Research Progress----Shanghai Advanced Research Institute,Chinese Academy of Sciences

Researchers Develop Ultrahigh-water-flux Membranes for Seawater Desalination

Recently, a research group led by Prof. ZENG Gaofeng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences collaborated with Prof. SHI Guosheng at Shanghai University developed graphdiyne composite membranes which achieve nearly complete salt rejections and ultrahigh-water-flux in the seawater desalination.The results were published in Nature Water on September. 4th.

The supply-demand imbalance of clean water results in a global sustainability crisis. The United Nations World Water Developments Report 2023 reveals that 2-3 bn populations are suffering from the water shortage.
　　Seawater desalination via membrane separation to clean water offers us a cutting-edge and reliable approach to quench our thirsty world. However, most membranes are restricted by the low water flux because the membrane quality is challenged by the harsh conditions and/or the complex process in preparation, which lead to low water productivity, energy efficiency and membrane usage. Thus, it is essential to develop desalination membranes with high-flux.
　　Recently, a research group led by Prof. ZENG Gaofeng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences collaborated with Prof. SHI Guosheng at Shanghai University developed graphdiyne composite membranes which achieve nearly complete salt rejections and ultrahigh-water-flux in the seawater desalination.
　　The results were published in Nature Water on September. 4th.
　　In this work, the submicron thick and nanopore structured graphdiyne membranes on porous Cu hollow fibers are fabricated directly from monomer of hexaethynylbenzene via the Glaser-Hay cross-coupling reaction under mild solvothermal conditions.
　　The graphdiyne membranes exhibited >99.9% rejections to the small ions of seawater and 1-3 orders of magnitude higher water fluxes than commercial membranes, such as zeolite membranes, metal-organic frameworks membranes and graphene-based membranes.The graphdiyne membranes also exhibited reliable stability in the long-term tests with hypersaline water, real seawater and pollutant-containing waters
　　The theoretical calculations suggested that the interfaces of saline-water/graphdiyne and saline-water/vapor contain 1-3 molecular layers of pure water without salt, which contributed to the complete salt rejections on graphdiyne membrane. Through a two-layered graphdiyne channel model, ultrahigh water fluxes were achieved, which is in line with the experimental observations.
　　These findings not only provide an adaptive method for preparing graphdiyne membranes but also indicate the potential of obtaining other alkadiyne containing membranes under similar methodology, which may be used for membrane separations, ions transfer and energy conversion.
　　Preparation, desalination performance and separation mechanism of graphdiyne membrane (Image by SARI)
　　

2023-09-04 more+

Researchers Reveal Sau3AI Represents a New Subclass of Type IIE Restriction Enzymes by Studying its Crystal Structure

Recently, a research team led by Prof. YU Feng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences and Prof. HE Jianhua at Wuhan University reported a self-activating mechanism that the Sau3AI C-terminal domain opens the N-terminal catalytic domain through allosteric effects to achieve cleavage of DNA-specific sites.The research results were published in the Structure on August. 30th.

　　Sau3AI is a type II restriction enzyme widely used for genetic manipulation, such as genome library construction. Sau3AI consists of two domains, the N-terminal domain (Sau3AI-N) and the C-terminal domain (Sau3AI-C). How these two domains work together to cut DNA remains unclear.
　　Recently, a research team led by Prof. YU Feng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences and Prof. HE Jianhua at Wuhan University reported a self-activating mechanism in which the Sau3AI C-terminal domain opens the N-terminal catalytic domain through allosteric effects to achieve cleavage of DNA-specific sites.
　　The results were published in Structure on Aug. 30.
　　As DNA cleavage activity, Sau3AI cannot be expressed in Escherichia coli, a catalytic site mutant, Sau3AI-E64A, was used for exogenous expression and structural research. The crystal structure of the Sau3AI-E64A mutant reveals that when DNA is not bound, a loop region (333-342) of the C-terminal domain hangs over DNA binding site of N-terminal domain, preventing N-terminal domain from binding to DNA.
　　Analysis of the Sau3AI C-terminal domain and DNA complex structure revealed that the loop region (261-268 and 280-295) of C-terminal domain was significantly altered after binding to DNA, implying that Sau3AI may undergo conformational changes after C-terminal domain binds to DNA. Further gel shift assay was performed on the DNA binding key amino acid residue mutants (K257A, S424A, and T435A) in C-terminal domain to confirm that C-terminal binding DNA plays a crucial role in activating the catalytic activity of N-terminal domain. These results suggest that C-terminal domain activates the enzymatic activity of N-terminal domain through allosteric effects.
　　The researchers suggested that Sau3AI is a type IIE restriction enzyme, but unlike other type IIE restriction enzymes, Sau3AI is monomeric rather than homodimer. This study demonstrates that two different domains in Sau3AI play a similar role to homodimers in other type IIE restriction enzymes, suggesting that Sau3AI represents a new subclass of type IIE restriction enzymes.
　　The structure of Sau3AI C-terminal and DNA complex (image by SARI)
　　

2023-08-28 more+

Researchers Develop Target Therapy of Buried Interface for Highly Efficient Perovskite Solar Cells

A research team at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with researchers from the Southern University of Science and Technology and the City University of Hong Kong, reported a facile and effective strategy that is employed for precisely modulating the buried interface through the incorporation of formamidine oxalate (FOA) in a colloidal SnO2-based ETL.The research results were published in the Advanced Materials on July. 17th.

Perovskite solar cells (PSCs) have become a revolutionary photovoltaic technology, which endows the photovoltaic market with strong competitiveness due to their advantages of high performance, low cost, and easy fabrication of large-scale flexible devices.
　　SnO2 is a commonly used electron transport material for n-i-p PSCs due to its high light transmittance and electron mobility, suitable energy levels, good stability under UV irradiation, and can be processed at low temperatures. The buried interface of perovskite/SnO2 plays a crucial role in achieving high efficiency and stability. However, the non-exposed buried interface is challenging to study and manipulate.
　　Motivated by such a challenge, Dr. JI Xiaofei, the assistant researcher in LU Linfeng team at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with researchers from the Southern University of Science and Technology and the City University of Hong Kong, reported a facile and effective strategy that is employed for precisely modulating the buried interface through the incorporation of formamidine oxalate (FOA) in a colloidal SnO2-based ETL.
　　The research results were published in the Advanced Materials on July. 17th.
　　According to research findings, both formamidinium (FA+) and oxalate ions show a longitudinal gradient distribution in the SnO2 layer, and mostly accumulating at the SnO2/perovskite buried interface. The modified SnO2 exhibits higher Fermi level, which induces the better energy level alignment between perovskite and SnO2-FOA, and helps avoid carrier accumulation at the interface and improves open-circuit voltage.
　　Moreover, the FOA can also modulate the crystal growth of upper perovskite films, which enables high-quality perovskite films with minimized grain boundaries and superior interface contacts.
　　Significantly, FA+ cations and oxalate anions can suppress the VO and Sni defects on the SnO2 surface and the FA+/Pb2+ associated defects at the perovskite buried interface contemporaneously, which contribute to achieve target defect passivation. Ultimately, the FOA-modified buried interface significantly increases the champion PCE to 25.05% with enhanced stability of corresponding devices under light, heat, and moisture conditions.
　　The study provides an in-depth understanding of the perovskite buried interface and an effective target therapy to improve the optoelectronic properties of PSCs.
　　The schematic diagram of modulating interfacial energy level, regulating perovskite crystal growth, and reducing interfacial defects for FOA (Image by SARI)
　　

2023-07-27 more+

Researchers Construct Post-synthetic Modification of Covalent Organic Frameworks for CO2 Electroreduction

A research team at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences constructed a multilevel post-synthetic modification strategy to construct catalytic COFs towards CO2RR with high activity and selectivity. The research results were published in Nature Communications.

Covalent organic frameworks (COFs), which possess ordered pores and high-precision functionalization, are regarded as an ideal class of templates to construct catalysts for electrocatalytic carbon dioxide reduction reaction (CO2RR).
　　The C-N bonds can improve the adsorption of CO2 and ionic skeletons can promote the charge transfer, further enhancing the conductivity. However, directly bottom-up synthesis can hardly realize the co-existence of C-N bonds and ionic frameworks due to the electrostatic repulsion and weak strength of the linkage.
　　Motivated by this challenge, a research team led by Prof. ZENG Gaofeng and Associate Prof. XU Qing at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences constructed a multilevel post-synthetic modification strategy to construct catalytic COFs towards CO2RR with high activity and selectivity. The research results were published in Nature Communications.
　　The catalytic COFs synthesised by the post modification show a maximum turnover frequencie value of 9922.68 h–1 at –1.0 V and the highest faradaic efficiencies of 97.32% at –0.8 V, which are higher than that of the base COF and the single-modified COFs. The electrocatalysis tests and characterizations reveal that C-N bonds can improve the catalytic selectivity and ionic skeleton contributes to higher activity.
　　Furthermore, the theoretical calculations illustrate that the easier formation of immediate *CO from COOH* is the rate determined step, and methyl groups strengthen the electron density.
　　This work provides a deeper understanding of COFs in CO2 reduction reaction. In the meantime, it sheds light on constructing multilevel post-synthetic modification COFs towards tailored activity and high stability.
　　
　　Catalytic covalent organic frameworks with bifunctional roles in oxygen reduction reaction (from O2 to H2O) and oxygen evolution reaction (from H2O to O2) have been first demonstrated by integrating redox-active sites into the Co-porphyrin frameworks. (Image by SARI)
　　

2023-06-29 more+

Scientists Develop a Novel Approach to Support Future Power System

Large-scale clusters of electric vehicles (EVs) are an important reserve measure supporting the construction of new power system. Key technologies towards the reliable and economic operation require collaborative innovation across disciplines and fields.Driven by the increasing needs, a joint research team led by Shanghai Advanced Research Institute of the Chinese Academy of Sciences proposed a novel approach to support future power system towards global net-zero emission target. The results were published in the latest issue of Renewable and Sustainable Energy Reviews.

　　The fundamental solution to achieve the "double carbon" goal is to transform the traditional energy consumption toward a low-carbon environment. Therefore, building a new type of power system with new energy sources can guarantee the low-carbon transformation of energy.
　　Large-scale clusters of electric vehicles (EVs) are an important reserve measure supporting the construction of new power system. Key technologies towards the reliable and economic operation require collaborative innovation across disciplines and fields.
　　Driven by the increasing needs, a joint research team led by Shanghai Advanced Research Institute of the Chinese Academy of Sciences and Nanjing University of Posts and Telecommunications proposed a novel multidisciplinary approach to support future power system towards global net-zero emission target.
　　The results were published in the latest issue of Renewable and Sustainable Energy Reviews.
　　This research group reconciled large-scale electric vehicle clusters into the power grid as a case study, and proposed the framework of interactions with physical flow, behavioral flow and information flow.
　　They first analyzed the physical characteristics of electric vehicle clusters providing power system reserve from the perspectives of performance characteristics, resource aggregation, scheduling strategies, and market mechanisms.
　　Then, the importance of social factors was emphasized and a hybrid simulation technology that integrates human participants and computer multi-agents was proposed, to solve the problem of heterogeneity in users’ decision-marking behavior.
　　In addition, the research group discussed the potential solutions regarding global communication coverage, frequency band interference and avoidance, communication security, and customized priority protection. Based on the perspective of the integration of public/private communication networks with Chinese characteristics, the researchers contrapuntally proposed grant-free transmission strategy, joint differentiated spectrum sensing & frequency hopping scheme, and implicit dimension labeling technique for the challenges above.
　　The research work provides technical support and feasible directions for multiple types of distributed reserve resources such as large scientific installations, office buildings, and industrial and agricultural production loads, which can enhance the flexible regulation capability of future power systems. It also introduces a feasibility guarantee that enables more distributed reserve resources for future power systems in various countries and regions.
　　An illustration of full-domain application of the new electric power system (Image by SARI)
　　

2023-06-21 more+

Novel Approach towards the Fabrication of Artificial GNRs with Pentagon Carbon Embedded

a research team led by Prof. SONG Fei at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a novel approach to precisely fabricate well-defined GNRs with the tailored carbon pentagon embedded inside, supported on the Ag(111) model catalyst. The results were published in Journal of Physical Chemistry Letters entitled "On-Surface Synthesis of Pentagon-Incorporated Graphene-Like Nanoribbons with Multiple Precursors”.

2023-06-16 more+