Advanced 3D ordered electrodes for PEMFC applications: From structural features and fabrication methods to the controllable design of catalyst layers

The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.

Surface-tailored PtPdCu ultrathin nanowires as advanced electrocatalysts for ethanol oxidation and oxygen reduction reaction in direct ethanol fuel cell

The development of advanced electrocatalysts for efficient catalyzing ethanol oxidation reaction(EOR)and oxygen reduction reaction(ORR) is significant for direct ethanol fuel cells(DEFCs).However,in many previous studies,the major difficulties including lower utilization efficiency and weaker anti-CO-poison ability of Pt hamper the practical testing of such DEFCs,Herein,ternary Pt22Pd27C51 ultrathin(~5 nm)NWs are fabricated via a facile surfactant-free strategy.The surface and electronic structures of Pt22Pd27Cu51 NWs are further tailored via acid-etching treatment.The resulted PtPdCu NWs with an optimal atomic Pt/Pd/Cu ratio of 36:41:23 display excellent specific activities towards EOR(4.38 mA/cm^(2))and ORR(1.16 mA/cm^(2)),which are 19.8-and 5.7-folds larger than that of Pt/C,respectively.A singlecell was fabricated using Pt36Pd41Cu23 NWs as electrocatalyst in both anode and cathode with Pt loading of 1.2 mgpt/cm^(2).The power density measured at 80 ℃ is 21.7 mW/cm^(2),which is ~3.9 folds enhancement relative to that fabricated by using Pt/C(2 mgPt/cm^(2)).The enhanced catalytic performance of Pt36Pd41Cu23NWs could be attributed to that synergistic effect between Pt,Pd and Cu enhances CO anti-poisoning ability and promotes the C-C bond cleavage.This work provides a promising strategy for developing efficient electrocatalysts for DEFCs.

Impact of long-term chemical fertilizer and organic amendment to Fusarium root rot of soybean

Soil suppressiveness to Fusarium root rot of soybean had been observed in a black soil field after a long-term fertilization with nitrogen(N)and phosphorus(P)fertilizer combined with pig manure as organic amendment(NPM),rather than that with only nitrogen and phosphorus fertilizer(NP)or no fertilizer(NF).To determine the microbial role on this suppressiveness,fungal and bacterial community characteristics in NPM,NP and NF treatments were investigated by q PCR and DGGE.Compared with the similar bacterial community characteristics among 3 treatments,fungal community,especially Fusarium population size and community composition in NPM treatment were different with those of NP and NF groups.Based on the isolation and pathogenicity test,pathogenic F.oxysporum,F.graminearum,F.verticillioide and F.lateritium absolutely dominated Fusarium community in NF and NP groups.Nonpathogenic F.avenaceum,F.equiseti,F.culmorum,F.redolens,F.solani and F.tricinctum dominated Fusarium community in NPM group.Isolation rate of pathogenic Fusarium in NPM reduced from 100%to 38%in NF.These results suggested that the dominance of soil non-pathogenic Fusarium population induced by organic amendment might play an important role on suppressing Fusarium root rot in the tested field.

Revealing the role of electrode potential micro-environments in single Mn atoms for carbon dioxide and oxygen electrolysis

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention.Herein we construct the well-defined Mn single-atom(MnSA)catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions(CO_(2)RR)and oxygen reduction reactions(ORR).MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90%at-0.9 V for CO_(2)RR and higher H_(2)O_(2)yield from 0.1 to 0.6 V with excellent ORR activity.Density functional theory(DFT)calculations based on constant potential models were performed to study the mechanism of MnSA on CO_(2)RR.The thermodynamic energy barrier of CO_(2)RR is lowest at-0.9 V vs.reversible hydrogen electrode(RHE).Similar DFT calculations on the H_(2)O_(2)yield of ORR showed that the H_(2)O_(2)yield at 0.2 V was higher.This study provides a reasonable explanation for the role of electrode potential micro-environments.

Electronic structures and Mott state of epitaxial TaS_(2) monolayers

Layered material TaS2hosts multiple structural phases and exotic correlated quantum states,including charge density wave(CDW),superconductivity,quantum spin liquid,and Mott insulating state.Here,we synthesized TaS_(2)monolayers in H and T phases using the molecular beam epitaxial(MBE)method and studied their electronic structures via angle-resolved photoemission spectroscopy(ARPES).We found that the H phase TaS_(2)(H-TaS_(2))monolayer is metallic,with an energy band crossing the Fermi level.In contrast,the T phase TaS_(2)(T-TaS_(2))monolayer shows an insulated energy gap at the Fermi level,while the normal calculated band structure implies it should be metallic without any band gap.However,by considering Hubbard interaction potential U,further density functional theory(DFT)calculation suggests that monolayer T-TaS_(2)could be a CDW Mott insulator,and the DFT+U calculation matches well with the ARPES result.More significantly,the temperature-dependent ARPES result indicates that the CDW Mott state in the T-TaS_(2)monolayer is more robust than its bulk counterpart and can persist at room temperature.Our results reveal that the dimensional effect can enhance the CDW Mott state and provide valuable insights for further exploring the exotic properties of monolayer TaS2.

Curcumin modulates oxidative stress to inhibit pyroptosis and improve the inflammatory microenvironment to treat endometriosis

Endometriosis(EM)is a common disease that affects approximately 10%-15%of women of childbearing age.The pathogenesis of EM is unclear,but studies have shown a strong association between EM and inflammation,as well as oxidative stress.^(1) Pyroptosis is also called inflammatory cell death.When pyroptosis occurs,it activates a strong inflammatory response.Pyroptosis is associated with oxidative stress,and Ros act as intermediate triggers to activate pyroptosi.

Complement factor H in molecular regulation of angiogenesis

Angiogenesis,the process of formation of new capillaries from existing blood vessels,is required for multiple physiological and pathological processes.Complement factorH(CFH)is a plasma protein that inhibits the alternative pathway of the complement system.Loss of CFH enhances the alternative pathway and increases complement activation fragments with pro-angiogenic capacity,including complement 3a,complement 5a,and membrane attack complex.CFH protein contains binding sites for C-reactive protein,malondialdehyde,and endothelial heparan sulfates.Dysfunction of CFH prevents its interaction with these molecules and initiates pro-angiogenic events.Mutations in the CFH gene have been found in patients with age-related macular degeneration characterized by choroidal neovascularization.The Cfh-deficient mice show an increase in angiogenesis,which is decreased by administration of recombinant CFH protein.In this review,we summarize the molecular mechanisms of the anti-angiogenic effects of CFH and the regulatory mechanisms of CFH expression.The therapeutic potential of recombinant CFH protein in angiogenesisrelated diseases has also been discussed.

通过调控范霍夫奇点在外延单层VSe_(2)中诱导出巡游铁磁性

处在费米能级处的范霍夫奇点(van Hove singularity)由于具有发散的态密度特征可以诱导出巡游铁磁性.本文在SrTiO_(3)(111)衬底上外延生长单层VSe_(2)薄膜,并通过调控范霍夫奇点诱导出巡游铁磁性.作者通过角分辨光电子能谱技术直接观测到了单层VSe_(2)中的范霍夫奇点能带结构.理论计算表明,当该范霍夫奇异点靠近费米能级时,可通过斯通纳(Stoner)不稳定性产生巡游铁磁性.实验上,作者利用SrTiO_(3)(111)在低温下极大增强的介电常数εr,通过界面电荷转移效应调控范霍夫奇点向费米能级处移动,并通过电输运测量观测到了3.3 K的巡游铁磁性转变.此外,通过改变薄膜层厚和更换衬底的方式,作者可以进一步调控界面电荷转移效果和范霍夫奇点的能量位置,并对巡游铁磁性进行调控.这项研究证明了范霍夫奇点可以成为巡游铁磁性的调控自由度,并拓展了二维磁体在未来电子信息技术的应用潜力.

Mechanism Research of Electroacupuncture Stimulation at Baihui and Zusanli in Cerebral Ischemia-reperfusion Injury Using RNA-Sequencing

Background:Electroacupuncture(EA)therapy,as a combination of electric stimulation and traditional acupunc-ture technology,is currently an important mean for treatment of ischemic stroke and post-stroke rehabilitation in China.Because of its remarkable therapeutic effect,it has been widely used in hospitals and clinic,however,the detailed mechanism remains unclear.Objective:This research aims to comprehensively and systematically elucidate the mechanisms of EA treatment at the acupoints of Zusanli(ST36)and Baihui(GV20)on ischemic stroke.Methods:In this study,EA was performed twice at onset of reperfusion and 20 h after reperfusion following cerebral ischemia-reperfusion(I/R)in middle cerebral artery occlusion(MCAO)rats,and transcriptomic changes of various molecules in ischemic hippocampal neurons of rats in Sham,I/R and EA groups were detected by RNA-Sequencing(RNA-Seq).Results:Thus,we detected 18 significantly different genes related to atherosclerosis(AS),with their functions associated with lipid metabolism,thrombosis,monocytes and vascular smooth muscle cells.And,we detected 10 significantly different genes related to oxidative stress and apoptosis and 10 significantly different genes related to calcium overload and excitatory amino acids release.Also,we detected 19 significantly different genes related to blood-brain barrier(BBB)and 22 significantly different genes related to inflammatory response.Conclusion:In conclusion,EA can play a role in treating ischemic stroke through a variety of mechanisms,affecting atherosclerosis,oxidative stress,apoptosis,calcium overload,excitatory amino acids release,blood-brain barrier(BBB)and inflammatory response.

Thermo-controlled,self-released smart wood tailored by nanotechnology for fast clean-up of highly viscous liquids

Designing highly porous materials is of great importance for liquid separation,water purification,and disinfection,such as spill oil cleaning and recycling,seawater desalting,and oil/water separation.However,a remaining challenge is to produce porous materials with the characteristics of fast absorption,continuous directional transport,and self-release of viscous liquid.Herein,a functional cellulosic composite is reported by the chemical treatment and functionalization of wood resulting in a smart wood that can thermally selfrelease and separate high viscosity oil.The smart wood has a high absorption speed of 1398 mL/(m_(2)·s)(ethylene glycol)and a maximum absorption capacity of 47.2 g/g(chloroform)due to its intrinsic vertical micro/nanoscale channel structure,low tortuosity,and high porosity.Moreover,the switchable wettability is achieved by the surface coating of poly(N-isopropylacrylamide)on the porous wood,which enables the collection and removal of oil from the oil/water mixture.The high viscosity oil can be automatically released due to the passive oil release at room temperature.The release capacity of the smart wood remains above 91%after 15 cyclic tests.We envision that this functional smart wood could be extended to a wide range of applications in smart hydrogels,microfluidics,artificial drug release,and environmental restoration.

Highly conductive dodecaborate/MXene composites for high performance supercapacitors

With the increasingly prominent energy and environmental issues,the supercapacitors,as a highly efficient and clean energy conversion and storage devices,meet the requirements well.However,it is still a challenge to enhance the capacitance and energy density of supercapacitors.A novel and highly conductive dodecaborate/MXene composites have been designed for high performance supercapacitors.The surface charge property of MXene was modified by a simple ultrasonic treatment with ammonium ion,and the dodecaborate ion can be inserted into the inner surface of MXene by electrostatic adsorption.Due to the unique icosahedral cage conjugate structure formed by the B-B bond and the highly delocalized three-dimensionalπbond structure of the electrons,the negative charge is delocalied on the whole dodecaborate ion,which reduces the ability to bind to cations.Therefore,the cations can move easily,and the dodecaborate can act as a“lubricant”for ion diffusion between the MXene layers,which significantly improves the ion transfer rate of supercapacitors.The dodecaborate/MXene composites can achieve an extremely high specific capacitance of 366 F.g^-1 at a scan rate of 2 mV.s^-1,which is more than eight times higher than that of MXene(43 F1-)at the same scan rate.Our finding provides a novel route on the fabrication of the high performance supercapacitors.

Indium doped CsPbI3 films for inorganic perovskite solar cells with efficiency exceeding 17%

In recent years,all-inorganic perovskite materials have set off a research boom owing to features,such as good thermal stability,suitable bandgap,and fascinating optical properties.However,the power conversion efficiency(PCE)and the ambient stability of all-inorganic perovskite solar cells still remain a challenge.Herein,we investigate the effect of the addition of InI3 into CsPbI3 film on the corresponding device.InI3 incorporation could retard the crystallization process and control the growth rate of CsPbI3 polycrystalline films,yielding a high quality film with large grains and few voids.The increment in electrostatic potential and the reduction of carrier recombination enabled the open-circuit voltage of fabricated perovskite solar cell to be increased from 0.89 to 0.99 V.The champion device delivered a power conversion efficiency of 17.09%,which is higher than 14.36%for the reference device.And the InI3-included solar cell without any encapsulation retained 77%of its original efficiency after 860 h aging at room temperature in N2 condition.

rtcisE2F promotes the self-renewal and metastasis of liver tumorinitiating cells via N^(6)-methyladenosine-dependent E2F3/E2F6 mRNA stability

Liver cancer is highly heterogeneous,and the tumor tissue harbors a variety of cell types.Liver tumor initiating cells(TICs)well contribute to tumor heterogeneity and account for tumor initiation and metastasis,but the molecular mechanisms of liver TIC self-renewal are elusive.Here,we identified a functional read-through rt-circRNA,termed rtcisE2F,that is highly expressed in liver cancer and liver TICs.rtcisE2F plays essential roles in the self-renewal and activities of liver TICs.rtcisE2F targets E2F6 and E2F3 mRNAs,attenuates mRNA turnover,and increases E2F6/E2F3 expression.Mechanistically,rtcisE2F functions as a scaffold of N^(6)-methyladenosine(m^(6)A)reader IGF2BP2 and E2F6/E2F3 mRNA.rtcisE2F promotes the association of E2F6/E2F3 mRNAs with IGF2BP2,and inhibits their association with another m^(6)A reader,YTHDF2.IGF2BP2 inhibits E2F6/E2F3 mRNA decay,whereas YTHDF2 promotes E2F6/E2F3 mRNA decay.By switching m^(6)A readers,rtcisE2F enhances E2F6/E2F3 mRNA stability.E2F6 and E2F3 are both required for liver TIC self-renewal and Wnt/β-catenin activation,and inhibition of these pathways is a potential strategy for preventing liver tumorigenesis and metastasis.In conclusion,the rtcisE2F-IGF2BP2/YTHDF2-E2F6/E2F3-Wnt/β-catenin axis drives liver TIC self-renewal and initiates liver tumorigenesis and metastasis,and may provide a strategy to eliminate liver TICs.

Ultrathin nanoporous metal electrodes facilitate high proton conduction for low-Pt PEMFCs

Design of catalyst layers(CLs)with high proton conductivity in membrane electrode assemblies(MEAs)is an important issue for proton exchange membrane fuel cells(PEMFCs).Herein,an ultrathin catalyst layer was constructed based on Pt-decorated nanoporous gold(NPG-Pt)with sub-Debye-length thickness for proton transfer.In the absence of ionomer incorporation in the CLs,these integrated carbon-free electrodes can deliver maximum mass-specific power density of 198.21 and 25.91 kW·gPt^(-1) when serving individually as the anode and cathode,at a Pt loading of 5.6 and 22.0 pg·cm^(-2),respectively,comparable to the best reported nano-catalysts for PEMFCs.In-depth quantitative experimental measurements and finite-element analyses indicate that improved proton conduction plays a critical role in activation,ohmic and mass transfer polarizations.

Transdermal delivery of interleukin-12 gene targeting dendritic cells enhances the anti-tumour effect of programmed cell death protein 1 monoclonal antibody

Recent studies have suggested that the anti-tumour effect of the programmed cell death protein 1 monoclonal antibody(aPD-1)depends on the expression of interleukin-12(IL-12)by dendritic cells(DCs).Since DCs are abundant in skin tissues,transdermal delivery of IL-12 targeting DCs may significantly improve the anti-tumour effect of aPD-1.In this study,a novel mannosylated chitosan(MC)-modified ethosome(Eth-MC)was obtained through electrostatic adsorption.The Eth-MC loaded with plasmid containing the IL-12 gene(pIL-12@Eth-MC)stimulated DCs to express mature-related molecular markers such as CD86,CD80,and major histocompatibility complex-II in a targeted manner.The pIL-12@Eth-MC was then mixed with polyvinyl pyrrolidone solution to make microspheres using the electrospray technique,and sprayed onto the surface of electrospun silk fibroin-polyvinyl alcohol nanofibres to obtain a PVP-pIL-12@Eth-MC/silk fibroin-polyvinyl alcohol composite nanofibrous patch(termed a transcutaneous immunization(TCI)patch).The TCI patch showed a good performance on transdermal drug release.Animal experiments on melanoma-bearing mice showed that topical application of the TCI patches promoted the expression of IL-12 and inhibited the growth of tumour.Furthermore,combined application of the TCI patch and aPD-1 showed a stronger anti-tumour effect than aPD-1 monotherapy.The combination therapy significantly promoted the expression of IL-12,interferon-γand tumour necrosis factor-α,the infiltration of CD4+and CD8+T cells into tumour tissues,and thus promoted the apoptosis of tumour cells.The present study provides a convenient and non-invasive strategy for improving the efficacy of immune checkpoint inhibitor therapy.This study was approved by the Institutional Animal Care and Use Committee at Donghua University(approval No.DHUEC-NSFC-2020-11)on March 31,2020.