Membrane separation technology offers great potential due to its low energy consumption and continuous operation availability. Metal-organic frameworks (MOFs) are promising in separation membranes due to their abundant species, high porosity, and precise regulation of pore architectures.
　　However, the development process of high-performance MOF membranes is time-consuming and costly, and the membrane is plagued by unavoidable problems such as heterogeneous nucleation, defects, cracks, etc., resulting in the actual separation performance of MOF membranes being far lower than the theoretical simulation value, and not accurately demonstrating the separation ability of the material intrinsic pore structure.
　　The MOF membrane amount to date is only a drop in the bucket compared to the material collections. The fabrication of an arbitrary MOF membrane exhibiting inherent separation capacity of the material remains a challenge.
　　Recently, a research group led by Prof. YANG Weishen and Assoc. Prof. PENG Yuan from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new strategy of modular customization and non-destructive regulation of MOFs for efficient membrane separations.
　　They have achieved rapid regulation of the MOF module and verified the corresponding membrane for highly accurate separation applications, which provided a solid scientific and technical foundation for the research and development of separation membranes to meet the high-efficiency separation requirements of today's bulk/specific industrial products.
　　This work was published in Angewandte Chemie International Edition on Oct. 16.
　　Diagrammatic illustrations of the MOF modular customization concept (Image by SHU lun and PENG yuan)
　　The researchers proposed a strategy to modularize custom defect-free MOF separation membranes. The membrane structure consisted of two parallel modules. One was a discrete MOF module based on the characteristics of heterogeneous mutually reinforcing nuclei, which led to the implementation of molecular mass transfer and separation by exploiting the intrinsic pore structure. The other was the highly cross-linked, ultra-low permeability polyamide module formed by the confined interface polymerization operation, which was responsible for the comprehensive blockade of defects between MOF modules.
　　Guided by this strategy, the MOF module could be randomly replaced to customize the corresponding MOF separation membrane, and high-performance MOF separation membranes could be rapidly produced. With the modified post-synthesis strategy, the MOF module skeleton in the membrane was controlled without loss and the separation accuracy was doubled.
　　The researchers selected four MOFs with different pore/channel sizes and functionalities for batch fabrication of defect-free MOF membranes. Each membrane fully displayed the separation potential according to the MOF pore size.
　　Among them, the NH2-Zn2Bim4 membrane exhibited a high H2/CO2 mixture separation factor of 1656 and H2 permeability of 964 gas permeation unit. Taking advantage of this strategy, the membrane performance could be further enhanced via application-oriented post-synthetic ligand exchange. The H2/CO2 selectivity of the regulated membrane was approximately 200% higher than that of the original membrane.
　　"This strategy provides a tractable route to customize a myriad of high-performance membranes to meet different separation requirements," said Prof. YANG.
　　This work was supported by the National Natural Science Foundation of China.

　　Classical strong metal-support interaction (SMSI) describes that reducible oxide migrates to the surface metal nanoparticles (NPs) to obtain metal@oxide encapsulation structure during high-temperature H2 thermal treatment, resulting in high selectivity and stability.
　　However, the encapsulation structure inhibited the adsorption and dissociation of reactant molecular over metal leading to low activity, especially for the hydrogenation reaction.
　　Recently, a research group led by Prof. LIU Yuefeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new migration strategy, in which the TiO2 selectively migrated to second oxide support rather than the surface of metal NPs in Ru/(TiOx)MnO catalysts, boosting the CO2 reduction to CO via reverse water-gas shift reaction.
　　This study was published in Nature Catalysis on Oct. 9.
　　In-situ generation of highly efficient H-transport channel for CO2 reduction to CO（Image by Hui Kang）
　　The researchers achieved a controlled migration by utilizing the strong interaction between TiO2 and MnO in Ru/(TiOx)MnO catalysts during H2 thermal treatment, and TiO2 spontaneously re-dispersed on the MnO surface, avoiding the formation of TiOx shell on Ru NPs for the ternary catalyst (Ru/TiOx/MnO).
　　Meanwhile, high-density TiOx/MnO interfaces generated during the process, acting as a highly efficient H transportation channel with low barrier, and resulting in enhanced H-spillover for the migration of activated H species from metal Ru to support for consequent reaction.
　　The Ru/TiOx/MnO catalyst showed 3.3-fold catalytic activity for CO2 reduction to CO compared with Ru/MnO catalyst. In addition, the Ti/Mn support preparation was not sensitive to the crystalline structure and grain size of TiO2 NPs. Even the mechanical mixing of Ru/TiO2 and Ru/MnOx enhanced the activity.
　　Moreover, they verified that the synergistic effect of TiO2 and MnO didn't alter the catalytic intrinsic performance, and efficient H transport provided a large number of active sites (hydroxyl groups) for the reaction process.
　　"Our study provides references for the design of novel selective hydrogenation catalysts via the in-situ creation of oxide-oxide interfaces acting as hydrogen species transport channels," said Prof. LIU.
　　This work was supported by the NSFC of China, the Liaoning Revitalization Talents Program, the Dalian National Laboratory for Clean Energy and the AI S&T Program of Yulin Branch, the Dalian National Laboratory for Clean Energy of CAS.

Alkaline CO2 electrolysis can produce multicarbon (C2+) products such as ethylene and acetate, yet suffers from low CO2 utilization efficiency.Ttandem electrolysis, which connects solid oxide or acidic CO2 electrolysis to CO and alkaline CO electrolysis to C2+ products in sequential electrolyzers, is a carbon-efficient route. However, to date, CO electrolysis generally shows high current density and selectivity for C2+ products, but selective generation of a specific C2+ product is still challenging.Recently, a research team led by Profs. WANG Guoxiong and GAO Dunfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new strategy by constructing metal-organic interfaces for CO electrolysis to acetate with high selectivity.This study was published in Angewandte Chemie International Edition on Sep. 25.Boosting CO electrolysis to acetate with Cu-organic interface (Image by RONG Youwen)The researchers tuned the reaction microenvironments surrounding catalytically active sites by constructing Cu-organic interfaces through in-situ electrochemical reconstruction of molecular Cu complexes. Benefiting from the favorable reaction microenvironment, they achieved good catalytic performance for CO electrolysis to acetate, in terms of current density, Faradaic efficiency, and yield.With a copper phthalocyanine (CuPc) electrode measured in a home-made alkaline membrane electrode assembly (MEA) electrolyzer, they obtained an acetate Faradaic efficiency as high as 84.2% and an acetate carbon selectivity of 92.1% at 500 mA cm-2. The maximum acetate partial current density and formation rate reached 605 mA cm-2 and 0.38 mmol min-1, respectively, translating into an acetate yield as high as 63.4%.The Cu-organic interface created a favorable reaction microenvironment that enhanced *CO adsorption, lowered the energy barrier for C-C coupling, and facilitated the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production."Our study highlights the potential of constructing metal-organic interfaces for tailoring reaction microenvironments for highly selective production of a specific C2+ product from CO electrolysis," said Prof. GAO.The above work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Collaborative Innovation Center of Chemistry for Energy Materials, and the Youth Innovation Fund of DICP.

　　Acetylene hydrogenation to ethylene (AHE) in combination with acetylene production from coal pyrolysis is considered as a promising alternative to the traditional petroleum-based ethylene production route. However, thermocatalytic AHE (T-AHE) process often suffers from high temperatures (100-300 oC) and high consumption of molecular hydrogen (H2).
　　Recently, a research group led by Prof. DENG Dehui and Assoc. Prof. YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) realized a new process of acetylene hydrogenation to ethylene by directly using water as hydrogen source (WAHE) and low-cost CO as oxygen acceptor over a Au/α-MoC catalyst.
　　This study was published in Nature Catalysis on September 28.
　　Acetylene hydrogenation to ethylene by water at low temperature on a Au/α-MoC catalyst (Image by HUANG Rui)
　　The hydrogenation of acetylene can proceed by a H2-based thermocatalytic route or H2O-based electrocatalytic route. The thermocatalytic AHE is energy
　　demanding due to the requirement of relatively high temperature and H2 consumption, since H2 is also industrially produced by energy-intensive processes such as steam methane reforming (SMR) and water gas shift (WGS) reaction.
　　The electrochemical AHE (E-AHE) process is advantageous as it directly uses electrochemically-generated active hydrogen species from water to hydrogenate acetylene without involving the unnecessary formation of H2. 
　　The WAHE process delivered over 99% acetylene conversion and high ethylene selectivity of 83% at 80 oC.
　　Mechanistic studies revealed that in-situ generated hydroxyl species from water dissociation at the boundary of Au and α-MoC, serving as mild reductants, enabled the selective semi-hydrogenation reaction with residual O removed by CO. This process circumvents H2 consumption in the classical route and opens avenues for energy-efficient acetylene hydrogenation by water at low temperature.
　　This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China and the Strategic Priority Research Program of CAS.

　　A research group led by Prof. DENG Dehui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has realized direct conversion of air to nitric acid (HNO3) under ambient conditions through a hydroxyl radical (·OH)-mediated hetero-homogeneous electro-chemical route.
　　In the route, the N2 was oxidized to HNO3 by employing heterogeneous electroreduction of O2 to H2O2 on a graphite rod catalyst combined with homogeneous Fe2+-induced dissociation of the in situ generated H2O2 to OH· as reactive oxidation species.
　　The study was published in Nature Synthesis on September 25.
　　HNO3, as an important chemical building block, is produced industrially from the oxidation of ammonia via the Ostwald process, which requires high temperatures above 800 oC. In this process, the feed ammonia gas is industrially synthesized via the energy-intensive Haber-Bosch method typically operating at high temperatures (400 to 500 oC) and pressures (20 to 50 MPa).
　　Direct conversion of dinitrogen (N2) and oxygen (O2) in the air to HNO3 under mild conditions is a promising and sustainable route for the production of HNO3. However, the thermodynamic and kinetic restrictions of this reaction as well as the high stability of N2 and the low activity of O2, make it a challenge to achieve co-activation and efficient conversion of the two molecules in the air toward HNO3 synthesis.
　　Schematic illustration for the hetero-homogeneous electrochemical conversion of air to HNO3 (Image by CHEN Shiming and YU Liang)
　　In this study, the researchers developed a hetero-homogeneous electro-chemical route for the direct conversion of air to HNO3 at the cathode compartment. At the cathodic potential of 0 V vs. RHE, the faradaic efficiency of nitric acid was as high as 25.37%, and the selectivity was over 99%, which was superior than the previously reported electrocatalytic oxidation of N2 at the anode with high potentials above 1.23 V vs. RHE.
　　Multiple in situ spectroscopic characterizations and theoretical calculations revealed that ·OH produced from Fe2+-induced dissociation of in-situ generated H2O2 could efficiently activate N2. This delivered a high HNO3 productivity of 141.83 μmol·h-1·gFe-1 which was 225 times that of directly using H2O2 as the oxidant.
　　"This process for HNO3 synthesis from N2 and O2 effectively avoids the traditional high-temperature and high-pressure reaction conditions, and provides a new route for the co-activation and efficient conversion of N2 and O2 under mild conditions," said Prof. DENG.
　　The above work was supported by the National Natural Science Foundation of China, the National Key R&D Program of China, and the Strategic Priority Research Program of CAS.

Direct conversion of methane (CH4) to high value-added chemicals at room temperature, by directly using abundant and low-cost molecular oxygen (O2) as an oxidant, is an ideal route for CH4 utilization. But it remains a challenge owing to the chemical inertness of methane and low activity of O2.Recently, a research group led by Prof. DENG Dehui and Assoc. Prof. YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) realized direct CH4 conversion to C1 oxygenates (CH3OH, HOCH2OH and HCOOH) with O2 at room temperature (25 oC) over an edge-rich MoS2 catalyst.This study was published in Nature Catalysis on September 21.Room-temperature CH4 conversion by O2 over bi-Mo sites confined in MoS2 edge (Image by MAO Jun and LIU Huan)Catalytic conversion of methane to high value-added chemicals is a tough problem due to the low polarization rate and high C-H bond energy (439 kJ mol-1) of methane.Typical catalytic conversion of CH4 usually operates at high temperatures (over 600 oC), or in the aid of strong oxidants (such as fuming sulfuric acid) or external fields (such as plasma). Nevertheless, such harsh reaction easily leads to excessive conversion of the target product, such as overoxidation to CO2.Direct conversion of CH4 and O2 at low temperatures or even at room temperature is an appealing strategy for CH4 conversion. However, it is challenging due to the difficulty in continuous formation of active oxygen species under mild conditions for C-H activation.In situ characterizations and theoretical calculations demonstrated that the unique binuclear molybdenum (bi-Mo) site of sulfur vacancies at the MoS2 edge was able to directly dissociate O2 to form O=Mo=O* active species at 25 oC, which could activate the C-H bond of CH4 and thereby driving the catalytic conversion of CH4 to C1 oxygenates via CH3O* intermediates at room temperature.In this study, the researchers achieved CH4 conversion of up to 4.2% with a high selectivity of over 99% for the C1 oxygenates for CH4 conversion by O2 at room temperature.This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China and the Strategic Priority Research Program of CAS.