Elucidating the structure-activity relationship of Cu-Ag bimetallic catalysts for electrochemical CO_(2) reduction

Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.

Component Analysis and Calculation for Social Benefits of UHV Assessment

With the rapid development of the UHV power grid, evaluation of the economic and social benefits of the UHV power grid is conducive to guiding the planning and construction of UHV power grid. At present economic benefit evaluation system of the UHV power grid is driving to maturity stage on the whole at home and abroad, but it invariably tends to regard social benefits as part of economic benefits, without evaluating social benefit separately. The social benefit evaluation model of UHV power grid is built in case of sufficient investigation. The differentials between social benefit and social cost are calculated respectively by three kinds of solutions according to the constructed social cost evaluation index system and social benefits evaluation index system, conclusion that UHV power grid transmission has better social benefits can be reached by contrastively analyzing the social three kinds of solutions corresponding to benefits. At last, the evaluation model and method are verified and analyzed through the analysis of engineering projects.

Cell Membrane Coating Technology:A Promising Strategy for Biomedical Applications

Cell membrane coating technology is an approach to the biomimetic replication of cell membrane properties,and is an active area of ongoing research readily applicable to nanoscale biomedicine.Nanoparticles(NPs)coated with cell membranes offer an opportunity to unite natural cell membrane properties with those of the artificial inner core material.The coated NPs not only increase their biocompatibility but also achieve effective and extended circulation in vivo,allowing for the execution of targeted functions.Although cell membrane-coated NPs offer clear advantages,much work remains before they can be applied in clinical practice.In this review,we first provide a comprehensive overview of the theory of cell membrane coating technology,followed by a summary of the existing preparation and characterization techniques.Next,we focus on the functions and applications of various cell membrane types.In addition,we collate model drugs used in cell membrane coating technology,and review the patent applications related to this technology from the past 10 years.Finally,we survey future challenges and trends pertaining to this technology in an effort to provide a comprehensive overview of the future development of cell membrane coating technology.

Copper-indium hydroxides derived electrocatalysts with tunable compositions for electrochemical CO_(2) reduction

Bimetallic Cu-In hybrid electrocatalysts are promising noble metal-free catalysts for selective electrochemical CO_(2) reduction reaction(ECO_(2) RR).Most reports show Cu-In catalysts are selective towards CO evolutio n.However,few show similarly high selectivity towards formate.Herein we fabricated composition tunable Cu-In hydroxides(Cu_xIn_y-OH) by the hydrothermal method and studied their composition effect on electrochemical CO_(2) reduction in detail. We found that the selectivity of CO_(2) reduction products shifted from CO to formate when the content of In increased in the Cu_xIn_y-OH electrocatalysts.The Cu rich electrocatalyst mostly produced CO,which could achieve a Faradaic efficiency(FE) to 75.8% at-0.59 V vs.RHE(Cu_(76)In_(24)based electrocatalysts).In comparison,the In rich electrocatalysts selectively produced formate,which possessed the FE of formate up to 85% at-1.01 V vs.RHE.Our work systematically illustrates the composition effect on hybrid catalysts,and provides insights into the design of highly selective catalysts for ECO_(2) RR.

The removal of inevitable NOx species in catalysts and the selection of appropriate membrane for measuring electrocatalytic ammonia synthesis accurately

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising alternative to the Haber−Bosch process.However,due to the extremely low ammonia yield and easily accessible extraneous contamination in the laboratory,NRR study always suffers from fluctuation and variability.Finding and eliminating all kinds of possible extraneous contamination is crucial to evaluate the performance of electrocatalytic ammonia synthesis accurately.In this work,we systematically explored two factors that affect NRR results but are easy to be ignored:the selection of membrane for NRR and the unconscious N-source in NRR catalysts.After series of experiments,we proposed a low-cost and almost pollution-free Celgard 3501 membrane as the separator for NRR to avoid the adsorption and release of ammonia by the membrane.In addition,we proposed a pre-reduction strategy to remove residual or adsorbed NOx contaminants in catalysts.These two solutions will help the community to evaluate the NRR activity more accurately.

Double interface modification promotes efficient Sb2Se3 solar cell by tailoring band alignment and light harvest

The band alignment at the front interfaces is crucial for the performance of Sb_(2)Se_(3) solar cell with superstrate configuration.Herein,a Sn O_(2)/Ti O_(2) thin film,demonstrated beneficial for carrier transport in Sb_(2)Se_(3) device by the first-principle calculation and experiment,is proposed to reduce the parasitic absorption caused by CdS and optimize the band alignment of Sb_(2)Se_(3) solar cell.Thanks to the desirable transmittance of SnO_(2)/TiO_(2) layer,the Sb_(2)Se_(3) solar cell with SnO_(2)/TiO_(2)/(CdS-38 nm) electron transport layer performances better than (CdS-70 nm)/Sb_(2)Se_(3) solar cell.The optimized band alignment,the reduced interface defects and the decreased current leakage of Sb_(2)Se_(3) solar cell enable the short-circuit current density,fill factor,open-circuit voltage and efficiency of the Sb_(2)Se_(3) solar cell increase by 26.7%,112%,33.1%and 250%respectively when comparing with TiO_(2)/Sb_(2)Se_(3) solar cell without modification.Finally,an easily prepared Sn O_(2)/Ti O_(2)/CdS ETL is successfully applied on Sb_(2)Se_(3) solar cell by the first time and contributes to the best efficiency of 7.0%in this work,which is remarkable for Sb_(2)Se_(3) solar cells free of hole transporting materials and toxic CdCl_(2) treatment.This work is expected to provide a valuable reference for future ETL design and band alignment for Sb_(2)Se_(3) solar cell and other optoelectronic devices.

UV light absorbers executing synergistic effects of passivating defects and improving photostability for efficient perovskite photovoltaics

Metal halide perovskite-based solar cells(PSCs) have rapidly-increased power conversion efficiency(PCE)exceeding 25% but poor stability especially under ultraviolet(UV) light. Meanwhile, non-radiative recombination caused by diverse defects in perovskite absorbers and related interfaces is one of the major factors confining further development of PSCs. In this study, we systematically investigate the role of 2-(2-hydroxy-5-methylphenyl)benzotriazole(UVP) additive in perovskite layers. By adjusting the amount of doped UVP, the quality of perovskite absorbers is significantly improved with enlarged grains, longer lifetime and diffusion length of charge carriers. Furthermore, UVP not only reduces defects for less nonradiative recombination, but also matches energy level alignment for efficient interfacial charge extraction. X-ray photoelectron spectroscopy confirms that N-donor of UVP molecule coordinates with undercoordinated Pb^(2+) on the surface. Interestingly, UVP incorporated in PbI_(2) protects the perovskite by absorbing UV through the opening and closing of the chelating ring. Eventually, the UVP treated PSCs obtain a champion PCE of 22.46% with remarkably enhanced UV stability, retaining over 90% of initial PCE after 60 m W/cm^(2) strong UV irradiation for 9 h while the control maintaining only 74%. These results demonstrate a promising strategy fabricating passivated and UV-resistant perovskite materials simultaneously for efficient and stable perovskite photovoltaics.

Effects of guanidinium cations on structural,optoelectronic and photovoltaic properties of perovskites

Guanidinium(GA)cations are intentionally introduced in MAPbI_(3) perovskite by considering its potential capability of stabilizing the material through plenty of hydrogen bonds and mitigating hysteresis because of the zero dipole moment.The configurations of GA cation in film and its effects on structural,optoelectronic and photovoltaic properties of perovskite have been comprehensively studied by systematically modulating the GA ratio.It has been demonstrated that moderate GA cations can effectively passivate the defect surrounding perovskite grains,yielding an enhanced efficiency as high as~19,2%in a p-i-n type planar solar cells with the GA ratio of 15%.Further increasing the GA ratio deteriorates device performance,as extra GA cations hinder grain growth and thus reduce the grain size,which facilitates the defect generation around the enhanced interface.Moreover,a new two-dimensional(2 D)layered perovskite phase that features alternating GA and MA cations in the interlayer space(ACI)appears ultimately,while the ACI phase typically suffers from slow charge transportation across the parallel PbI2 octahedral layers separated by large A-site cations.

The pitfalls in electrocatalytic nitrogen reduction for ammonia synthesis

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(EC-NRR)has gained momentum in recent years fueled by its potential to operate at ambient conditions,unlike the highly energyintensive yet long-standing Haber-Bosch process.However,the large disparity of the yields and Faradic efficiencies reported for EC-NRR raises serious concerns about the reliability of the experimental results.In this perspective,we elaborate on the potential sources of error when assessing EC-NRR and update the testing protocols to circumvent them,and more importantly,we pose a general call for consensus on ammonia production analysis and reporting to lay the solid foundations that this burgeoning field requires to thrive.

Co-electrolysis of ethylene glycol and carbon dioxide for formate synthesis

Co-electrolysis of waste plastics and carbon dioxide(CO_(2)) into value-added chemicals or fuels is a promising pathway for a sustainable society, but efficient and selective conversion remains a challenge. Herein, a gold-mediated nickel hydroxide(Au/Ni(OH)_(2)) is developed to oxidize waste plastic-derived ethylene glycol(EG) into formate. In-situ electrochemical experiments and theoretical results reveal that the introduction of Au favors the redox properties and EG adsorption behavior of Ni(OH)_(2). The Au/Ni(OH)_(2) catalyst shows an excellent formate selectivity of >90% at high current densities of above 100 m A cm^(-2). When coupled with sputtered bismuth(Bi) cathode for CO_(2) reduction, a high formate Faradic efficiency(FE) of 188.2% at 200 m A cm^(-2)and a good formate productivity of 7.33 mmol m^(-2)s^(-1)at 10 A are obtained in a flow cell and a zero-gap membrane electrode assembly(MEA) cell, respectively. This work demonstrates a promising strategy to convert waste plastics and CO_(2) into valuable products.

Healing the defects in CsPbI_(3)solar cells by CsPbBr_(3)quantum dots

Cesium lead iodide(CsPbI_(3))is a promising photo-absorber for perovskite photovoltaics due to its high thermal stability and relatively small bandgap.However,there are many defects in solution processed polycrystalline CsPbI_(3)films especially at the grain boundaries(GBs),which limit the power conversion efficiency(PCE)of CsPbI_(3)solar cells.In this work,we introduced CsPbBr_(3)quantum dots(QDs)on top of the CsPbI_(3)film to passivate the defects.As CsPbBr_(3)QDs have a small size and a similar crystal structure as the CsPbI_(3),they are excellent modifiers to fill in the GBs and heal the defects.Moreover,we find there is an anion exchange reaction between the CsPbBr_(3)QDs and CsPbI_(3)films,which is evidenced by photoluminescence spectra and grazing incidence X-ray diffraction patterns.The QDs treated films show enhanced carrier lifetime and reduced defect density.Additionally,the ligands on CsPbBr_(3)QDs increase the hydrophobicity of the films.As a result,the QDs treated CsPbI_(3)solar cells prepared at high temperature obtain PCEs exceeding 16%with high stability.

Regulated CO adsorption by the electrode with OH^(-) repulsive property for enhancing C–C coupling

Electrochemical CO_(2) reduction driven by renewable electricity is one of the promising strategies to store sus-tainable energy as fuels.However,the selectivity of value-added multi-carbon products remains poor for further application of this process.Here,we regulate CO adsorption by forming a Nafion layer on the copper(Cu)electrode that is repulsive to OH^(-),contributing to enhanced selectivity of CO_(2) reduction to C_(2) products with the suppression of C 1 products.The operando Raman spectroscopy indicates that the local OH^(-)would adsorb on part of active sites and decrease the adsorption of CO.Therefore,the electrode with repulsive to OH^(-)can adjust the concentration of OH^(-),leading to the increased adsorption of CO and enhanced C–C coupling.This work shows that electrode design could be an effective strategy for improving the selectivity of CO_(2) reduction to multi-carbon products.

A coupled electrochemical system for CO_(2)capture,conversion and product purification

The efficient utilization of carbon dioxide(CO_(2))as a resource,comprises three key processes:CO_(2)capture,catalytic conversion and product purification.Using the renewable electricity to drive these processes provides a promising pathway for mitigating the ever-increasing atmospheric CO_(2)concentration whilst simultaneously addressing the growing energy demand.Although each of the three individual processes has been extensively investigated during the past decade,the rapid and economically viable reduction of CO_(2)emissions still calls for the development of an integrated electrochemical system driven by the renewable electricity to achieve carbon neutrality.Herein,we report a systematic protocol to bridge the three individual CO_(2)utilization processes into one coupled electrochemical system:a bipolar membrane electrodialysis(BPMED)cell generating alkaline and acidic solutions for the capture and recovery of CO_(2),a flow cell with an Ag gas diffusion electrode(GDE)for the selective electrocatalytic reduction of the recovered CO_(2),and an alkaline solution container for the purification of the gaseous products and recycle of the unreacted CO_(2).Consequently,the coupled electrochemical system successfully captured CO_(2)from the simulated flue gas and converted it into a pure syngas stream.

CsPb(I_(x)Br_(1-x))_(3) solar cells

Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.

A water-stable organolead iodide material for overall photocatalytic CO_(2) reduction

The utilization of perovskites as photocatalysts to convert CO_(2) into fuels and chemicals has received wide attention recently.However,their instability in water hinders their long-term application for overall photocatalytic CO_(2) reduction.Herein,we integrate the water-stable perovskite-like organolead iodide crystalline material[Pb8I8(H2O)3]8+[-O2C(CH2)4CO_(2)-]4(TJU-16)with Au co-catalyst for photocatalytic CO_(2) reduction in aqueous solution without sacrificial reagent.Under the AM 1.5 G simulated illumination,the TJU-16 with 0.19 wt.‰ Au co-catalyst steadily generated electrons for CO_(2) reduction reaction,which was 2.2 times of pure TJU-16.The Au0.19/TJU-16 catalyzed CO_(2) reduction at a rate of 84.2μmol·g-1·h-1,and achieved a solar-to-fuel(STF)conversion efficiency of 0.034%.Our work will motivate the rational design of water-stable perovskite-like materials for photocatalytic applications.

Rational Design of Thermosensitive Hydrogel to Deliver Nanocrystals with Intranasal Administration for Brain Targeting in Parkinson’s Disease

Mitochondrial dysfunction is commonly detected in individuals suffering from Parkinson’s disease(PD),presenting within the form of excessive reactive oxygen species(ROS)generation as well as energy metabolism.Overcoming this dysfunction within brain tissues is an effective approach to treat PD,while unluckily,the blood-brain barrier(BBB)substantially impedes intracerebral drug delivery.In an effort to improve the delivery of efficacious therapeutic drugs to the brain,a drug delivery platform hydrogel(MAG-NCs@Gel)was designed by complexing magnolol(MAG)-nanocrystals(MAG-NCs)into the noninvasive thermosensitive poly(Nisopropylacrylamide)(PNIPAM)with self-gelation.The as-prepared MAG-NCs@Gel exhibited obvious improvements in drug solubility,the duration of residence with the nasal cavity,and the efficiency of brain targeting,respectively.Above all,continuous intranasal MAG-NCs@Gel delivery enabled MAG to cross the BBB and enter dopaminergic neurons,thereby effectively alleviating the symptoms of MPTP-induced PD.Taking advantage of the lower critical solution temperature(LCST)behavior of this delivery platform increases its viscoelasticity in nasal cavity,thus improving the efficiency of MAG-NCs transit across the BBB.As such,MAG-NCs@Gel represented an effective delivery platform capable of normalizing ROS and adenosine triphosphate(ATP)in the mitochondria of dopaminergic neurons,consequently reversing the mitochondrial dysfunction and enhancing the behavioral skills of PD mice without adversely affecting normal tissues.

Chemically tailored molecular surface modifiers for efficient and stable perovskite photovoltaics

Perovskite solar cells(PSCs)have attracted intense attention based on their high power conversion efficiency and low production cost.However,due to the polycrystalline nature and the intrinsic hydrophilicity of the metal halide perovskite moieties,the photovoltaic performance of PSCs is largely limited by defects within the polycrystalline perovskites and the sensitivity to moisture.In this perspective,we focus on the chemically tailored interface materials to passivate the defects and improve the moisture stability of PSCs.First,we provide a brief overview of various molecular interface modifiers.Thereafter we provide examples from our recent work on organic ammonium halide‐based passivation materials as representatives to illustrate the design strategies and the modification effects.In the end,we shed light on the future devel-opment of organic ammonium halides for applications in PSCs.

Ultrasmall Coordination Polymers for Alleviating ROS-Mediated Inflammatory and Realizing Neuroprotection against Parkinson's Disease

Parkinson's disease(PD)is the second most common neurodegenerative disease globally,and there is currently no effective treatment for this condition.Excessive accumulation of reactive oxygen species(ROs)and neuroinflammation are major contributors to PD pathogenesis.Herein,ultrasmall nanoscale coordination polymers(NCPs)coordinated by ferric ions and natural product curcumin(Cur)were exploited,showing efficient neuroprotection by scavenging excessive radicals and suppressing neuroinflammation.In a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse PD model,such ultrasmall Fe-Cur NCPs with prolonged blood circulation and BBB traversing capability could effectively alleviate oxidative stress,mitochondrial dysfunction,and inflammatory condition in the midbrain and striatum to reduce PD symptoms.Thus,this study puts forth a unique type of therapeutics-based NCPs that could be used for safe and efficient treatment of PD with potential in clinical translation.

Rational Design of Thermosensitive Hydrogel to Deliver Nanocrystals with Intranasal Administration for Brain Targeting in Parkinson’s Disease

Mitochondrial dysfunction is commonly detected in individuals suffering from Parkinson’s disease(PD),presenting within the form of excessive reactive oxygen species(ROS)generation as well as energy metabolism.Overcoming this dysfunction within brain tissues is an effective approach to treat PD,while unluckily,the blood-brain barrier(BBB)substantially impedes intracerebral drug delivery.In an effort to improve the delivery of efficacious therapeutic drugs to the brain,a drug delivery platform hydrogel(MAG-NCs@Gel)was designed by complexing magnolol(MAG)-nanocrystals(MAG-NCs)into the noninvasive thermosensitive poly(Nisopropylacrylamide)(PNIPAM)with self-gelation.The as-prepared MAG-NCs@Gel exhibited obvious improvements in drug solubility,the duration of residence with the nasal cavity,and the efficiency of brain targeting,respectively.Above all,continuous intranasal MAG-NCs@Gel delivery enabled MAG to cross the BBB and enter dopaminergic neurons,thereby effectively alleviating the symptoms of MPTP-induced PD.Taking advantage of the lower critical solution temperature(LCST)behavior of this delivery platform increases its viscoelasticity in nasal cavity,thus improving the efficiency of MAG-NCs transit across the BBB.As such,MAG-NCs@Gel represented an effective delivery platform capable of normalizing ROS and adenosine triphosphate(ATP)in the mitochondria of dopaminergic neurons,consequently reversing the mitochondrial dysfunction and enhancing the behavioral skills of PD mice without adversely affecting normal tissues.