A research group led by Prof. WANG Suli and Prof. SUN Gongquan from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Science (CAS) constructed uneven phosphoric acid interfaces within the nanofiber electrode for the high temperature polymer electrolyte fuel cells (HT-PEFCs), which reduce the resistance of oxygen transport.
　　This study was published in Science Advances on January 25.
　　Manufacture, storage, and delivery of the highly purified hydrogen are challenges for the commercialization of PEFCs. Elevated temperature (>150oC) can realize PEFCs fed with hydrogen-rich product reformed from liquid fuels, which is expected to solve the problem of fuel storage and transportation.
　　However, insufficient performance with relatively inferior specific power limits the widespread application of HT-PEFCs. Different from the low temperature-PEFCs (LT-PEFCs), liquid phosphoric acid (PA) is adopted to form a proton-conductive phase and electrochemical interfaces within the porous electrodes of HT-PEFCs, leading to ultrahigh mass transport resistance and catalyst poisoning.
　　In order to reduce mass transport resistance for HT-PEFCs, the researchers designed uneven PA interfacial layers with dispersed droplets by constructing the fibrous electrode architecture. Due to the ultra-hydrophobic nature of the nanofiber networks, PA agglomeration occured as forms of non-infiltration droplets in the size of micrometer scale, which is different from the traditional immersion model of PA under working circumstances.
　　This uneven distribution of PA provided reduced thickness and coverage of the PA layers on the surface of catalyst within the porous electrode, leading to a 32% decrease in oxygen interfacial transport resistance and much enhanced electrochemical surface area compared to that of the conventional one.
　　As a result, the peak power density of the fibrous electrode reached 414 mW cm-2, 28% greater than that of the conventional porous electrode, demonstrating great application potential of HT-PEFCs.
　　This work was supported by the National Nature Science Foundation of China, the National Key Research and Development Program of China, the Foundation of the Key Laboratory of CAS, and DICP.

　　Hydrogen spillover depicts the dynamic migration of surface adsorbed hydrogen species from hydrogen-rich sites to hydrogen-poor sites. It plays an important role in many H-involving reaction processes.
　　In order to enhance the catalytic performance of H-involving reactions, it is important to understand the detailed mechanism of hydrogen spillover, and uncover how hydrogen transfers and what factors control hydrogen conductivity on solid surface.
　　Recently, a research team led by Prof. MU Rentao and Prof. FU Qiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) directly observed the acceleration of hydrogen spillover via surface-lattice-confinement effect.
　　This work was published in Nature Communications on February 04.
　　Schematic of high pressure scanning tunneling microscopy (HP-STM) using a STM tip to probe the hydrogen spillover on MnO and Mn3O4 surfaces in H2 atmosphere (Image by MU Rentao and LIU Yijing)
　　The researchers constructed stripe-like MnO(001) and grid-like Mn3O4(001) monolayers on Pt(111) substrate, and investigated their hydrogen spillover atop by a combination of surface science investigation and theoretical calculation.
　　They found that hydrogen species from Pt diffused unidirectionally along the stripes on MnO(001), whereas it exhibited an isotropic pathway on Mn3O4(001).
　　Moreover, by using dynamic surface imaging in H2 atmosphere, they revealed that hydrogen diffused four times more rapidly on MnO than the case on Mn3O4, which was promoted by one-dimension surface-lattice-confinement effect.
　　Theoretical calculations indicated that a uniform and medium O-O distance favored hydrogen diffusion while low-coordinate surface O atom inhibited it.
　　"Our study illustrates the surface-lattice-confinement effect of oxide catalysts on hydrogen spillover and provides a promising route to improve the hydrogen spillover efficiency." said Prof. FU.
　　This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and Photon Science Center for Carbon Neutrality.

　　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)