). Importantly, the thickness of PSA layer and the hollow size are adjusted by the etching time, as revealed by the SEM and TEM images. In this PHNZ, the modified PSA can provide good interface compatibility between PHNZ and Pebax matrix to enhance the CO 2 selectivity, while the hollow structure can reduce the mass transfer resistance and improve the gas permeability. Moreover, the introduced amino groups can enhance the CO 2 affinity of PHNZ and further improve the CO 2 /N 2 selectivity of the PHNZ-based mixed matrix membranes (MMMs). Benefiting from the synergy of good interface compatibility and enhanced CO 2 affinity from the amino groups, the PHNZ/Pebax MMMs present greatly improved CO 2 /N 2 selectivity in contrast with pure Pebax and NH 2 -ZIF-8 based membranes. Besides, as the etching time increases, the PHNZ-2 and PHNZ-3 based MMMs present a higher CO 2 permeability than that of NH 2 -ZIF-8 based MMM, revealing the significance of the hollow structure. The PHNZ-2/Pebax MMM with filler loading of 10 wt% expresses the best gas separation performance with the CO 2 permeability of 121.9 Barrer and CO 2 /N 2 selectivity of 96.6, respectively, showing an increase of 54.7 % and 98.0 % in contrast with pure Pebax membrane. Meanwhile, this CO 2 separation performance is far beyond the Robeson upper bound in 2008 and close to the McKeown upper bound in 2019, demonstrating that the proposed PHNZ displays a promising and competitive potential in MMM based CO 2 capture.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 11
·116518
·
IF 4.316
Peipei Li,Dan Cheng,Xiaohua Zhu,Meiling Liu,Youyu Zhang
Compared with the traditional Haber-Bosch process, electrochemical N2 to NH3 reduction affords an eco-friendly and sustainable alternative to ambient NH3 synthesis with the aid of efficient electrocatalysts. In this work, partial oxidation of MnS to obtain the MnS-Mn3O4 is proved as a promising noble-free electrocatalysts of N2 to NH3 fixation at ambient conditions. When tested in 0.1 M Na2SO4, the electrochemical N2 reduction reaction performance of MnS-Mn3O4 is improved comparing with the MnS, which achieves large NH3 yield of 16.74 μg h–1 mgcat.–1 and a high Faradaic efficiency of 5.72%. It also exhibits excellent selectivity of N2 to NH3 and strong long-term electrochemical stability.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Chunran Zhao,Lin Yue,Shude Yuan,Xujie Ren,Zhihao Zeng,Xin Hu,Leihong Zhao,Ying Wu,Yiming He
A composite of cheap metallic Bi-decorated ZnSnO 3 was synthesized via a solvothermal method and applied for photocatalytic N 2 fixation for the first time. The results demonstrated that the Bi/ZnSnO 3 composite with 1.5 % Bi exhibited superior photocatalytic performance. with the optimal sample producing NH 3 at a rate of 988 μmol/L g -1 h −1 under simulated sunlight. This is 5 times faster than that of pure ZnSnO 3 . Additionally, the Bi/ZnSnO 3 composite showed significantly better photocatalytic performance than pure ZnSnO 3 in RhB degradation. Structural analyses confirmed successful loading of Bi nanoparticles on the surface of ZnSnO 3 . Furthermore, diffuse reflectance spectroscopy analysis revealed that the surface plasmon resonance effect of metal Bi effectively improved the optical absorption performance. However, the sensitization of metal Bi had a limited contribution to the high photocatalytic activity of the Bi/ZnSnO 3 . Electrochemical analyses indicated that the Schottky barrier formed between Bi and ZnSnO 3 captured photo-generated electrons and promoted the charge separation, which was considered responsible for the increased photoactivity of Bi/ZnSnO 3 .This work provides a new application of Bi/ZnSnO 3 and may offer new ideas for the application of ZnSnO 3 materials in the field of photocatalysis, which are crucial for addressing environmental pollution and energy conversion challenges.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Congli Li,Jiang Wang,Zhenfei Wang,Jinxiang Dong,Qi Shi
CuCl/NaY is the most representative π-complexation adsorbent, prepared by solid thermal dispersion followed by vacuum thermal activation. However, determining the autoreduction behavior of Cu species for CuCl/NaY adsorbent in vacuum thermal activation has rarely been researched. This study characterized the valence state, location, and types of Cu species during thermal dispersion and vacuum activation. During the thermal dispersion, Cu species were uniformly dispersed into NaY micropores. Under vacuum activation at 100 °C, the location of Cu species changed, migrating from supercages to near the plane (toward the sod cage or the supercage side) of the 6-membered ring connecting the supercage and sod cage. However, by activating at 150 °C, vacuum autoreduction occurred: (Cu 2+ –O − )Cl − species evolved into Cu + Cl − species. This was accompanied by the migration of Cu(I) species to the appropriate CO adsorption site on the plane center of the six-membered ring connecting the supercage and sod cage in the NaY framework, which achieved confined dispersion. The CO adsorption capacity of CuCl/NaY activated at 150 °C was 2.75 mmol/g, significantly higher than when activated at 100 °C. When activated at 200 °C, Cu(II) species was further reduced to Cu(I) slightly, which had not migrated to an effective adsorption site. Our results show the Cu species’ evolution and autoreduction behavior for CuCl/NaY adsorbent under vacuum thermal activation, and they can serve as a reference to guide the preparation of π-complex adsorbents.
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Small
·
2023
·
IF 13.3
Heng Guo,Peng Yang,Yuantao Yang,Haoran Wu,Fengying Zhang,Zhen-Feng Huang,Guidong Yang,Ying Zhou
Ambient electrocatalytic nitrogen (N 2 ) reduction has gained significant recognition as a potential substitute for producing ammonia (NH 3 ). However, N 2 adsorption and *NN protonation for N 2 activation reaction with the competing hydrogen evolution reaction remain a daunting challenge. Herein, a defect-rich TiO 2 nanosheet electrocatalyst with PdCu alloy nanoparticles (PdCu/TiO 2−x ) is designed to elucidate the reactivity and selectivity trends of N 2 cleavage path for N 2 -to-NH 3 catalytic conversion. The introduction of oxygen vacancy (OV) not only acts as active sites but also effectively promotes the electron transfer from Pd-Cu sites to high-concentration Ti 3+ sites, and thus lends to the N 2 activation via electron donation of PdCu. OVs-mediated control effectively lowers the reaction barrier of *N 2 H and *H adsorption and facilitates the first hydrogenation process of N 2 activation. Consequently, PdCu/TiO 2−x catalyst attains a high rate of NH 3 evolution, reaching 5.0 mmol g cat. −1 h −1 . This work paves a pathway of defect-engineering metal-supported electrocatalysts for high-efficient ammonia electrosynthesis.
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JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 31
·15252-15262
·
IF 3.553
Jiang Xiaoli,He Miao,Tang Mengyi,Zheng Qiaoji,Xu Chenggang,Lin Dunmin
Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions has been considered as a promising approach for green ammonia synthesis; however, non-precious metal-based catalysts with excellent NRR electrocatalytic performance have been scarce. Herein, self-supported bimetallic electrocatalysts of Ni 12 P 5 /FeP 4 nanoplates grown on carbon cloth were synthesized by a combined process of hydrothermal technology and low-temperature phosphidation. The catalyst exhibits excellent electrocatalytic N 2 fixation performance with a high NH 3 yield rate of 3.08 × 10 −10 mol s −1 cm −2 (16.40 μg h −1 mg −1 cat
), Faradaic efficiency (39.9%) as well good durability at − 0.1 V in 0.1 M Na 2 SO 4 at ambient conditions, which are attributed to the distinctive nanostructure and rational composition. Our study paves the way for expanding the scope of NRR research and designing more efficient electrochemical ammonia synthesis in the future.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Shanyin Dai,Ruoxing Liao,Haoli Zhou,Wanqin Jin
In this study, triptycene-based carboxylic acid (triptycene-2,3,6,7-tetracarboxylic acid) was synthesized for polycondensation with two amino compounds to ultimately form linear polyamides with different backbone structures. Characterizations, including nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy, were performed to confirm the polycondensation, and the structural properties were determined. Solubility of the synthesized polyamides was also measured. Subsequently, these polyamides were fabricated into membranes to investigate the separation of N 2 over the VOCs, and their stability and separation performance under different operating conditions were determined. Good separation performance, such as a rejection rate above 95%, was obtained during the studied separation range for the N 2 /VOC mixture, indicating that a linear polymer can also be used for the separation of a condensable gas/vapor mixture and only the rotation of polymer chains can be restricted to a certain extent by the side groups.
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