Active-site and interface engineering of cathode materials for aqueous Zn–gas batteries

Aqueous rechargeable Zn–gas batteries are regarded as promising energy storage and conversion devices due to their high safety and inherent environmental friendliness.However,the energy efficiency and power density of Zn–gas batteries are restricted by the kinetically sluggish cathode reactions,such as oxygen evolution reaction(OER)during charging and oxygen reduction reaction(ORR)/carbon dioxide reduction reaction(CO_(2)RR)/nitrogen reduction reaction(NRR)/nitric oxide reduction reaction(NORR)during discharge.In this review,battery configurations and fundamental reactions in Zn–gas batteries are first introduced,including Zn–air,Zn-CO_(2),Zn-N_(2),and Zn-NO batteries.Afterward,recent advances in active site engineering for enhancing the intrinsic catalytic activities of cathode catalysts are summarized.Subsequently,the structure and surface regulation strategies of cathode materials for optimizing the three-phase interface and improving the performance of Zn–gas batteries are discussed.Finally,some personal perspectives for the future development of Zn–gas batteries are presented.

Sol-gel-based porous Ti-doped tungsten oxide films for high-performance dual-band electrochromic smart windows

Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.

Au core-PtAu alloy shell nanowires for formic acid electrolysis

Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au core-Pt Au alloy shell nanowires(Au@PtxAu UFNWs).Among them,Au@Pt_(0.077) Au UFNWs exhibit the best performance for formic acid oxidation reaction(FAOR)and hydrogen evolution reaction(HER),which only require applied potentials of 0.29 V and-22.6 m V to achieve a current density of 10 m A cm^(-2),respectively.The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 m A cm^(-2) current density.Density functional theory(DFT)calculations reveal that the Au-riched Pt Au alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt_(0.077) Au UFNWs.This work provides meaningful insights into the electrochemical H_(2) production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.

Reversible Zn^(2+) Insertion in Tungsten Ion-Activated Titanium Dioxide Nanocrystals for Electrochromic Windows

Zinc-anode-based electrochromic devices(ZECDs) are emerging as the next-generation energy-e cient transparent electronics. We report anatase W-doped TiO_(2) nanocrystals(NCs) as a Zn^(2+) active electrochromic material. It demonstrates that the W doping in TiO_(2) highly reduces the Zn^(2+) intercalation energy,thus triggering the electrochromism. The prototype ZECDs based on W-doped TiO_(2) NCs deliver a high optical modulation(66% at 550 nm),fast spectral response times(9/2.7 s at 550 nm for coloration/bleaching),and good electrochemical stability(8.2% optical modulation loss after 1000 cycles).

Progress in Nanocellulose Preparation and Application

Nanocellulose is a biodegradable, renewable, nonmeltable polymeric material that is insoluble in most solvents due to hydrogen bonding and crystallinity. Nanocellulose has attracted considerable attention in recent decades owing to its environmental friendliness, wide availability, good biocompatibility, high crystallinity, and high Young's modulus. This review presents the recent achievements in preparation and applications of nanocellulose, including a discussion of the advantages and disadvantages of various preparation methods and a summary of the applications of nanocellulose in composite materials research. Finally, we examine the mounting evidence of more widespread potential applications of nanocellulose.

HEHEHP从离子吸附型稀土精矿中回收钪

2-乙基己基磷酸单(2-乙基己基)酯(HEHEHP)对4 mol/L HCl稀土溶液中的钪具有极高的选择性,其分离系数βSc/REEs超过了8000,且在20 min内达到萃取平衡。萃取后的钪在363 K下,利用5 mol/L NaOH作为洗脱剂,洗脱率达到92.1%。利用斜率法、饱和萃取法、红外光谱分析和核磁共振分析阐明了萃取机理。结果表明,HEHEHP在4 mol/L HCl溶液中萃取Sc主要是以P—O—H中的H与Sc的离子交换过程,以及P=O与Sc的配位过程为主导,且6个萃取剂分子作为二聚体参与萃取。最后,提出了从离子吸附型稀土精矿中回收钪的工艺流程,并在实验室进行了验证。

Boosting electroluminescence performance of all solution processed In P based quantum dot light emitting diodes using bilayered inorganic hole injection layers

The development of high-performance In P-based quantum dot light-emitting diodes(QLEDs)has become the current trend in ecofriendly display and lighting technology.However,compared with Cd-based QLEDs that have already been devoted to industry,the efficiency and stability of In P-based QLEDs still face great challenges.In this work,colloidal Ni Oxand Mg-doped Ni Oxnanocrystals were used to prepare a bilayered hole injection layer(HIL)to replace the classical polystyrene sulfonate(PEDOT:PSS)HIL to construct high-performance In Pbased QLEDs.Compared with QLEDs with a single HIL of PEDOT:PSS,the bilayered HIL enables the external quantum efficiencies of the QLEDs to increase from 7.6%to 11.2%,and the T_(95)lifetime(time that the device brightness decreases to 95%of its initial value)under a high brightness of 1000 cd m^(-2)to prolong about 7 times.The improved performance of QLEDs is attributed to the bilayered HIL reducing the mismatched potential barrier of hole injection,narrows the potential barrier difference of indium tin oxide(ITO)/hole transport layer interface to promote carrier balance injection,and realizes high-efficiency radiative recombination.The experimental results indicate that the use of bilayered HILs with p-type Ni Oxmight be an efficient method for fabricating high-performance In P-based QLEDs.

双功能Nb-N-C原子分散催化剂用于水系锌-空气电池驱动CO_(2)还原

设计廉价和高效的双功能催化剂应用于CO_(2)还原和O_(2)还原反应(CO_(2)RR和ORR)是实现碳中和的理想选择.因此,本文研制出铌原子分散固定在氮掺杂有序介孔碳(Nb-N-C)上的双功能CO_(2)RR和ORR催化剂用于锌-空气电池(ZAB)自驱动CO_(2)RR.得益于高铌原子利用率和有序介孔结构,Nb-N-C催化剂展现出高达90%的CO法拉第效率,ORR的半波电位活性为0.84 V,ZAB的峰值功率活性为115.6 mW cm-2.此外,采用两个串联的ZABs单元作为自供能CO_(2)RR系统的电源,能够连续将C O_(2)转化为C O.该自供能系统前10小时的C O平均产率为3.75μmol h-1mg-1cat.理论计算表明,铌原子分散固定在氮掺杂的碳上形成Nb–N配位键,从而有效地降低CO_(2)RR的决速中间体*COOH和ORR的决速中间体*O的生成能垒.

高熵合金在水电解中的研究进展、基础与挑战

氢能作为一种清洁能源,已成为全球能源战略的重要组成部分,也是实现全球“碳中和”的必要途径之一.在可再生电力的驱动下,水电解法有望成为实现“零碳”排放的一种理想的长期制氢方法.与传统合金相比,高熵合金由于其独特的结构特征,包括占位无序和晶格有序,可提供更多的催化活性位点.它们在水解催化剂领域具有广泛的应用前景.本文综述了电解水的机理、水解过程中高熵合金的催化原理,以及高熵合金作为电解水催化剂的最新研究进展.总结了新型高熵合金设计方面存在的难点及其应用潜力,重点讨论了高熵合金在水解催化过程中表面形态和催化活性之间的联系.最后归纳了高熵合金的组成调控及其在水电解等新兴领域的可能应用前景.

Carrier recombination suppression and transport enhancement enable high-performance self-powered broadband Sb_(2)Se_(3) photodetectors

Antimony selenide(Sb_(2)Se_(3))is a promising candidate for photodetector applications boasting unique material benefits and remarkable optoelectronic properties.Achieving high-performance self-powered Sb_(2)Se_(3)photodetector through a synergistic regulation of absorber layer and heterojunction interface demonstrates great potential and needs essential investigation.In this study,an effective two-step thermodynamic/kinetic deposition technique containing sputtered and selenized Sb precursor is implemented to induce self-assembled growth of Sb_(2)Se_(3)light absorbing thin film with large crystal grains and desirable[hk1]orientation,presenting considerable thin-film photodetector performance.Furthermore,aluminum(Al^(3+))cation dopant is introduced to modify the optoelectronic properties of CdS buffer layer,and further optimize the Sb_(2)Se_(3)/CdS(Al)heterojunction interface quality.Thanks to the suppressed carrier recombination and enhanced carrier transport kinetics,the champion Mo/Sb_(2)Se_(3)/CdS(Al)/ITO/Ag photodetector exhibits self-powered and broadband characteristics,accompanied by simultaneously high responsivity of 0.9 A W^(-1)(at 11 nW cm^(-2)),linear dynamic range of 120 dB,impressive ON/OFF switching ratio over 10^(6)and signal-to-noise ratio of 10^(9),record total noise determined realistic detectivity of 4.78×10^(12)Jones,and ultra-fast response speed with rise/decay time of 24/75 ns,representing the top level for Sb_(2)Se_(3)-based photodetectors.This intriguing work opens up an avenue for its selfpowered broadband photodetector applications.

Bifunctional hierarchical NiCoP@FeNi LDH nanosheet array electrocatalyst for industrial-scale high-current-density water splitting

Aiming to design and prepare non-noble metal electrocatalysts for hydrogen production at high current density(HCD),NiCoP@FeNi LDH hierarchical nanosheets were deposited on nickel foam progressively us-ing a hydrothermal-phosphorization-electrodeposition process.For hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),NiCoP@FeNi LDH/NF requires only 195 and 230 mV overpotentials to reach 1000 mA cm−2,respectively.For overall water splitting,only 1.70 V is required at 1000 mA cm−2.This is the largest value for non-noble metal-based electrocatalysts reported so far at HCD.The hierarchi-cal structure exhibits good electron transport capability and the porous-macroporous structure enhances the gas release rate,resulting in enhanced hydrogen production at HCD.Especially,the synergistic effect of NiCoP and FeNi LDH contributes to the adsorption-desorption equilibrium of intermediate radicals dur-ing the reaction process and ultimately enhances the catalytic activity.This work provides useful direction for industrial-scale hydrogen production applications at HCD.

Clustering-triggered Emission of Cellulose and Its Derivatives

In recent years, nonconventional luminogens free of aromatic groups have attracted extensive attention due to their academic importance and promising wide applications. Whilst previous studies generally focused on fluorescence from aliphatic amine or carbonylcontaining systems, less attention has been paid to room temperature phosphorescence(RTP) and the systems with predominant oxygen functionalities. In this work, photophysical properties of the polyhydroxy polymers, including microcrystalline cellulose(MCC), 2-hydroxyethyl cellulose(HEC), hydroxypropyl cellulose(HPC), and cellulose acetate(CA), were studied and compared. While MCC,HEC, and HPC solids showed bright emission alongside distinct RTP, CA demonstrated relatively low intensity of solid emission without noticeable RTP. Their emissions were explained in terms of the clustering-triggered emission(CTE) mechanism and conformation rigidification. Additionally, on account of its intrinsic emission, concentrated HEC aqueous solution could be used as the probe for the detection of 2,4,6-trinitrophenol(TNP).

Boosting triplet self-trapped exciton emission in Te(IV)-doped Cs_(2)SnCl_(6) perovskite variants

Perovskite variants have attracted wide interest because of the lead-free nature and strong self-trapped exciton (STE) emission. Divalent Sn(II) in CsSnX3 perovskites is easily oxidized to tetravalent Sn(IV), and the resulted Cs2SnCl6 vacancy-ordered perovskite variant exhibits poor photoluminescence property although it has a direct band gap. Controllable doping is an effective strategy to regulate the optical properties of Cs2SnX6. Herein, combining the first principles calculation and spectral analysis, we attempted to understand the luminescence mechanism of Te4+-doped Cs2SnCl6 lead-free perovskite variants. The chemical potential and defect formation energy are calculated to confirm theoretically the feasible substitutability of tetravalent Te4+ ions in Cs2SnCl6 lattices for the Sn-site. Through analysis of the absorption, emission/excitation, and time-resolved photoluminescence (PL) spectroscopy, the intense green-yellow emission in Te4+:Cs2SnCl6 was considered to originate from the triplet Te(IV) ion 3P1→1S0 STE recombination. Temperature-dependent PL spectra demonstrated the strong electron-phonon coupling that inducing an evident lattice distortion to produce STEs. We further calculated the electronic band structure and molecular orbital levels to reveal the underlying photophysical process. These results will shed light on the doping modulated luminescence properties in stable lead-free Cs2MX6 vacancy-ordered perovskite variants and be helpful to understand the optical properties and physical processes of doped perovskite variants.

MoC nanocrystals confined in N-doped carbon nanosheets toward highly selective electrocatalytic nitric oxide reduction to ammonia

Electrochemical nitric oxide reduction reaction(NORR)to produce ammonia(NH3)under ambient conditions is a promising alternative to the energy and carbon-intensive Haber–Bosch approach,but its performance is still improved.Herein,molybdenum carbides(MoC)nanocrystals confined by nitrogen-doped carbon nanosheets are first designed as an efficient and durable electrocatalyst for catalyzing the reduction of NO to NH3 with maximal Faradaic efficiency of 89%±2%and a yield rate of 1,350±15μg·h^(−1)·cm^(−2) at the applied potential of−0.8 V vs.reversible hydrogen electrode(RHE)as well as high stable activity with negligible current density and NH3 yield rate decays over a 30 h continue the test.Moreover,as a proof-of-concept of Zn–NO battery,it achieves a peak power density of 1.8 mW·cm^(−2) and a large NH3 yield rate of 782±10μg·h^(−1)·cm^(−2),which are comparable to the best-reported results.Theoretical calculations reveal that the MoC(111)has a strong electronic interaction with NO molecules and thus lowering the energy barrier of the potential-determining step and suppressing hydrogen evolution kinetics.This work suggests that Mo-based materials are a powerful platform providing great opportunities to explore highly selective and active catalysts for NH3 production.

部分磷化双金属中心集成制备高性能三功能催化剂用于制氢和柔性锌-空气电池

开发高效且性能稳定的氧析出(OER)、氧还原(ORR)和氢析出(HER)三功能催化剂是制备能源存储与转换设备的关键.本文使用一步磷化法,在氮磷共掺杂碳基上制备了Fe Co金属合金/磷化物催化剂(Fe Co-P/PNC).该催化剂显示了良好的ORR性能,展现了0.86 V (vs.RHE,相对于可逆氢电极)的半波电位;在OER和HER反应中,催化剂在10 m A cm^(-2)的电流密度下的过电位分别为350和158 m V.密度泛函理论计算表明,磷在Fe Co磷化物和碳基体中皆起主导作用,使得该催化剂同时具有良好的ORR、OER和HER功能.以Fe Co-P/PNC为空气阴极组装的水系电池和柔性锌-空气电池的峰值功率密度分别为195.1和90.8 m W cm^(-2),且两种电池均具有优异的充放电性能、长寿命和高柔性.此外,自供能的整体水分解系统表现出较低的(1.71 V)工作电压以驱动10 m A cm^(-2)的电流密度,进一步证实了该催化剂出色的多功能性.

Overwhelming electrochemical oxygen reduction reaction of zinc-nitrogen-carbon from biomass resource chitosan via a facile carbon bath method

Developing high efficiency and low cost electrocatalysts is critical for the enhancement of oxygen reduction reaction(ORR),which is the fundamental for the development and commercialization of renewable energy conversion technology.Herein,zinc-nitrogen-carbon(Zn-N-C)was prepared by using biomass resource chitosan via a facile carbon bath method.The obtained Zn-N-C delivered a high specific surface area(794.7 cm^2/g)together with pore volume(0.49 cm^3/g).During the electrochemical evaluation of oxygen reduction reaction(ORR),Zn-N-C displayed high activity for ORR with an onset pote ntial E0=0.96 VRHE and a half wave potential E1/2=0.86 VRHE,which were more positive than those of the comme rcial 20 wt%Pt/C benchmark catalyst(E0=0.96 VRHE and E1/2=0.81 VRHE).In addition,the ZnN-C catalyst also had a better stability and methanol tolerance than those of the Pt/C catalyst.

Highly efficient green InP-based quantum dot light-emitting diodes regulated by inner alloyed shell component

InP-based quantum dot light-emitting diodes(QLEDs),as less toxic than Cd-free and Pb-free optoelectronic devices,have become the most promising benign alternatives for the next generation lighting and display.However,the development of green-emitting InP-based QLEDs still remains a great challenge to the environmental preparation of InP quantum dots(QDs)and superior device performance.Herein,we reported the highly efficient green-emitting InP-based QLEDs regulated by the inner alloyed shell components.Based on the environmental phosphorus tris(dimethylamino)phosphine((DMA)3P),we obtained highly efficient InP-based QDs with the narrowest full width at half maximum(~35 nm)and highest quantum yield(~97%)by inserting the gradient inner shell layer ZnSe_(x)S_(1-x)without further post-treatment.More importantly,we concretely discussed the effect and physical mechanism of ZnSe_(x)S_(1-x)layer on the performance of QDs and QLEDs through the characterization of structure,luminescence,femtosecond transient absorption,and ultraviolet photoelectron spectroscopy.We demonstrated that the insert inner alloyed shell ZnSe_(x)S_(1-x)provided bifunctionality,which diminished the interface defects upon balancing the lattice mismatch and tailored the energy levels of InP-based QDs which could promote the balanced carrier injection.The resulting QLEDs applying the InP/ZnSe_(0.7)S_(0.3)/ZnS QDs as an emitter layer exhibited a maximum external quantum efficiency of 15.2%with the electroluminescence peak of 532 nm,which was almost the highest record of InP-based pure green-emitting QLEDs.These results demonstrated the applicability and processability of inner shell component engineering in the preparation of high-quallity InP-based QLEDs.

钴铁层状双金属氢氧化物空心多面体用于高效电催化二氧化碳还原

可再生能源驱动电催化二氧化碳还原制备高附加值化学燃料,是一种实现二氧化碳资源化的有效途径.以金属有机骨架(MOF)为模板制备的层状双金属氢氧化物空心多面体已成为当前电催化领域的热门材料.然而,该类材料的高析氢活性严重阻碍了其在电催化二氧化碳还原中的应用.基于此,本文报道了一种在离子液体电解液中可高效稳定电催化二氧化碳还原的钴铁层状双金属氢氧化物空心多面体(CoFe LDH/HP),其最大法拉第转换效率可达86%±3%(-0.9 V相对于可逆氢电极),且可连续电解30 h.实验结果表明此CoFe LDH/HP因其独特的空心结构可暴露更多的活性位点,从而具有更快的电催化二氧化碳还原动力学;理论计算表明CoFe LDH/HP中Co-O-Fe键有利于稳定关键中间体(*COOH)并降低相应的活化势垒.本研究可为其他层状双金属氢氧化物用于二氧化碳固定的设计提供参考.

Highly dispersed Ag clusters for active and stable hydrogen peroxide production

The electrosynthesis of hydrogen peroxide(H2O2)from oxygen reduction reaction(ORR)via a two-electron pathway provides an appealing alternative to the energy-intensive anthraquinone route;however,the development of ORR with high selectivity and durability for H2O2 production is still challenging.Herein,we demonstrate an active and stable catalyst,composing of highly dispersed Ag nanoclusters on N-doped hollow carbon spheres(NC-Ag/NHCS),which can effectively reduce O2 molecules into H2O2 with a selectivity of 89%–91%in a potential range from 0.2 to 0.7 V(vs.reversible hydrogen electrode(RHE))in acidic media.Strikingly,NC-Ag/NHCS achieve a mass activity of 27.1 A·g^(−1) and a yield rate of 408 mmol·gcat.^(−1)·h^(−1) at 0.7 V,both of which are comparable with the best-reported results.Furthermore,NC-Ag/NHCS enable catalyzing H2O2 production with a stable current density over 48-h electrolysis and only about 9.8%loss in selectivity after 10,000 cycles.Theoretical analyses indicate that Ag nanoclusters can contribute more electrons to favor the protonation of adsorbed O2,thus leading to a high H2O2 selectivity.This work confirms the great potential of metal nanocluster-based materials for H2O2 electrosynthesis under ambient conditions.

High-efficiency electrocatalytic NO reduction to NH_(3) by nanoporous VN

Electrocatalytic NO reduction reaction to generate NH_(3)under ambient conditions offers an attractive alternative to the energy-extensive Haber-Bosch route;however,the challenge still lies in the development of cost-effective and high-performance electrocatalysts.Herein,nanoporous VN film is first designed as a highly selective and stable electrocatalyst for catalyzing reduction of NO to NH_(3)with a maximal Faradaic efficiency of 85%and a peak yield rate of 1.05×10^(-7)mol·cm^(-2)·s^(-1)(corresponding to 5,140.8mg·h^(-1)·mg_(cat).^(-1))at-0.6 V vs.reversible hydrogen electrode in acid medium.Meanwhile,this catalyst maintains an excellent activity with negligible current density and NH_(3)yield rate decays over 40 h.Moreover,as a proof-of-concept of Zn-NO battery,it delivers a high power density of 2.0 mW·cm^(-2)and a large NH_(3)yield rate of 0.22×10^(-7)mol·cm^(-2)·s^(-1)(corresponding to 1,077.1mg·h^(-1)·mg_(cat).^(-1)),both of which are comparable to the best-reported results.Theoretical analyses confirm that the VN surface favors the activation and hydrogenation of NO by suppressing the hydrogen evolution.This work highlights that the electrochemical NO reduction is an eco-friendly and energy-efficient strategy to produce NH_(3).