Converting CO2 to value-added chemicals driven by renewable energy is a strategy of reducing carbon emission and alleviating pressure from depleting fossil resources. Electrocatalytic CO2 reduction (CO2R) to CO is an important way for CO2 utilization since CO is widely used for chemical synthesis.
　　Metal-free nitrogen-doped (N-doped) carbon material possesses high conductivity and tunable electronic structure. It exhibits excellent performance for the electrocatalytic CO2R to CO. However, the active site for the reaction remains under debate due to the complexity in the N species as well as the lack of methods for controllable doping of N.
　　Recently, a research group led by Prof. DENG Dehui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) unveiled the nature of the active site in N-doped carbon materials for the electrocatalytic CO2R to CO. The study was published in Cell Reports Physical Science on August 12.
　　Electrocatalytic performances of N-doped carbon foam on the CO2R to CO reaction (Image by (Text by ZHANG Zheng, YU Liang, and GAO Hehua) 
　　Via an innovated approach of silicon dioxide nanosphere template-assisted pyrolysis of phthalocyanine, the scientists prepared a series of N-doped carbon foam catalysts with precisely controlled N-dopant types and contents.
　　Electrochemical tests showed that at -0.5 V versus reversible hydrogen electrode (RHE), the catalyst dominated by graphitic N (GN) dopants exhibited the highest CO Faradaic efficiency of 95%, compared with those dominated by pyridinic N (PN) or pyrrolic N (ProN) dopants.
　　Theoretical calculations demonstrated that the limiting potentials for CO2R to CO over the carbon atoms adjacent to the GN were significantly lower than those for the hydrogen evolution reaction (HER), which favored the electrocatalytic CO2R.
　　The PN site tended to be blocked by the strongly adsorbed H* and the carbon atoms neighbouring to the PN possessed lower limiting potentials for HER, while the ProN disfavored both CO2R and HER.
　　"Compared with the PN and ProN, the GN significantly improved the activity of the adjacent carbon atoms for the electrocatalytic CO2R to CO," said Prof. DENG.
　　This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Strategic Priority Research Program of Chinese Academy of Sciences, the DNL Cooperation Fund, CAS, and Collaborative Innovation Center of Chemistry for Energy Materials (2011.iChEM). (Text by ZHANG Zheng, YU Liang, and GAO Hehua)

　　Electronics with the merits of flexibility and stretchability are changing our daily life. These technologies have already been applied in wearable sensors and commercial flexible displays. However, commercially available power sources, including thin-film batteries and supercapacitors, are oversized for these devices.
　　In order to fulfill the requirements of flexible electronics with multifunctional properties, one general strategy is to integrate energy harvester, energy storage units, and working units together as an all-in-one system on one substrate.
　　Recently, Prof. WU Zhongshuai from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and Dr. LEI Weiwei from Deakin University reviewed the latest advances in micro-supercapacitor (MSC) powered integrated system for flexible electronics.
　　This work was published in Energy Storage Materials on July 15.
　　Micro-supercapacitors Powered Integrated System for Flexible Electronics (Image by ZHANG Liangzhu)
　　MSCs share a charge storage process via fast ion absorption/desorption or quick and reversibly redox reactions and are designed by in-plane structure, contributing to high power density, long-life span, and excellent integratablity. MSCs are considered as promising on-chip energy storage units for flexible electronics.
　　The scientists investigated the fundamentals of flexible MSCs including planar and sandwich configuration of MSCs, 1D nanomaterials, 2D nanomaterials, and 3D nanocomposites electrode materials, different kinds of gel polymer electrolytes, fabrication technologies, and performance evaluation metrics.
　　They reviewed the MSCs powered integrated systems for flexible electronics with multifunction of photodetection, gas sensing, motion monitoring, body fluid monitoring, and lighting micro-LED.
　　Moreover, they discussed the challenges and opportunities for industry manufacturing technology and practical applications of micro-supercapacitors based integrated systems.
　　This work was supported by National Key R&D Program of China and Dalian National Laboratory for Clean Energy of CAS. (Text by ZHANG Liangzhu)

　　The investigation of diverse carbon-sulfur (C-S) bond activation by transition-metal catalysts can provide fundamental understanding of the C-S bond cleavage in organosulfur compound-involved cross-couplings. C-S bond cross-coupling has become more and more attractive as an alternative protocol to establish carboncarbon and carbonheteroatom bonds.
　　By designing suitable catalyst systems, desulfitative cross-coupling of organosulfur compounds can be rendered catalytic. As more and more efforts are devoted to CS transformations, organosulfur compounds are becoming a class of versatile coupling partners. Diverse transformations through transition-metal-catalyzed CS bond activation and cleavage have recently been developed.
　　Recently, a research group led by Prof. YU Zhengkun and Prof. ZHOU Yonggui from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences reviewed transition-metal mediated carbon-sulfur bond activation and transformations. This study was published in Chem. Soc. Rev. on May 27.
　　This review summarized the advances in transition-metal-catalyzed cross-coupling via carbonsulfur bond activation and cleavage since late 2012. It was presented by the categories of organosulfur compounds as well as the mechanistic insights.
　　The scientists briefly introduced the overview of CS bond cleavage reactions with stoichiometric transition-metal reagents. And discussed theoretical studies on the reactivity of carbonsulfur bonds by DFT calculations.
　　Transition-metal mediated carbon–sulfur bond activation and transformations: an update (Image by WU Kaikai)
　　This work was supported by the National Natural Science Foundation of China. (Text by WU Kaikai)

　　Single-atom-site (SAS) catalysts have important applications in electrocatalysis and organic synthesis.
　　Recently, Prof. DING Yunjie and his colleagues from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences reported a series of porous organic ligand polymers (POLs) supported SAS Pd catalyst. It showed remarkable catalytic performance in distannylation reactions.
　　The enrichment of the substrates by the pores, ligand action of the support, and high chemoselectivity and anti-agglomeration of SAS catalysts were the most striking features of this SAS catalyst.
　　Distannylation of alkynes is very useful in drug synthesis and the construction of complex molecules. In the past, only a few terminal alkynes could be achieved selective distannylation.
　　Based on the mechanism of this reaction, the researchers designed and prepared the porous organic polymer catalyst with triarylphosphonate as the backbone with advantages including pore enrichment, ligand regulation and single atom selective regulation.
　　This catalyst solved all the problems in this reaction such as narrow substrate scope, poor selectivity, and low catalytic efficiency.
　　Different from common carbon-based material, the developed POL support was abundant in phosphate coordination sites with special electrical properties that played a key role in stabilizing the Pd atoms at single atomic sites.
　　The as-fabricated Pd@POL-5 catalyst displayed superior catalytic activity and selectivity in distannylation of various weak electronically terminal alkynes. The selectivity and catalytic performance were much higher than those of any other heterogeneous or homogenous protocols reported in the literature.
　　Scientists creates new reaction route for distannylation of terminal alkynes. (Image by WANG Guoqing and JIANG Miao）
　　This catalytic system offers an effective strategy to use pores, ligands, and single-atom metal sites for synergistic controlling reaction paths.
　　The study was published in Chem on July 29.（Text by WANG Guoqing and JIANG Miao）

　　Synthesis of supported PdAu BNPs (monolith) using nanoreactor strategy. (Image by TIAN Zhengbin)
　　Supported bimetallic catalysts are an important class of catalysts in heterogeneous catalysis. They can be applied in various fields, such as electrocatalysis, biomass conversion, and hydrogen production.
　　However, traditional impregnation and immobilization methods for synthesizing supported bimetallic nanoparticles (BNPs) are often uncontrollable, thus creating BNPs with non-uniform particle size, low alloy degree and inhomogeneous distribution on the supports. The result is poor catalytic performance and low metal utilization.
　　To improve the performance and efficiency of the supported BNPs, Prof. WANG Guanghui and Prof. JIANG Heqing from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. LIU Jian from the Dalian Institute of Chemical Physics (DICP) of CAS, recently proposed a nanoreactor strategy for scalable synthesis of the supported ultrafine BNPs.
　　This strategy introduces high-quality seeds (Pd nanoclusters) and Au ions into the nitrogen-doped mesoporous polymer (NMP). The NMP is used as a nanoreactor for the seeded growth of PdAu BNPs in solid state during thermal reduction.
　　"The synthesized Pd1Au1/4 BNPs are very uniform in diameter with an error of 0.5 nm, and are homogeneously dispersed in the NMP support," said Prof. WANG.
　　The Pd1Au1/4/NMP sample showed enhanced catalytic performance in formic acid (FA) dehydrogenation compared with the monometallic analogs Pd/NMP and Au/NMP.
　　"The enhanced activity can be attributed to the electronic interaction between Pd and Au in the Pd1Au1/4 BNPs. In addition, the electronic interaction could be adjusted by changing the composition of PdAu BNPs during synthesis," said Prof. JIANG.
　　Moreover, the PdAu/NMP product can be molded into a monolith by a pellet press under mild pressure (1.0 bar) without any binders, due to its coral-like structure. The monolith contains abundant macropores which can be of benefit for mass transfer in a liquid reaction.
　　Notably, the monolith of Pd1Au1/4/NMP still exhibits considerable activity in FA dehydrogenation with a TOF value of 3684 h-1 at 333 K, and can be recycled five times without mass loss and changes in activity.
　　Many other supported Pd-based BNPs (diameters ranging from 2-3 nm) have also been synthesized using this method, including PdRu, PdCo, PdNi, PdZn, PdAg and PdCu BNPs.
　　This proposed nanoreactor strategy provides an effective route for synthesizing various supported bimetallic catalysts. These catalysts are promising for applications in green and sustainable catalytic processes.
　　This study was published in Materials Today on July 30. (Text by TIAN Zhengbin)

　　Alkali-metal anodes are considered as ideal anodes for high-energy-density batteries due to their high theoretical capacities and low redox potential.
　　However, the undesirable growth of dendrite and infinite relative change of volume during cycling processes have blocked the commercialization of alkali-metal anodes.
　　Researchers led by Prof. WU Zhongshuai in collaboration with Prof. LI Xianfeng, Dr. ZHENG Qiong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, and Prof. YU Yan from University of Science and Technology of China, developed flexible three-dimensional (3D) MXene/Melamine foam (MXene-MF) with high electronic conductivity for alkali-metal anode with ultrahigh current density and capacities.
　　The study was published in ACS Nano on June 12.
　　The scientists took advantages of high conductivity and lithiophilic surfaces from MXene, in combination of porous, lightweight and flexible nature from 3D MF to develop the MXene-MF.
　　It possessed 3D interconnected porous conductive network and showed good mechanical flexibility and strength, enabling a highly dense and homogenous alkali-metal deposition and suppressing volume fluctuation at both high current density and deposition capacity. Consequently, it achieved a high current density of 50 mA/cm2 for 50 mAh/cm2 for Li anode, and realized a high areal deposition capacity of 20 mAh/cm2 for Na anode.
　　Theoretical simulation demonstrated that the MXene-MF electrode could significantly reduce current density and guide the lithium ions deposition on the MXene skeleton. Moreover, such a robust 3D architecture guaranteed the repeated cycling without decomposing the structural integrity.
　　By pairing MXene-MF-Li with sulfur and MXene-MF-Na with Na3V2(PO4)3, respectively, the assembled full-batteries showed improved cycling and rate capability. MXene-MF is promising in constructing high-energy-density batteries.
　　Schematic of 3D MXene-MF foam for high current-density, high-capacity alkali-metal anodes (Image by SHI Haodong and HOU Xiaocheng)
　　The study was supplied by National Natural Science Foundation of China, National Key R&D Program of China, Dalian National Laboratory For Clean Energy (DNL), CAS. (Text by SHI Haodong and HOU Xiaocheng)