查看更多>>摘要：Defects formed at the surface,buried interface and grain boundaries(GB)of CsPbI3 perovskite films con-siderably limit photovoltaic performance.Such defects could be passivated effectively by the most preva-lent post modification strategy without compromising the photoelectric properties of perovskite films,but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films.Herein,a spatially selective defect management(SSDM)strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate(PZD(BF4)2)solution.The small-size PZD2+cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI3 perovskite films,while the BF4-anions,with largely different properties from I-anions,mainly anchor on the film surface.Consequently,virtually all the defects at the surface,buried interface and grain boundaries of CsPbI3 perovskite films are effectively healed,leading to significantly improved film quality,enhanced phase stability,optimized energy level alignment and promoted carrier transport.With these films,the fabricated CsPbI3 PSCs based on carbon electrode(C-PSCs)achieve an efficiency of 18.27％,which is among the highest-reported values for inorganic C-PSCs,and stability of 500 h at 85 ℃ with 65％efficiency maintenance.
查看更多>>摘要：Nanosized Pt catalysts are the catalyst-of-choice for proton exchange membrane fuel cell(PEMFC)anode,but are limited by their extreme sensitivity to CO in parts per million(ppm)level,thereby making the use of ultrapure H2 a prerequisite to ensure acceptable performance.Herein,we confront the CO poisoning issue by bringing the Ir/Rh single atom sites to synergistically working with their metallic counterparts.In presence of 1000 ppm CO,the catalyst represents not only undisturbed H2 oxidation reaction(HOR)catalytic behavior in electrochemical cell,but also unparalleled peak power density at 643 mW cm-2 in single cell,27-fold in mass activity of the best PtRu/C catalysts available.Pre-poisoning experiments and surface-enhanced Raman scattering spectroscopy(SERS)and calculation results in combine suggest the presence of adjacent Ir/Rh single atom sites(SASs)to the nanoparticles(NPs)as the origin for this prominent catalytic behavior.The single sites not only exhibit superb CO oxidation performance by themselves,but can also scavenge the CO adsorbed on approximated NPs via supplying reactive OH*spe-cies.We open up a new route here to conquer the formidable CO poisoning issue through single atom and nanoparticle synergistic catalysis,and pave the way towards a more robust PEMFC future.
查看更多>>摘要：The commercialization of lithium-sulfur(Li-S)batteries has been hindered by the shuttle effect and slug-gish redox kinetics of lithium polysulfides(LiPSs).Herein,we reported a viologen-based ionic conjugated mesoporous polymer(TpV-Cl),which acts as the cathode host for modifying Li-S batteries.The viologen component serves as a reversible electron conveyer,leading to a comprehensive enhancement in the adsorption of polysulfides and improved conversion rate of polysulfides during the electrochemical pro-cess.As a result,the S@TpV-PS cathode exhibits outstanding cycling performance,achieving 300 cycles at 2.0 C(1 C=1675 mA g-1)with low decay rate of 0.032％per cycle.Even at a high sulfur loading of 4.0 mg cm-2,S@TpV-PS shows excellent cycling stability with a Coulombic efficiency of up to 98％.These results highlight the significant potential of S@TpV-PS in developing high-performance Li-S batteries.
查看更多>>摘要：Maximally exploiting the active sites of iridium catalysts is essential for building low-cost proton exchange membrane(PEM)electrolyzers for green H2 production.Herein,we report a novel microdrop-confined fusion/blasting(MCFB)strategy for fabricating porous hollow IrO1-xmicrospheres(IrO1-x-PHM)by introducing explosive gas mediators from a NaNO3/glucose mixture.Moreover,the developed MCFB strategy is demonstrated to be general for synthesizing a series of Ir-based composites,including Ir-Cu,Ir-Ru,Ir-Pt,Ir-Rh,Ir-Pd,and Ir-Cu-Pd and other noble metals such as Rh,Ru,and Pt.The hollow structures can be regulated using different organics with NaNO3.The assembled PEM electrolyzer with IrO1-x-PHM as the anode catalyst(0.5 mg/cm2)displays an impressive polarization voltage of 1.593 and 1.726 V at current densities of 1 and 2 A/cm2,respectively,outperforming commercial IrOx catalysts and most of the ever-reported iridium catalysts with such low catalyst loading.More importantly,the breakdown of the polarization loss indicates that the improved performance is due to the facilitated mass transport induced by the hollowness.This study offers a versatile platform for fabricating efficient Ir-based catalysts for PEM electrolyzers and beyond.
查看更多>>摘要：Controlling the atomic arrangement of elemental atoms in intermetallic catalysts to govern their surface and subsurface properties is a crucial but challenging endeavor in electrocatalytic reactions.In hydrogen evolution reaction(HER),adjusting the d-band center of the conventional noble-metallic Pt by introduc-ing Fe enables the optimization of catalytic performance.However,a notable gap exists in research on the effective transition from disordered Fe/Pt alloys to highly ordered intermetallic compounds(IMCs)such as FePt3 in the alkaline HER,hampering their broader application.In this study,a series of catalysts FePt3-xH(x=5,6,7,8 and 9)supported on carbon nanotubes(CNTs)were synthesized via a simple impregnation method,along with a range of heat treatment processes,including annealing in a reductive atmosphere,to regulate the order degree of the arrangement of Fe/Pt atoms within the FePt3 catalyst.By using advanced microscopy and spectroscopy techniques,we systematically explored the impact of the order degree of FePt3 in the HER.The as-prepared FePt3-8H exhibited notable HER catalytic activity with low overpotentials(η=37 mV in 1.0 mol L-1 KOH)at j=10 mA cm-2.The surface of the L12 FePt3-8H catalyst was demonstrated to be Pt-rich.The Pt on the surface was not easily oxidized due to the unique Fe/Pt coordination,resulting in significant enhancement of HER performance.
查看更多>>摘要：Catalytic conversion of nitrate(NO3-)pollutants into ammonia(NH3)offers a sustainable and promising route for both wastewater treatment and NH3 synthesis.Alkali cations are prevalent in nitrate solutions,but their roles beyond charge balance in catalytic NO3 conversion have been generally ignored.Herein,we report the promotion effect of K+cations in KNO3 solution for NO3-reduction over a TiO2-supported Ni single-atom catalyst(Ni1/TiO2).For photocatalytic NO3-reduction reaction,Ni1/TiO2 exhib-ited a 1.9-fold NH3 yield rate with nearly 100％selectivity in KNO3 solution relative to that in NaNO3 solu-tion.Mechanistic studies reveal that the K+cations from KNO3 gradually bonded with the surface of Ni1/TiO2,in situ forming a K-O-Ni moiety during reaction,whereas the Na+ions were unable to interact with the catalyst in NaNO3 solution.The charge accumulation on the Ni sites induced by the incorporation of K atom promoted the adsorption and activation of NO3-.Furthermore,the K-O-Ni moiety facilitated the multiple proton-electron coupling of NO3 into NH3 by stabilizing the intermediates.
查看更多>>摘要：Hydrogen is widely regarded as a sustainable energy carrier with tremendous potential for low-carbon energy transition.Solar photovoltaic-driven water electrolysis(PV-E)is a clean and sustainable approach of hydrogen production,but with major barriers of high hydrogen production costs and limited capacity.Steam methane reforming(SMR),the state-of-the-art means of hydrogen production,has yet to over-come key obstacles of high reaction temperature and CO2 emission for sustainability.This work proposes a solar thermo-electrochemical SMR approach,in which solar-driven mid/low-temperature SMR is com-bined with electrochemical H2 separation and in-situ CO2 capture.The feasibility of this method is veri-fied experimentally,achieving an average methane conversion of 96.8％at a dramatically reduced reforming temperature of 400-500 ℃.The underlying mechanisms of this method are revealed by an experimentally calibrated model,which is further employed to predict its performance for thermo-electrochemical hydrogen production.Simulation results show that a net solar-to-H2 efficiency of 26.25％could be obtained at 500 ℃,which is over 11 percentage points higher than that of PV-E;the first-law thermodynamic efficiency reaches up to 63.27％correspondingly.The enhanced efficiency also leads to decreased fuel consumption and lower CO2 emission of the proposed solar-driven SMR system.Such complementary conversion of solar PV electricity,solar thermal energy,and low-carbon fuel pro-vides a synergistic and efficient means of sustainable H2 production with potentially long-term solar energy storage on a vast scale.
查看更多>>摘要：In a growing follicle,the survival and maturation of the oocyte largely depend on support from somatic cells to facilitate FSH-induced mutual signaling and chemical communication.Although apoptosis and autophagy in somatic cells are involved in the process of FSH-induced follicular development,the under-lying mechanisms require substantial study.According to our study,along with FSH-induced antral fol-licles(AFs)formation,both lysine-specific demethylase 1(LSD1)protein levels and autophagy increased simultaneously in granulosa cells(GCs)in a time-dependent manner,we therefore evaluated the impor-tance of LSD1 upon facilitating the formation of AFs correlated to autophagy in GCs.Conditional knockout of Lsd1 in GCs resulted in significantly decreased AF number and subfertility in females,accompanied by marked suppression of the autophagy in GCs.On the one hand,depletion of Lsd1 resulted in accumulation of Wilms tumor 1 homolog(WT1),at both the protein and mRNA levels,WT1 prevented the expression of FSH receptor(Fshr)in GCs and thus reduced the responsiveness of the secondary follicles to FSH induc-tion.On the other hand,depletion of LSD1 resulted in suppressed level of autophagy by upregulation of ATG16L2 in GCs.We finally approved that LSD1 contributed to these sequential activities in GCs through its H3K4me2 demethylase activity.Therefore,the importance of LSD1 in GCs is attributable to its roles in both accelerating autophagy and suppressing WT1 expression to ensure the responsiveness of GCs to FSH during AFs formation.
查看更多>>摘要：Abnormal hyperphosphorylation and accumulation of tau protein play a pivotal role in neurodegenera-tion in Alzheimer's disease(AD)and many other tauopathies.Selective elimination of hyperphosphory-lated tau is promising for the therapy of these diseases.We have conceptualized a strategy,named dephosphorylation-targeting chimeras(DEPTACs),for specifically hijacking phosphatases to tau to debil-itate its hyperphosphorylation.Here,we conducted the step-by-step optimization of each constituent motif to generate DEPTACs with reasonable effectiveness in facilitating the dephosphorylation and sub-sequent clearance of pathological tau.Specifically,for one of the selected chimeras,D1 6,we demon-strated its significant efficiency in rescuing the neurodegeneration caused by neurotoxic K18-tau seeds in vitro.Moreover,intravenous administration of D1 6 also alleviated tau pathologies in the brain and improved memory deficits in AD mice.These results suggested DEPTACs as targeted modulators of tau phosphorylation,which hold therapeutic potential for AD and other tauopathies.
查看更多>>摘要：Although climate change has convincingly been linked to the evolution of human civilization on different temporal scales,its role in influencing the spatial patterns of ancient civilizations has rarely been inves-tigated.The northward shift of the ancient Silk Road(SR)route from the Tarim Basin(TB)to the Junggar Basin during～420-850 CE provides the opportunity to investigate the relationship between climate change and the spatial evolution of human societies.Here,we use a new high-resolution chironomid-based temperature reconstruction from arid China,combined with hydroclimatic and historical datasets,to assess the possible effects of climate fluctuations on the shift of the ancient SR route.We found that a cooling/drying climate in the TB triggered the SR route shift during～420-600 CE.However,a warming/wetting climate during～600-850 CE did not inhibit this shift,but instead promoted it,because of the favorable climate-induced geopolitical conflicts between the Tubo Kingdom and the Tang Dynasty in the TB.Our findings reveal two distinct ways in which climate change drove the spatial evolution of human civilization,and they demonstrate the flexibility of societal responses to climate change.
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