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Researchers Constructed Bifunctional Catalysts with Redox-active Sites for Oxygen Reduction and Oxygen Evolution Reaction

Recently, 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 novel bifunctional COFs towards ORR and OER by combining redox-active units with catalytic centers in the frameworks.

　　It is essential to develop bifunctional oxygen electrocatalysts which exhibit high activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).
　　Covalent organic frameworks (COFs), which possess ordered pores and high-precision functionalization, have been used in electrochemical energy and conversion systems because of their fast ion transport channels and well-defined electrochemical active sites.
　　However, the limited electron transport ability along the frameworks hindered their electroactivities, while the development of active sites in COFs towards ORR and OER is rarely explored.
　　Recently, 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 novel bifunctional COFs towards ORR and OER by combining redox-active units with catalytic centers in the frameworks. The COFs showed higher catalytic activities than that of the COF without redox-active units, with a halfwave potential of 0.80 V towards ORR, and an overpotential of 420 mV for OER in 0.1 M KOH, respectively.
　　The research results were published in Angewandte Chemie International Edition on Oct. 14.
　　Two novel COFs (CoTAPP-PATA-COF and CoTAPP-BDTA-COF) have ordered structure, high surface area and stable chemical stability. The diamine unit, as a typical electron donor and redox-active core, facilitates the electron transport along the framework and improves the electrochemical active surface area.
　　The theoretical calculation results demonstrate that the introduction of diamine units can effectively improve the oxygen electrocatalysis. By tuning the catalytic centers, the CoTAPP-PATA-COF catalyzes the ORR and OER with high activity and stability.This work may shed light on developing catalytic COFs in energy storage and conversion systems.
　　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)
　　

2022-10-19 more+

Researchers Propose a Novel Federated Learning-Based μXRD Image Screening Method

A research group at the Shanghai Advanced Research Institute, Chinese Academy of Sciences unveiled the solutions to improve the screening while protecting data privacy.The results of the physics law-informed federated learning (FL) based μXRD image screening method are published on IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS.

The X-ray microdiffraction (μXRD) in synchrotron radiation facilities are conducted for industrial minerals to identify their crystal impurities. Because of its unique advantages, it can be applied in many services such as client selection strategy, imbalanced data distribution, hybrid training, etc.
　　However, two major problems are hindering the development of accurate μXRD image screening. One is the lack of labeled industrial samples and the other is the privacy concerns of industrial users of μXRD services.
　　To address these problems, a research group led by Professor ZHU Yongxin at the Shanghai Advanced Research Institute, Chinese Academy of Sciences unveiled the solutions to improve the screening while protecting data privacy.
　　The results of the physics law-informed federated learning (FL) based μXRD image screening method are published on IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS.
　　Researchers firstly utilized the domain specific physical information to improve the federated learning accuracy. Then, with the consideration of the unbalanced data distributions in realistic world, they adopted a sampling scheme with novel client sampling algorithms. Thirdly, a hybrid training framework was proposed to deal with the unstable communication environment between FL clients and servers in federated learning.
　　The extensive experiments showed that the accuracy of machine learning models got improved by around 14% to 25% and the data features could be shared among different users or applications while keeping commercially confidential information.This novel system with federated learning features will be helpful in lifting the non-technical barriers on data sharing. It will help to relieve the stress on processing the increasing data volume in the facilities as well as lower the cost of the users of the facilities, thus enhancing the productivities of academic activities and industrial production.
　　Fig. 1. Labelled diffraction images from LN84 and LN498 dataset (Image by SARI)
　　Fig. 2. Improved accuracy in connection with various plug-in models (Image by SARI)
　　

2022-10-17 more+

Researchers Propose a Novel FTO Route with Ultrahigh Carbon Efficiency

A research team led by Prof. ZHONG Liangshu at Shanghai Advanced Research Institute (SARI) of Chinese Academy of Sciences reported a non-classical Fischer-Tropsch to olefins (FTO) process featuring high carbon efficiency that realizes 80.1% olefins selectivity with ultralow total selectivity of CH4 and CO2 (<5%) at CO conversion of 45.8%.

Olefins are key building blocks to manufacture a wide range of value-added products such as polymers, lubricants, plasticizers, drugs, detergent and cosmetics. Syngas conversion serves as a competitive strategy to produce olefins from nonpetroleum resources. However, the goal to achieve desirable olefins selectivity with limited undesired C1 by-products remains a grand challenge.Motivated by such a challenge, a research team led by Prof. ZHONG Liangshu at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a non-classical Fischer-Tropsch to olefins (FTO) process featuring high carbon efficiency that realizes 80.1% olefins selectivity with ultralow total selectivity of CH4 and CO2 (<5%) at CO conversion of 45.8%.The results were published in Nature Communications on 10 October 2022.The researchers prepared a silica-supported Ru nanoparticles catalyst with sodium (Na) as promoter (denoting as Na-Ru/SiO2), which was highly active for FTO reaction but very inactive for water-gas-shift (WGS) reaction.With various characterizations and surface probe reaction experiments, the Ru metal is demonstrated to be the active phase, and the Na promoter can suppress the reactivity of chemisorbed H atoms on Ru surface sites while greatly promote the production of olefins, especially for long-chain α-olefins (C5+=), whose fraction in olefins distribution reached up to 74.5%.No obvious deactivation is observed within 550 hours and the pellet catalyst also exhibits excellent catalytic performance in a pilot-scale reactor, suggesting promising practical applications.The results of this work demonstrate that the modified-metallic Ru can effectively tune the dominated product distribution from traditional paraffins to value-added olefins. The as-obtained catalytic performance exhibits the highest olefins (especial for C5+=) selectivity and yield together with the lowest fraction of undesired C1 by-products including CH4 and CO2, which outperforms the reported results under all the CO conversion levels in the previous references.The ultrahigh selectivity and yield of olefins as well as the limited production of C1 by-products enables a considerable carbon efficiency for the current FTO route, and also represents a big step toward the application of Ru-based catalysts for direct production of olefins, especially for long-chain olefins, from syngas.
　　Catalytic performance for direct syngas conversion to olefins over Na-modified Ru-based catalyst
　　 (Image by SARI)
　　

2022-10-12 more+

Researchers Develop Synergistic Catalysts of Ru single-atoms and Zeolite for High-efficiency Hydrogen Storage

A research team led by Prof. CHEN Xinqing at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a new strategy utilizing Ru single atoms and *BEA zeolite to synergistically catalyze hydrogen storage of liquid organic hydrogen carriers (LOHCs) with superior performance.

Hydrogen energy is regarded as promising renewable energy to deal with the crises of energy resources. However, the development of hydrogen energy is greatly restricted by the safe and efficient storage and transportation of hydrogen. Therefore, it remains a great challenge to explore the feasibility of high-efficiency catalysts with low-cost in hydrogen storage under low temperature.
　　Motivated by such a challenge, a research team led by Prof. CHEN Xinqing at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a new strategy utilizing Ru single atoms and *BEA zeolite to synergistically catalyze hydrogen storage of liquid organic hydrogen carriers (LOHCs) with superior performance.
　　The research results were published in Applied Catalysis B: Environmental.
　　Atomically dispersed Ru supported on *BEA zeolite was prepared by deposition precipitation for LOHCs. It is found that highly dispersed Ru single-atoms boost hydrogen activation and the strong acid sites of zeolites promote the hydrogen spillover on the hydrogenation with N-heterocycles.
　　Moreover, the synergistic effect of Ru single atoms and *BEA zeolite is crucial for accelerating the hydrogenation rate and lowering the activation energy compared with traditional Ru-based catalysts.
　　The synergistic catalysis of Ru single-atoms and zeolite with the assistance of hydrogen spillover exhibited excellent hydrogenation activity of N-ethylcarbazole (NEC), N-propylcarbazole (NPC), and 2-methylindole (2-MID) at lower temperatures with lower Ru content (0.5 wt%).
　　The study of Ru single-atoms and zeolite synergistic catalysis provides a new strategy for the synergetic catalysis of zeolite-supported metal catalysts for fast hydrogen storage into aromatic LOHCs under mild conditions.
　　Hydrogenation performance of N-ethylcarbazole (NEC) of different catalysts and comparison results of literature
　　(Image by SARI)
　　Cotact: CHEN Xinqing
　　Shanghai Advanced Research Institute
　　chenxq@sari.ac.cn
　　

2022-09-28 more+

Researchers Develop a Novel Spectrum Sensing Technique for 6G-Oriented Intelligent IoT Communications

A joint research team creatively proposed a novel spectrum sensing technique for 6g-oriented intelligent IoT communications, seeking a feasible way to provide the underlying support for perceptual interference and intelligent identification between large-scale coexistence and aliasing IoT users in future 6G scenario.

With the explosive growth of the spectrum demand of the Internet of Things (IoT), Non-orthogonal Multiple Access (NOMA) and spectrum sensing are considered to be key candidate technologies to improve spectrum utilization in next generation wireless communications technology.However, given the complexity of future IoT scenarios, it brings new challenges on how to ensure the performance of spectrum utilization and system throughput in large-scale IoT scenarios when using both technologies at the same time.Motivated by such a challenge, a joint research team composed of researchers from Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences (CAS), VTT Technical Research Centre of Finland and University of Windsor (Canada) creatively proposed a novel spectrum sensing technique for 6g-oriented intelligent IoT communications, seeking a feasible way to provide the underlying support for perceptual interference and intelligent identification between large-scale coexistence and aliasing IoT users in future 6G scenario.The research results were published in the latest issue of IEEE Internet of Things Journal.Focused on inter-system orthogonal/non-orthogonal aliasing coexistence scenarios, researchers design a multi-layer spectrum sensing technology based on feature detection in NOMA scenarios with multi-users. The corresponding rational workflows and transceiver structures according to different scenarios are presented, and the threshold expressions are deduced accordingly. Oriented towards the upcoming 6G complicated scenarios, researchers designed one downlink mode and two uplink modes to describe relationships among users’ priorities, power, and transmission forms. Based on the characteristics of each mode, researchers further customized the detection probability optimization algorithm according to the characteristics of each scene, so that the proposed technology can effectively improve the detection probability of orthogonal/non-orthogonal hybrid IoT systems and improve the overall system throughput.Experimental results verify that the proposed spectrum sensing technology is feasible and has prominent detection performance and satisfying throughput performance. This work will promote the theory of signal perception and recognition for 6G-oriented intelligent IoT communications, and will provide technical support and development potentials for the promotion of global 6G strategy.
　　Figure 1. Schematic diagram of downlink hybrid IoT sensing scene and an illustration for frequency band occupancy status (Image by SARI)
　　Figure 2. Schematic diagram of uplink hybrid IoT sensing scene and an illustration for frequency band occupancy status (Image by SARI)
　　

2022-09-27 more+

Researchers Proposed a Facile Tactic to Enhance Electrocatalytic Conversion of Carbon Dioxide

A research team from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a facile tactic that enables exceedingly efficient CO2 electroreduction to CO by virtue of low-coordination chloride ion (Cl-) adsorption on a silver hollow fiber (Ag HF) electrode.

　　The electrochemical conversion of CO2 into carbon-based fuels and valuable feedstocks by renewable electricity is an attractive strategy for carbon neutrality. CO is the key component of syngas, a mixture of CO and H2 that can be directly converted into various value-added chemicals via well-developed industrial processes such as Fischer-Tropsch synthesis, methanol synthesis, etc. Therefore, CO2 electroreduction to CO is considered to be one of the most promising routes to obtain cost-competitive products.
　　However, due to the low solubility and diffusion coefficient of CO2 in aqueous electrolytes, it remains a challenge to possess a large current density, a high faradaic efficiency and excellent stability for practical applications of CO2 utilization.
　　Motivated by such a challenge, a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a facile tactic that enables exceedingly efficient CO2 electroreduction to CO by virtue of low-coordination chloride ion (Cl-) adsorption on a silver hollow fiber (Ag HF) electrode.
　　The results were published in Angew. Chem. Int. Ed. on September 3.
　　On the basis of the high efficient electroreduction CO2 to CO over silver hollow fiber (Ag HF) electrode, the research team further introduced chloride ions into the electrode solution, by means of specific adsorption of chloride ions, the electronic structure of the electrode surface was functionally regulated to inhibit the side reaction of hydrogen evolution (HER).
　　The low-coordination chloride ion (Cl-) adsorption on a silver hollow fiber (Ag HF) electrode reduces CO2 to CO at a stable (>150 h) ampere-level current densities (1 A·cm-2) with a high CO faradaic efficiencies (>92%).
　　Electrochemical experiments, operando Raman combined with density functional theory (DFT) calculations demonstrated that the high concentration Cl- in the electrolyte could be low-coordination adsorbed onto the surface of Ag HF, which not only hinders the occurrence of the HER, but also optimizes the kinetics of CO2 reduction to CO, leading to a better eCO2RR performance, even at the ampere-level current density.
　　This work provides a new strategy for further developing electrocatalytic CO2 systems with high current density, high selectivity and high stability in CO2utilization and chlor-alkali industry.
　　Schematic diagram and electrocatalytic performance of efficient CO2 reduction over silver hollow fiber electrode with chloride ion adsorption (Image by SARI)
　　

2022-09-09 more+

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