A research group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has reported the efficient near-infrared photon upconversion sensitized by lead-free semiconductor nanocrystals, and demonstrated its novel application in solar synthesis.
　　The study was published in Nature Photonics on Feb. 6.
　　Near-infrared photon upconversion and solar synthesis using lead-free nanocrystals (Image by DU Jun)
　　Upconversion of near-infrared photons to visible photons can boost the performance of photovoltaics, photoredox-catalysis and phototheranostics. Sensitized triplet-fusion is a promising means for photon upconversion.
　　However, current photosensitizers capable of near-infrared absorption often contain either precious or toxic elements, for example, palladium- or platinum-complexes and lead chalcogenide nanocrystals.
　　In this study, the researchers reported zinc-doped CuInSe2 nanocrystals as a low-cost and environmentally-benign sensitizer for near-infrared-to-visible upconversion, which achieved external quantum efficiency of 16.7% for this spectral range.
　　This upconversion system was further merged with photoredox catalysis, enabling reductive dehalogenation, amine oxidation, carbon-oxygen bond formation and photopolymerization efficiently driven by near-infrared photons.
　　More importantly, thanks to the broadband light capturing of the near-infrared nanocrystals, these reactions were remarkably rapid under indoor sunlight, enabling, for example, polymerization of acrylates within just 30 seconds.
　　"Organic synthesis under sunlight, or solar synthesis, has been a century-long idea, which was pioneered by Ciamician et al. But organic chemists' vision has been limited to utilizing visible photons in sunlight," said Prof. WU. "Our study extends the reach of solar synthesis to both visible and near-infrared photons abundant in sunlight, which is poised to strongly boost this technology."

A research group led by Profs. BAO Xinhe, WANG Guoxiong and GAO Dunfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has revealed the mechanism of coverage-driven selectivity switch from ethylene to acetate in high-rate CO2/CO electrolysis.The study was published in Nature Nanotechnology on Jan. 12.Electrolysis of CO2 to valuable chemicals and fuels with power supply derived from renewable energy has emerged as a promising carbon capture, utilization, and storage technology.To push the CO2 electrolysis process towards practical application, high selectivity of multicarbon (C2+) products at industrial current densities is highly desirable. Moreover, tuning the microenvironments near catalyst surfaces has also been demonstrated to be effective in facilitating C–C coupling and improving C2+ production.In this study, the researchers tuned the catalyst microenvironment using mixed CO/CO2 feeds that were typical composition of waste gases from steel plants and incomplete industrial combustion of fossil fuels. Specifically, they investigated CO/CO2 co-electrolysis over a nanoporous CuO nanosheet catalyst in an alkaline membrane electrode assembly (MEA) electrolyzer at high current densities."With increasing CO pressure in the feed, the major product gradually shifted from ethylene to acetate and the current density remarkably increased, up to 3.0 A cm-2 under 0.6 MPa pure CO feed," said Prof. WANG."The selectivity switch was induced by *CO coverage and local pH. Ethylene was preferentially generated at low *CO coverage, whereas acetate formation was favorable at high *CO coverage and high local pH," said Prof. GAO.The researchers further improved electrolysis performance by optimizing electrolysis conditions. The Faradaic efficiency and partial current density of C2+ products reached 90.0% and 3.1 A cm-2, corresponding to a carbon selectivity of 100.0% and yield of 75.0%, outperforming thermocatalytic CO hydrogenation.The scale-up of the CO electrolysis process was demonstrated using an electrolyzer stack composed of four 100 cm2 MEAs, with the highest ethylene formation rate of 457.5 mL min-1 at 150 A and acetate formation rate of 2.97 g min-1 at 250 A."Our work highlights the promise of tuning catalyst microenvironments for selective production of single C2+ products such as acetate and ethylene, and presents an effective scale-up demonstration of high-rate CO2/CO electrolysis towards practical application," said Prof. WANG.

　　Embargo时间为12 January 2023 at 11:00 (US Eastern Time)
　　A research group led by Prof. BAO Xinhe, Prof. WANG Guoxiong and Prof. GAO Dunfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) recently revealed the coverage-driven selectivity switch from ethylene to acetate in high-rate CO2/CO electrolysis towards practical application.
　　The study was published in Nature Nanotechnology on January 12.
　　The performance of CO2/CO electrolysis and the photograph of electrolyzer stack (Image by GAO Dunfeng and WANG Guoxiong)
　　The CO2 electrolysis to valuable chemicals and fuels with power supply derived from renewable energy has emerged as an emerging carbon capture, utilization, and storage (CCUS) technology.
　　To push the CO2 electrolysis process towards practical application, achieving high selectivity of multicarbon (C2+) products at industrial current densities is highly desirable. In addition to rational catalyst design, tuning the microenvironments near catalyst surfaces has also been demonstrated to be effective in facilitating C–C coupling and improving C2+ production.
　　In this study, the researchers tuned the catalyst microenvironment using mixed CO/CO2 feeds which were typical composition of waste gases from steel plants and incomplete industrial combustion of fossil fuels. Specifically, they investigated CO/CO2 co-electrolysis over a nanoporous CuO nanosheet catalyst in an alkaline membrane electrode assembly (MEA) electrolyzer at high current densities.
　　They found that with increasing CO pressure in the feed, the major product gradually shifted from ethylene to acetate and the current density remarkably increased, up to 3.0 A cm-2 under 0.6 MPa pure CO feed.
　　Mechanistic studies indicated that the selectivity switch was induced by *CO coverage and local pH. Ethylene was preferentially generated at low *CO coverage, whereas acetate formation was favorable at high *CO coverage and high local pH.
　　Inspired by the mechanistic understanding, the researchers further improved electrolysis performance by optimizing electrolysis conditions. The Faradaic efficiency and partial current density of C2+ products reached 90.0% and 3.1 A cm-2, corresponding to a carbon selectivity of 100.0% and yield of 75.0%, outperforming thermocatalytic CO hydrogenation. The scale-up of the CO electrolysis process was demonstrated using an electrolyzer stack composed of four 100 cm2 MEAs, with the highest ethylene formation rate of 457.5 mL min-1 at 150 A and acetate formation rate of 2.97 g min-1 at 250 A.
　　"Our work highlights the promise of tuning catalyst microenvironments for the selective production of single C2+ products such as acetate and ethylene, and presents an effective scale-up demonstration of high-rate CO2/CO electrolysis towards practical application," said Prof. WANG.
　　This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Dalian National Laboratory for Clean Energy, the CAS, the Natural Science Foundation of Liaoning Province, the High-Level Talents Innovation Project of Dalian, and the Photon Science Center for Carbon Neutrality. (Text by GAO Dunfeng and WANG Guoxiong)

　　A research group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences (CAS) recently reported the successful initialization, coherent quantum-state control, and readout of spins at room temperature using solution-grown quantum dots, which represents an important advance in quantum information science.
　　The study was published in Nat. Nanotechnol. on Dec 19th.
　　Quantum information science is concerned with the manipulation of the quantum version of information bits (called qubits). When people talk about materials for quantum information processing, they usually think of those manufactured using the most cutting-edge technologies and operating at very cold temperatures (below a few Kelvin), not the "warm and messy" materials synthesized in solution by chemists. Recent years have witnessed the discovery of isolated defects in solid-state materials (such as NV centers) that have made possible room-temperature spin-qubit manipulation, but scaled-up production of these "point defects" will eventually become a challenge.
　　Colloidal quantum dots (QDs), which are tiny semiconductor nanoparticles made in solution, could be a game changer. They can be synthesized in large quantities in solution at low cost, yet with high finesse in size and shape control. Further, they are usually strongly quantum-confined, thus their carriers well isolated from the phonon bath, which could enable long-lived spin coherence at room temperature. But room-temperature coherent manipulation of spins in colloidal QDs has never been reported, in that a QD system whose spins can be simultaneously initialized, rotated, and readout at room-temperature remains to be invented. 
　　Here the authors show that solution-grown CsPbBr3 perovskite QDs can actually accomplish this intimidating goal. Polarized hole spins are obtained by sub-picosecond electron scavenging, to surface-anchored molecular acceptors, following a circularly-polarized femtosecond pulse excitation. A transverse magnetic field induces coherent Larmor precession of the hole spins. A second off-resonance femtosecond pulse coherently rotates the spins through the optical Stark effect, which is enabled by the exceptionally strong light-matter interaction of the perovskite QDs. These results represent full quantum-state control of single-hole spins at room temperature, holding great promise for a scalable and sustainable future of spin-based quantum information processing
　　"Our success here is enabled by a very rare combination of knowledge in materials, chemistry and physics," said Prof. WU. "We fabricated strongly- and uniformly-confined CsPbBr3 QDs as the unique system for the study, and identified appropriate surface-ligand molecules to rapidly extract the electrons via charge-transfer chemistry for hole-spin initialization at room temperature. Meanwhile, we were able to utilize strong light-matter interaction of these QDs to perform coherent spin manipulation." 
　　This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology of China and the National Natural Science Foundation of China. (Text by WU Kaifeng)

Transition metal carbides have attracted much attention due to their unique catalytic properties similar to precious metals. Among them, α-phase molybdenum carbides (α-MoC1-x) shows high activity in activation of water at an ultra-low temperature in water–gas shift and aqueous-phase reforming of methanol reaction.However, the preparation process of cubic α-MoC1-x generally requires an extra ammonification treatment with high energy-consumption or an assistance by significant amount of precious metals, which severely limits its application.Recently, a joint research team led by Prof. SUN Jian, Dr. YU Jiafeng, and Dr. LIU Yuefeng from the Dalian institute of chemical physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Grunwaldt from Karlsruhe Institute of Technology (KIT) of Germany, observed the dynamic evolution of crystal structure at the atomic level, which confirmed that the cubic MoOx phase was the key intermediate for the synthesis of face-centered cubic α-MoC1-x by one-step carburization process.This work was published in Journal of American Chemical Society on Nov. 23 and was selected as a supplementary cover.In situ investigations on structural evolutions during the facile synthesis of cubic α-MoC1–x catalysts (Image by YU Jiafeng)The researchers conducted qualitative and quantitative analyses of crystal phases formed as intermediates during the carburization process, and further monitored the evolution of morphology and crystal structure by environmental transmission electron microscopy.They found that MoO3 was first reduced to cubic oxygen-deficient Mo oxide (MoOx) at a low temperature (300°C) due to the activation of H2 by a trace amount of Rh. Then, carbon atoms could occupy the oxygen vacancies to form cubic MoOxCy intermediates, which were essential to further transformation to α-MoC1–x via the topological route. The final phase of carbides depended on the primary structure of initial intermediates and the route of structural evolution during the carburization process, where a slow and stepwise reduction was necessary for the formation of active α-MoC1–x."This work reveals the key factor of structural evolution during the carburization process," said Prof. SUN. "It provides a more facile and universal strategy for the one-step synthesis of α-MoC1–x." (Text by YU Jiafeng)

　　Microscale electrochemical energy storage systems with high systemic performance, superior cell number density, tunable capacitance, and output voltage are promising for miniaturized electronics.
　　A joint research team led by Prof. WU Zhong-Shuai and Prof. LU Yao from the Dalian institute of chemical physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. CHENG Huiming's group from Shenzhen Institute of Advanced Technology and the Institute of Metal Research of CAS, has developed monolithic integrated micro-supercapacitors with ultrahigh systemic volumetric performance and areal output voltages.
　　This study was published in National Science Review on Nov. 26.
　　The fabrication and electrochemical characterization of M-MIMSCs (Image by WANG Sen and LI Linmei)
　　On-chip interdigitated micro-supercapacitors (MSCs), free of separators and external metal connection wires and simultaneously with reliable electrochemical performance and tunable connection, can boost cell number density and systemic performance for monolithic integrated MSCs (MIMSCs) with desirable customizability in a limited space.
　　However, scalable production of fully-functioning compact MIMSCs with high systemic performance, superior cell number density and tunable performance is still challenging. This is due to the difficulty of precise deposition of electrolytes on densely-packed MSCs for electrochemical isolation, sacrifice in electrochemical performance during complex microfabrication procedures, and limited performance uniformity among numerous individual cells in large scale arrays.
　　In this study, the researchers developed a universal and large-throughput microfabrication strategy to address the above issues by combining multi-step lithographic patterning, spray printing of MXene microelectrodes, and controllable three-dimensional (3D) printing of gel electrolytes.
　　They fabricated the monolithic integration of electrochemically isolated micro-supercapacitors in closely proximity by leveraging high-resolution micropatterning techniques for microelectrode deposition and 3D printing for precise electrolyte deposition.
　　They obtained the MIMSCs with a high areal number density of 28 cells cm-2 (400 cells on 3.5×4.1 cm2), a record areal output voltage of 75.6 V cm-2, an acceptable systemic volumetric energy density of 9.8 mWh cm-3, and a high-capacitance retention of 92 % after 4,000 cycles at the output voltage of 162 V.
　　"This work paves the way for monolithic integrated and microscopic energy storage assemblies for powering future microelectronics," said Prof. WU.
　　This work was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of CAS, Dalian Innovation Support Plan for High Level Talents, and the China Postdoctoral Science Foundation. (Text by WANG Sen and LI Linmei)