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Janus monolayers of transition metal dichalcogenides (TMDs) offer versatile applications due to their tunable polymorphisms. While previous studies focused on conventional 2H-phase Janus monolayers, the scalable synthesis of an unconventional 1T' phase remains challenging. We present a novel solution strategy for fabricating Janus 1T'-MoOSe and MoSSe monolayers by growing sandwiched Se-Mo-O/S shells onto Au nanocores. The Janus Au@1T'-MoSSe catalyst exhibits superior electrocatalytic hydrogen evolution reaction (HER) activity compared to 1T'-MoS2, -MoSe2, and -MoOSe, attributed to its unique electronic structure and intrinsic strain. Remarkably, photoexciting the nanoplasmonic Au cores further enhances the HER via a localized surface plasmon (LSP) effect that drives hot electron injection into surface sulfur vacancies of 1T'-MoSSe monolayer shells, accelerating proton reduction. This synergistic activation of anion vacancies by internal strain and external light-induced Au LSPs, coupled with our scalable synthesis, provides a pathway for developing tailorable polymorphic Janus TMDs for specific applications.
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Salt deposition is a disturbing problem that limits the development of passive solar-driven interfacial evaporation. Inspired by the passive fluid control mechanism of the Tesla valve, a novel solar evaporator is proposed with a Tesla valve-like water transport structure to prevent salt accumulation at the evaporation interface. A unique "ion diode" salt resistance of this evaporator is significantly achieved by optimizing the two asymmetric water transport structures, consisting of one Tesla valve-like side and one wide-leg side, which establish a reverse-suppressing and forward-accelerating water transport channel. In contrast to the limited ion migration of the typical symmetric solar evaporator, such a channel caused by the water/salt ions transport difference between two water supply structures, reinforces the water/salt ions supply on the wide-leg side, thus leading to an apparent unidirectional salt ions migration from the wide-leg side to bulk water through the Tesla valve-like side. Consequently, an evaporation rate of 3.25 kg m-2 h-1 and a conversion efficiency of 83.27% under 2 suns are achieved in 16 wt% NaCl solution. The development of the Tesla Valve-like evaporator provides a new perspective for solving salt deposition and realizing scalable applications of solar-driven interfacial evaporation.
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The negative effect of photoinduced halide segregation (PIHS) on the properties of hybrid halide perovskites poses a major obstacle for its future commercial application. Therefore, the in-depth understanding of halide-ion segregation and its causes is an urgent and intractable problem. When PIHS reaches a certain threshold, it will aggravate the deterioration of the film surface morphology and form nanoscale cracks. Herein, the formation mechanism and types of cracks are revealed by exploring the stress distribution in the film. Using the femtosecond time-resolved transient absorption spectroscopy, the ultrafast formation of the iodine rich phase is observed, which appears earlier than the bromine rich phase. In addition, the introduction of organic ligand didodecyldimethylammonium bromide can significantly inhibit PIHS and improve the surface morphology of the film, which can promote the device efficiency from 9.63 to 11.20%. This work provides a novel perspective for the exploration of the PIHS.
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Solar interfacial evaporation technology has the advantages of environmentally conscious and sustainable benefits. Recent research on light absorption, water transportation, and thermal management has improved the evaporation performance of solar interfacial evaporators. However, many studies on photothermal materials and structures only aim to improve performance, neglecting explanations for heat and mass transfer coupling or providing evidence for performance enhancement. Numerical simulation can simulate the diffusion paths and heat and water transfer processes to understand the thermal and mass transfer mechanism, thereby better achieving the design of efficient solar interfacial evaporators. Therefore, this review summarizes the latest exciting findings and tremendous advances in numerical simulation for solar interfacial evaporation. First, it presents a macroscopic summary of the application of simulation in temperature distribution, salt concentration distribution, and vapor flux distribution during evaporation. Second, the utilization of simulation in the microscopic is summed up, specifically focusing on the movement of water molecules and the mechanisms of light responses during evaporation. Finally, all simulation methods have the goal of validating the physical processes in solar interfacial evaporation. It is hoped that the use of numerical simulation can provide theoretical guidance and technical support for the application of solar-driven interfacial evaporation technology.
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@#Objective To summarize and analyze the epidemiological and clinical characteristics of COVID-19 Omicron variant cases in makeshift hospital, and the influence of age, sex and vaccination status on the disease duration, so as to provide reference for the prevention and control of the COVID-19 epidemic. Methods The epidemiological and clinical characteristics of COVID-19 cases admitted to makeshift hospital of National Convention and Exhibition Center (Shanghai) from April 9 to May 31, 2022 were retrospectively described and analyzed, and further cohort analysis was conducted to determine the influence of age, sex and vaccination status on the disease duration of COVID-19 cases in the author's branch hospital. Results Among the 174 466 COVID-19 cases in makeshift hospital, most of them were male, accounting for 59.38%. The infected cases were mainly young and middle-aged people aged 18-59 years old, accounting for 83.50%, followed by 12.30% of the elderly group over 60 years old; the average hospital stay was 7.40 days; the proportion of patients with fever was less than 27.79%; 15.37% (26 817/174 466) of the patients complicated with underlying diseases, and the top three were hypertension, diabetes and coronary heart disease. The proportion of people who received COVID-19 vaccine accounted for 79.56% (13 799/17 956), of which the highest proportion of three doses was 44.09%. The disease duration of 17 956 COVID-19 cases in the author's branch of makeshift hospital was 10.18 (7.34, 13.05) days. The disease duration in the elderly group was the longest with 11.34 (8.35, 14.37) days, followed by 11.17 (9.07, 14.33) days in the preschool group, 10.37 (8.14, 13.34)· days in the middle-aged group, 10.07 (7.37, 12.37) days in the school-age group, and 9.34 (7.05, 12.16) days in the young group. There was significant difference in the overall distribution of disease duration among the five groups (H=550.479 P<0.01). The disease duration in each age group basically showed a V-shaped distribution. The disease duration was 10.27 (7.34, 12.57) days in males and 10.10 (7.25, 13.09) days in females, and there was no significant difference (Z=-1.505 P>0.05). The disease duration of vaccinated patients was 10.24 (7.35, 13.05) days, and that of unvaccinated patients was 9.47 (7.09, 12.47) days. There was significant difference between the two groups (Z=-4.338 P<0.01). Conclusions COVID-19 Omicron variant cases have a high proportion of males, mainly young and middle-aged, and the proportion of fever patients is less than 30%. The disease duration is significantly lower than that of the original strain in Wuhan, and shows "V" distribution with each age group. Sex had no effect on the disease duration. COVID-19 vaccination did not have a clinical effect on the disease duration.