Selective and efficient catalytic conversion of carbon dioxide (CO2) into value-added fuels and feedstocks provides an ideal avenue to high-density renewable energy storage. An impediment to enabling ...deep CO2 reduction to oxygenates and hydrocarbons (e.g., C2+ compounds) is the difficulty of coupling carbon–carbon bonds efficiently. Copper in the +1 oxidation state has been thought to be active for catalyzing C2+ formation, whereas it is prone to being reduced to Cu0 at cathodic potentials. Here we report that catalysts with nanocavities can confine carbon intermediates formed in situ, which in turn covers the local catalyst surface and thereby stabilizes Cu+ species. Experimental measurements on multihollow cuprous oxide catalyst exhibit a C2+ Faradaic efficiency of 75.2 ± 2.7% at a C2+ partial current density of 267 ± 13 mA cm–2 and a large C2+-to-C1 ratio of ∼7.2. Operando Raman spectra, in conjunction with X-ray absorption studies, confirm that Cu+ species in the as-designed catalyst are well retained during CO2 reduction, which leads to the marked C2+ selectivity at a large conversion rate.
High‐energy‐density lithium (Li) metal batteries suffer from a short lifespan owing to apparently ceaseless inactive Li accumulation, which is accompanied by the consumption of electrolyte and active ...Li reservoir, seriously deteriorating the cyclability of batteries. Herein, a triiodide/iodide (I3−/I−) redox couple initiated by stannic iodide (SnI4) is demonstrated to reclaim inactive Li. The reduction of I3− converts inactive Li into soluble LiI, which then diffuses to the cathode side. The oxidation of LiI by the delithiated cathode transforms cathode into the lithiation state and regenerates I3−, reclaiming Li ion from inactive Li. The regenerated I3− engages the further redox reactions. Furthermore, the formation of Sn mitigates the corrosion of I3− on active Li reservoir sacrificially. In working Li | LiNi0.5Co0.2Mn0.3O2 batteries, the accumulated inactive Li is significantly reclaimed by the reversible I3−/I− redox couple, improving the lifespan of batteries by twice. This work initiates a creative solution to reclaim inactive Li for prolonging the lifespan of practical Li metal batteries.
A triiodide/iodide (I3−/I−) redox couple is introduced with a SnI4 initiator to reclaim inactive Li. The reduction of I3− converts inactive Li into soluble LiI, and the oxidation of LiI by a delithiated cathode realizes the restoration of Li ion in cathode from inactive Li. The regenerated I3− by oxidation engages the further redox reactions.
Serious safety risks caused by the high reactivity of lithium metal against electrolytes severely hamper the practicability of lithium metal batteries. By introducing unique polymerization site and ...more fluoride substitution, we built an in situ formed polymer‐rich solid electrolyte interphase upon lithium anode to improve battery safety. The fluorine‐rich and hydrogen‐free polymer exhibits high thermal stability, which effectively reduces the continuous exothermic reaction between electrolyte and anode/cathode. As a result, the critical temperature for thermal safety of 1.0 Ah lithium‐LiNi0.5Co0.2Mn0.3O2 pouch cell can be increased from 143.2 °C to 174.2 °C. The more dangerous “ignition” point of lithium metal batteries, the starting temperature of battery thermal runaway, has been dramatically raised from 240.0 °C to 338.0 °C. This work affords novel strategies upon electrolyte design, aiming to pave the way for high‐energy‐density and thermally safe lithium metal batteries.
The high reactivity of lithium metal against electrolytes is tamed by introducing a polymer‐rich solid electrolyte interphase in situ on the lithium anode. The fluorine‐rich and hydrogen‐free polymer provides both high thermal and electrochemical stability, enhancing the safety and lifespan of lithium‐LiNi0.5Co0.2Mn0.3O2 pouch cells. The “ignition” temperature of the battery can be increased to 338.0 °C benefiting from excellent electrolyte design.
Aerogels, a type of fascinating material with very low density and high surface area, show many unique properties and unlimited applications. To boost their practical applications, it is necessary to ...develop efficient, controllable, and low‐cost methods to produce high‐performance aerogels on a large‐scale, preferably in a sustainable way. Here, a general strategy is reported for controllable fabrication of a family of carbonaceous nanofiber aerogels (CNFAs) by biomass‐derived nanofibers template‐directed hydrothermal carbonization method. Abundant functional groups are exposed on the surface of the prepared carbonaceous nanofibers. Importantly, in contrast to traditional nature biopolymer‐based aerogels, a superior combination of good recoverability and high strength is achieved for the CNFAs by adjusting the synthetic parameters. The successful synthesis of such fascinating materials provides an excellent platform for design and construction of devices for fast water treatment. The synthetic strategy and sustainable concept presented in this work will open a new way to prepare advanced aerogels with unique properties for wide applications.
Biomass‐derived nanofibers, including amyloid nanofibrils, aminated cellulose nanofibers, and deacetylated chitin nanofibers, are used as templates to direct the hydrothermal carbonization of glucose. The obtained carbonaceous nanofiber aerogels with rigid 3D cross‐linked structures provide an excellent platform for design and construction of powerful devices for fast water purification.
The exploration of extreme environments has become necessary for understanding and changing nature. However, the development of functional materials suitable for extreme conditions is still ...insufficient. Herein, a kind of nacre‐inspired bacterial cellulose (BC)/synthetic mica (S‐Mica) nanopaper with excellent mechanical and electrical insulating properties that has excellent tolerance to extreme conditions is reported. Benefited from the nacre‐inspired structure and the 3D network of BC, the nanopaper exhibits excellent mechanical properties, including high tensile strength (375 MPa), outstanding foldability, and bending fatigue resistance. In addition, S‐Mica arranged in layers endows the nanopaper with remarkable dielectric strength (145.7 kV mm−1) and ultralong corona resistance life. Moreover, the nanopaper is highly resistant to alternating high and low temperatures, UV light, and atomic oxygen, making it an ideal candidate for extreme environment‐resistant materials.
A nacre‐inspired nanopaper is fabricated through an aerosol‐assisted biosynthesis (AABS) strategy. Based on the AABS strategy and biomimetic structure design, the nanopaper has excellent mechanical properties, high dielectric strength, and ultralong corona resistance time. The dielectric‐mechanical comprehensive performance of the nanopaper is far beyond that of various commercial mica papers.
Virtual reality (VR) has made it possible for users to access novel digital experiences. An interesting question that arises in the context of VR is whether it appears or feels different to users ...when different virtual environments are used. This study investigates the effect of VR head-mounted display (HMD) and desktop computer-facilitated VR on users’ sense of presence (spatial presence and immersion) and task-oriented self-efficacy when exposed to an earthquake education VR system. A quasi-experiment design was used with a sample of 96 university students. The results revealed that the VR system had positive impacts on the users’ earthquake preparedness self-efficacy. Although the experiment group (
n
= 39) had repeated experiences, as they first used desktop VR followed by VR HMD for the same content, users indicated a higher sense of spatial presence and immersion while using VR HMD than when using desktop VR. In addition, a VR HMD single-group pre- and posttest experimental design was performed with 20 participants, and the differences between the pretest and posttest measurements of earthquake preparedness and self-efficacy were determined to be significant. The qualitative results reveal that the visual stimulus and motion are relevant in composing the VR experience.
The widespread use of disposable plastic straws cause serious environmental problems and poses potential threats to human health, while paper straws, their most used alternatives, are not so ...satisfactory due to poor mechanical performance and unpleasant user experience. Here, a new kind of edible and microplastic‐free straw made from bacterial cellulose (BC) by biosynthesis is reported. Through the alginate coating, this BC‐based straw achieves better mechanical performance than paper straws and avoids additional adhesives. Owing to the 3D nanofiber network and strong interlayer connection, the comprehensive performance of this BC‐based straw surpasses that of commercially available counterparts, satisfying the requirements for practical use. Of particular note, the edible character provides a better user experience and a new end‐of‐life option for the straws, making the BC‐based straw a healthier and more eco‐friendly substitute for plastic straws.
A sustainable, microplastic‐free, ultrastrong, and edible straw is fabricated through biosynthesis. This bacterial cellulose‐based straw demonstrates great sustainability and excellent mechanical performance, representing an ideal substitute for plastic straws and a powerful competitor for paper straws. The 3D network of bacterial cellulose endows the straw with the ability to carry functional substances like flavor molecules, providing a better user experience.
RGB-T salient object detection (SOD) aims at utilizing the complementary cues of RGB and Thermal (T) modalities to detect and segment the common objects. However, on one hand, existing methods simply ...fuse the features of two modalities without fully considering the characters of RGB and T. On the other hand, the high computational cost of existing methods prevents them from real-world applications (e.g., automatic driving, abnormal detection, person re-ID). To this end, we proposed an efficient encoder-decoder network named Context-guided Stacked Refinement Network (CSRNet). Specifically, we utilize a lightweight backbone and design efficient decoder parts, which greatly reduce the computational cost. To fuse RGB and T modalities, we proposed an efficient Context-guided Cross Modality Fusion (CCMF) module to filter the noise and explore the complementation of two modalities. Besides, Stacked Refinement Network (SRN) progressively refines the features from top to down via the interaction of semantic and spatial information. Extensive experiments show that our method performs favorably against state-of-the-art algorithms on RGB-T SOD task while with small model size (4.6M), few FLOPs (4.2G), and real-time speed (38 fps ). Our codes is available at: https://github.com/huofushuo/CSRNet .
Maximizing hole‐transfer kinetics—usually a rate‐determining step in semiconductor‐based artificial photosynthesis—is pivotal for simultaneously enabling high‐efficiency solar hydrogen production and ...hole utilization. However, this remains elusive yet as efforts are largely focused on optimizing the electron‐involved half‐reactions only by empirically employing sacrificial electron donors (SEDs) to consume the wasted holes. Using high‐quality ZnSe quantum wires as models, we show that how hole‐transfer processes in different SEDs affect their photocatalytic performances. We found that larger driving forces of SEDs monotonically enhance hole‐transfer rates and photocatalytic performances by almost three orders of magnitude, a result conforming well with the Auger‐assisted hole‐transfer model in quantum‐confined systems. Intriguingly, further loading Pt cocatalyts can yield either an Auger‐assisted model or a Marcus inverted region for electron transfer, depending on the competing hole‐transfer kinetics in SEDs.
Taking small‐molecule sacrificial electron donors as models, we found that increasing the driving force monotonically enhances hole‐transfer kinetics of semiconductor quantum wires in an Auger‐assisted model, while it affects the electron transfer parabolically in a Marcus model. This suggests three design principles to maximize hole utilization to boost solar hydrogen production and photo‐oxidation of small molecules in quantum‐confined nanocrystals.
It is highly desirable to convert CO2 to valuable fuels or chemicals by means of solar energy, which requires CO2 enrichment around photocatalysts from the atmosphere. Here we demonstrate that a ...porphyrin-involved metal–organic framework (MOF), PCN-222, can selectively capture and further photoreduce CO2 with high efficiency under visible-light irradiation. Mechanistic information gleaned from ultrafast transient absorption spectroscopy (combined with time-resolved photoluminescence spectroscopy) has elucidated the relationship between the photocatalytic activity and the electron–hole separation efficiency. The presence of a deep electron trap state in PCN-222 effectively inhibits the detrimental, radiative electron–hole recombination. As a direct result, PCN-222 significantly enhances photocatalytic conversion of CO2 into formate anion compared to the corresponding porphyrin ligand itself. This work provides important insights into the design of MOF-based materials for CO2 capture and photoreduction.
