This figure shows the research route map of the Yang group. We design membrane materials with ideal crystalline structure and chemical composition at atomic/molecular level, and develop strategies to control the growth of crystals and crystal boundaries at the micro/nano level for the synthesis of high-performance membranes. We construct membrane reactors to integrate reaction and separation for process intensification at the centimeter/meter level. Our target is to design high-performance membranes for important separation processes, disclose the science behind membrane and catalysis, develop membrane related technologies and commercialize membrane technologies for new separation and reaction-separation processes in industries.
Mixed Conducting Membranes
Mixed ionic-electronic conducting materials with crystal structures of perovskite (ABO3, top left) and fluorite (MO2, bottom left) can be used as membranes for oxygen or hydrogen separation, electrodes of solid oxide cells for energy conversion. The key of these materials is the oxygen ionic transport in lattice (top middle), across the grain boundaries (bottom middle) as well as oxygen exchange on gas-solid interfaces (center). We develop materials according to requirements of catalytic reactions in membrane reactors (right), and construct permeation models to deep understand the bulk and interface kinetics of the electrochemical processes, as well as the science of reaction-separation coupling in the solid oxide devices.
The Yang group is developing the science and technologies related to mixed ionic-electronic conducting materials as membrane separators, membrane reactors and catalysts for gas purification, process intensification, and cells and batteries. The research activities involve new materials development, design of membrane reactors for new catalytic reaction-separation coupling, conversion of small and stable molecules in catalytic membrane reactors, development of models to disclose the permeation and reaction kinetics in membrane separators and reactors, as well as various techniques related to the practical application of the membrane processes. In recent years, we proposed a new principle for the design of dual-phase oxygen permeable membranes leading to a significant increase of oxygen permeability of dual-phase membranes, built an oxygen permeation model with clear parameter meanings for correct describing the oxygen permeation process. We disclosed the degradation mechanism of membranes at low temperatures and developed simple and widely applicable methods to stabilize the permeation at low temperatures.
Materials development for O2
Preparation methods of ceramic membranes
Transport kinetics of O2
Membrane modules development
Electrochemical oxygen activation for membranes, cells and batteries
-tolerant oxygen-permeable ceramic membranes for hydrogen separation with a performance comparable to those of palladium-based membranes, W. Li, Z. Cao, L. Cai, L. Zhang, X. Zhu, W. Yang, Energy Environ. Sci., 2017, 10, 101-106.
Selection of oxygen permeation models for different mixed ionic-electronic conducting membranes, Y. Zhu, W. Li, Y. Liu, X. Zhu
, W. Yang, AIChEJ.,
2017, 63, 4043–
Nanoparticles at grain boundaries inhibit the phase transformation of perovskite membrane, Y. Liu, X. Zhu, M. Li, R. P. O’Hayre, W. Yang, Nano Lett.
, 2015, 15, 7678-7683.
Stabilization of low-temperature degradation in mixed Ionic and electronic conducting perovskite oxygen permeation membranes, Y. Liu, X. Zhu, M. Li, W. Yang, Angew. Chem. Int. Ed., 2013, 52, 3232-3236.
Permeation model and experimental investigation of mixed conducting membranes, X. Zhu, H. Liu, Y. Cong, W. Yang, AIChE J.
, 2012, 58, 1744-1754.
Molecular Sieving Membranes
In the top and bottom row illustrate architectural design of molecular sieving membranes, including interfacial intensification and mixed-phase integration at mesoscopic level and tailoring aperture size/cage size and orientation as well as post-decoration of functional linkers at microscopic level. In the middle present one frontier of molecular sieving membranes, namely, 2D ultrathin membranes.
Zeolites and metal-organic frameworks (MOFs) are important molecular sieves, giving rise to permanent and regular porous networks. The Yang Group has been devoting to synthesis and application of zeolite and MOF membranes with superior selectivity, permeability and stability, seeking for an alternative energy-efficient and environment-friendly separation solution towards organics refinery, CO2 capture, H2 purification, CH4 upgrading, paraffine/olefin extraction, etc. We explore an optimal set of synthesis methodology to controllably manipulate the microstructure of molecular sieving membranes to intensify the boundary structures and eliminate interfacial defects. We also dedicate to develop mixed-phase composite membranes, taking advantage of the synergistic sieving effect of mixed phase by rational assembly and integration. Simultaneously, architecture design and manipulation of molecular sieving membranes at microscopic level has been made to further improve membranes, including tailoring aperture size/cage size and channel orientation as well as post decoration of functional linkers. In recent years, the pioneering works on 2D ultrathin MOF membranes have been carried out in the Yang Group. 2D ultrathin MOF membranes are attractive, enabling minimization of the transport resistance and maximization of the permeability. In future, we will make much attempt to develop 2D ultrathin MOF and MOF-beyond membranes with precise molecule discrimination.
Pure molecular sieving membranes
Mixed matrix membranes
Microstructure design and tailoring of molecular sieving membranes
Nanosheets-based ultrathin molecular sieving membranes
Novel molecular sieving membranes
Microstructural engineering and architectural design of metal-organic framework membranes, Y. Liu, Y. J. Ban, W. S. Yang, Adv. Mater., 2017, 29, 1606949.
Two-dimensional metal-organic framework nanosheets for membrane-based gas separation, Y. Peng, Y. S. Li, Y. J. Ban, W. S. Yang, Angew. Chem. Int. Ed., 2017, 33, 9757–9761.
Confinementof ionic liquids in nanocages: Tailoring the molecular sieving properties of ZIF-8 for membrane-based CO2
capture, Y. J. Ban, Z. J. Li, Y. S. Li,Y. Peng, H. Jin, W. M. Jiao, A. Guo, P. Wang, Q. Y. Yang, C. L. Zhong, W. S.Yang, Angew. Chem. Int. Ed.
, 2015, 54, 15483–15487.
Metal-organic framework nanosheets as building blocks for molecular sieving membranes, Y. Peng, Y. S. Li, Y. J. Ban, H. Jin, W. M. Jiao, X. L. Liu, W. S. Yang, Science, 2014, 346, 1356–1359.
An organophilic pervaporation membrane derived from metal–organic framework nanoparticles for efficient recovery of bio-Alcohols, X. L. Liu, Y. S. Li, G. Q. Zhu, Y. J. Ban, L. Y. Xu, W. S. Yang, Angew. Chem. Int. Ed., 2011, 50, 10636–10639.
Reaction and separation can be integrated in a membrane reactor with great energy saving and process simplification. In the membrane reactor, one of the products can be in-situ selectively removed or input through membranes, which can promote the generation of target products as well as eliminate undesired side reactions. The research activities in our research group involve application-oriented design of membrane materials, establishment of membrane reactors and development of models to comprehend the synergetic functions of reaction and separation. Recently, we proposed a new catalytic membrane reactor to fulfill a nine-step industrial process in one-step, and proposed a new concept for the highly efficient hydrogen separation using oxygen permeable membranes. Now, new membrane reactors are to be developed for the conversion of small and stable molecules or biomass-derived platform chemicals to value-added chemicals and fuels.
Oxygen permeable membrane reactors
MOF and MOF-based composite membrane reactors
Zeolite membrane reactors
Electrochemical catalytic membrane reactors
Kinetics of reaction-separation coupling
S-tolerant oxygen-permeable ceramic membranes for hydrogen separation with a performance comparable to those of palladium-based membranes, W. Li, Z. Cao, L. Cai, L. Zhang, X. Zhu, W. Yang, Energy Environ. Sci., 2017, 10, 101-106.
High-rate hydrogen separation using an MIEC oxygen permeable membrane reactor, W. Li, Z. Cao,X. Zhu, W. Yang, AIChE J., 2017, 63, 1278-1286.
Integration of nine steps for producing ammonia and liquid-fuel synthesis gases in one membrane reactor, W. Li, X. Zhu, S. Chen, W. Yang, Angew. Chem. Int. Ed., 2016, 55, 8566-8570.
Conversion of xylose into furfural in a MOF-based mixed matrix membrane reactor, H. Jin, X. L. Liu, Y. J. Ban, Y. Peng, W. M. Jiao, P. Wang, A. Guo, Y. S. Li, W. S. Yang, Chem. Eng. J., 2016, 305, 12–18.
Improving oxygen permeation of MIEC membrane reactor by enhancing the electronic conductivity under intermediate-low oxygen partial pressures, L. Cai, W. Li, Z. Cao, X. Zhu, W. Yang, J. Membr. Sci., 2016, 520, 607-615.
Zeolite Membrane Commercialization
Zeolites are microporous aluminosilicates composed of tetrahedra linked together at the corners to form a highly regular three-dimensional network. Zeolites are ideal membrane materials due to their extraordinary thermal, mechanical and chemical stability. Zeolite membranes have been extensively studied ever since 1989. It has been demonstrated that the separation performance of zeolite membranes was influenced by not only their framework topologies, but also multiple microstructural factors such as membrane thickness, Si/Al ratio, preferred orientation and grain boundary. Several methods and techniques (like microwave heating) have been developed and proven quite effective for a more precise control over their microstructures.
The Yang group are one of the first research groups exploring microwave heating synthesis of zeolite membranes. Taking NaA zeolite membrane as an example, its preparation involved dip-coating of microwave-synthesized NaA seeds or ex situ seeding on the substrate followed by microwave heating secondary growth (Left). In view of this, a novel“in situ aging-microwave heating” method was developed for the synthesis of NaA membrane. The concept could be further extended to other types of zeolite membranes, i.e., FAU-type, T-type. Of particular note, microwave-assisted technique has been successfully used for large-scale production of LTA membranes (Top right), and the microwave-synthesized zeolite membrane unit can be used for dewatering of organics through pervaporation or vapor permeation (Bottom right).
Microwave synthesis of zeolite membranes (LTA, FAU, T…)
Dewatering of organics (alcohols, Ethers, Ketones, Esters…) through pervaporation or vapor permeation
Scaling up synthesis and application processes of zeolite membranes
Suppression of twins in b-oriented MFI molecular sieve films under microwave irradiation, Y. Liu, Y. Li, R. Cai, W. Yang, Chem. Commun., 2012, 48
Fabrication of highly b-Oriented MFI film with molecular sieving properties by controlled in-plane secondary growth, Y. Liu, Y. Li, W. Yang, J. Am. Chem. Soc., 2010, 132, 768.
Microwave synthesis of high performance FAU-type zeolite membranes: Optimization, characterization and pervaporation dehydration of alcohols, G.Zhu, Y. Li, H. Zhou, J. Liu, W. Yang, J. Membr. Sci., 2009, 337, 47-54.
Microwave synthesis of zeolite membranes: A review, Y. Li, W. Yang, J. Membr. Sci.,
2008, 316, 3-17.
Synthesis of a high-permeance NaA zeolite membrane by microwave heating, X. Xu, J. Liu, W. Yang, L. Lin, Adv. Mater., 2000, 12, 195-198.
The left picture illustrates the structure of Mo-V-based mixed metal oxides with hexagonal and heptagonal channels, which are formed by the building unit assembly of polyoxomolybdates under hydrothermal conditions. And the particular channel structure can adsorb and activate small molecules (such as ethane and propane), and transform them into high-value chemicals. Of particular note, large-scale production of Mo-V-based mixed metal oxides has been successfully developed by hydrothermal technique (Top right), and the ring-shaped catalysts have been successfully used for pilot test of propane oxidation to acrylic acid (Bottom right).
The fossil feedstock in recent years is shifting towards light alkanes (C2~C4) due to the abundant resources, lower prices and negligible environment impact. The conversion of light feedstocks to high-value chemicals (polymers, paints, lubricants etc.) through highly-selective catalysts in the presence of oxygen is an increasing important topic. At present, the most promising catalysts are mixed metal oxides，VPO catalyst and heteropoly compounds due to their outstanding performance under favorable reaction conditions. MoVTeNbO mixed metal oxide with excellent activity and selectivity has been successfully developed in our group for propane oxidation to acrylic acid. The large-scale synthesis of catalysts and demonstration plant for 1000 t/a production of acrylic acid are in progress. New catalytic materials are also being investigated for their properties and applications in selective oxidation of light alkane.
Oxidative dehydrogenation of light alkanes
Selective (amm) oxidation of light alkanes
Oxidative removal of CO in effluent from the selective oxidation of light alkanes
Preparation of MoVTeNbO catalyst and its catalytic application for oxidation of ethane to ethylene, W. Yang, H. Wang, W. Chu, China patent, ZL 201410198867.2.
A new technique for continuous production of acrylic acid by oxidation of propane, W. Yang, W. Chu, H. Wang, Z. Hu, China patent, ZL 2014 10172716.X.
Preparation of Mo-V-Te-Nb-O catalyst and its application, W. Yang, Z. Deng, W. Chu, H. Wang, China patent, ZL 2008 10012030.9.
Preparation of MoVTeNbO catalyst for selective oxidation of propane to acrylic acid, W. Yang, B. Zhu, H. Li, H. Wang, Z. Deng, China patent,
ZL 2004 10100456.1.
The procedure and method for selective oxidation of propane to acrylic acid, W. Yang, W. Chu, H. Wang, Y. Liu, X. Li, Q. Li, H. Wang, China patent, 201510593298.6.