查看更多>>摘要：High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in electrocatalysis.In this study,a Pt/(FeCo-NiCrAl)3O4 nanohybrid using HEO as a support was developed as an efficient catalyst for the hydrogen evolu-tion reaction(HER).Pt/(FeCoNiCrAl)3O4 exhibited high HER activity with a low overpotential of 22 mV at 10 mA·cm-2,outperforming other binary,ternary,and quaternary supports.The HER activity of Pt/(FeCoNi-CrAl)3O4 was higher than that of a commercial Pt/C with a significantly lower Pt loading.The catalyst exhibited good activity and long-term stability(60 h)in an electrolytic water-splitting device.This good activity can be attributed to the fact that the introduction of Pt effectively facilitates electronic interactions between Pt and the HEO.In addi-tion,the HEO substrate was more favorable for dispersing Pt particles,optimizing the electrochemical specific surface area,and significantly reducing the charge resistance of the HER.This study extends the application of HEOs in electrocatalysis and demonstrates the promising prospects of HEOs as supports for electrocatalysts.
Yang YangXiao-Chuan DuanShao-Hui GuoXian-Ming Zhang...
1547-1556页
查看更多>>摘要：Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is important for the sustainable energy economy.Herein,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MNx(M=Co,Fe,Ni)encapsulated in N-doped car-bon layers supported with N-doped graphene sheets(de-noted as M@MNx@NC-NG)are synthesized by facile hydrothermal reaction and nitridation process.During the nitriding process,metal ions in M(tzbc)2(H2O)4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)complexes are reduced to crystalline M cores,accompanied by the for-mation of amorphous MNx shells;the tzbc ligands are in-situ carbonized to form outermost N-doped carbon(NC)layers that connect with inner MNx via M-N-C motifs inherited from the complex precursors and inhibit the transition of MNx from amorphous to crystalline phase.The Co@CoNx@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA-cm-2 and low Tafel slopes of 40 and 85 mV·dec-1 in 0.5 mol-L-1 H2SO4 and 1.0 mol-L-1 KOH electrolytes,respectively.The Co@CoNx@NC-NG retains 97％of the initial overpoten-tial after 100,000 s in both acidic and alkaline media.Such outstanding HER performance originates from the crys-talline-amorphous Co@CoNx that redistributes electrons around the heterointerfaces,facilitating the conversion process of H+/H2O to hydrogen and thereby promoting HER kinetics.The outermost NC layers serve as the armor of Co@CoNx,and graphene nanosheets act as carriers of egg-like Co@CoNx@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.
查看更多>>摘要：Heterogeneous interfaces produced by inter-domain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of NixCoyFe100-x-yO,which grew on Ni foam massively via an ultrafast combustion approach.Particularly,with high-reaction kinetics caused by the reduction treatment at 450 ℃,the less electronegative Fe and Co are more oxyphilic than Ni,which facilitated their co-exsolution and formation of CoFe2O4/NiO oxide with enriched oxygen vacancies.Benefiting from the nanopor-ous framework,heterojunction structure,and oxygen defects,the self-supporting electrodes present rapid char-ge/mass transmission and provide abundant active sites for OER.The optimized sample(R-SNCF4.5)shows low overpotentials of 226 and 324 mV at 10 and 100 mA·cm-2,a small Tafel slope(46.7 mV·dec-1),and excellent stability.The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm-2,under 1.51 V.Density functional theory(DFT)calculations verify that the strong electronic modulation plays a critical part in the CoFe2O4/NiO hybrid by lowering the energy barriers for the rate-determining steps,and Fe sites are the most active OER sites.
查看更多>>摘要：Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely appealing.However,high electron-hole recom-bination rates and insufficient active sites severely limited N2 photoreaction reduction.Herein,we designed and fab-ricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalytic ammonia synthesis performance.As a coupler between Fe and car-bon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradia-tion,and renters the semiconductor a forceful electron donor for the Fe active sites.The accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular nitrogen.Besides,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosh-eets enhanced the stability of photocatalytic nitrogen reduction reaction,making the artificial photocatalytic ammonia synthesis more sustainable for application.This work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.
查看更多>>摘要：It is highly desired to develop efficient photo-catalysts with recycling property for practical application to degrade toxic pollutants.Herein,nanosheet-assembled NiFe2O4 microspheres with commendable activity are successfully synthesized by a facile solvothermal reaction with NH4F as the modifier,and their photoactivities are further improved by coupling with NiO through an in situ growth process.The optimized nickel oxide(NiO)/nickel ferrite(NiFe2O4)microsphere composite(5NiO/NFO-4)exhibits a satisfactory photocatalytic activity for 2,4-dichlorophenol(2,4-DCP)degradation under visible-light irradiation,which is attributed to its wide visible-light response,well-designed hierarchical structure and enhanced charge transfer and separation by coupling NiO as a high-level energy platform to accept electrons.Moreover,it is found that the NiO/NiFe2O4 microsphere photocatalysts can be easily collected and recycled owing to the distinctive magnetic properties.This work provides a feasible route to rational design visible-light-driven photocatalysts with high-activity for environmental reme-diation and purification with good recyclability.
查看更多>>摘要：With the shortage of lithium resources,sodium-ion batteries(SIBs)are considered one of the most promising candidates for lithium-ion batteries.P2-type and O3-type layered oxides are one of the few cathodes that can access high energy density.However,they usually exhibit structural change,capacity decay,and slow Na ion kinetic.Herein,we present layered ternary-phase cathodes with P2,P3 and O3 phases by a lattice doping strategy,which is demonstrated by X-ray diffraction(XRD)refinement.Combining the characteristics of P2,P3 and O3 phases,the layered composites show performance improvement during long-term battery cycling.In particular,Na0.7Li0.1Co0.3-Fe0.3Mn0.3O2(NLCFM)delivers a reversible capacity of 120.1 mAh·g-1 at 0.1C(1.0C=175 mA.g-1)with a superior capacity retention of 72.5％after 1000 cycles at 10.0C.This work offers insights into the development of advanced cathode materials for SIBs.
查看更多>>摘要：Aqueous zinc-ion batteries(AZIBs)have been regarded as prospective rechargeable energy storage devi-ces because of the high theoretical capacity and low redox potential of Zn metal.However,the uncontrollable for-mation of dendrites and the water-induced side reactions at the Zn/electrolyte interface,and the poor reversibility under a high current density(＞2 mA·cm-2)and large area capacity(＞2 mAh·cm-2)still limit the practical applica-tions of AZIBs.Therefore,a strategy that can overcome these difficulties is urgently needed.Here,we introduce an environmentally friendly and low-cost additive,namely urea,to the electrolyte of AZIBs to induce uniform Zn deposition and suppress the side reactions.Measurements of the adsorption behavior,electrochemical characteriza-tion,and observations of the morphology revealed the interfacial modification induced by urea on the Zn/elec-trolyte interface,demonstrating its huge potential in AZIBs.Consequently,the long-term cycling stability(over 2100 h)of a Zn/Zn symmetric cell under a high current density of 5 mA·cm-2 and a capacity of 5 mAh·cm-2 was achieved with a 1 mol·L-1 ZnSO4 electrolyte with the urea additive.Additionally,the assembled Zn/NH4V4O10 full cell with urea exhibited excellent cycling performance and an outstanding average Coulombic efficiency of 99.98％.These results indicate that this is a low-cost and effective additive strategy for realizing highly reversible AZIBs.
查看更多>>摘要：Antimony selenide(Sb2Se3)is one of the per-spective candidates for potassium-ion batteries due to its advanced virtues stem including featured high capacity,fertile reserves and the relative narrow band gap.Despite the unique advantages,it is still plagued by the unstable interface compatibility and poor wider-temperature adaptability.The optimization of microstructure and the construction of inorganic-organic hybrids with a low desolvation barrier and rapid kinetics behaviors are efficient to address these issues.The Sb2Se3 nanorods enclosed by the S-doped carbon layer(SC),further crosslinked by the poly(N-isopropylacry-lamide)(PM)film(PM@Sb2Se3@SC),were artificially fabricated,and it displays the enrichment ion aggregated model as well as contacted ion pair state,the well-tailored cooperation environment of potassium bonds,assuring a homogeneous potassium deposition and an excellent wider-temperature adaptability.The complicated experimental studies and theoretical calculations authenticate the syner-gistic effects of geometric conformation and compositional design for the tremendously enhanced potassium storage.Moreover,the full device over PM@Sb2Se3@SC anode and the potassium Prussian blue cathode manifests impressively durable cycling life and wider-temperature adaptability,verifying the glorious contribution from the finely manipu-lation in solvation structure and potassium bonds to enhancing the potassium storage behaviors.
查看更多>>摘要：Metal coordination compounds(MCCs)are gaining popularity for potassium-ion batteries(PIBs)owing to their tuneable structure,multiple reaction sites,low cost and unique morphology.However,they are gen-erally subjected to intrinsic features of the sluggish ionic diffusion coefficient,low electronic conductivity and slow kinetics.Herein,a new MCC material of cobalt-1,3,5-tri-oxy-2,4,6-triamino-benzo(Co-TB)coordination compound was synthesized and homogenously grown on the surface of graphene nanosheets(GNS),forming a Co-TB@GNS composite with enhanced electronic conductivity and flexible capability.Benefiting from the overall enhanced conductivity,high surface area and abundant activated K-storage sites,Co-TB@GNS electrodes have exhibited superior cycling performance with high reversible capaci-ties(312mAh·g-1 after 100 cycles at 100mA·g-1,224 mAh·g-1 after 500 cycles at 1 A·g-1)and better rate performances compared with the pure Co-TB compound when served as PIB's anodes.Furthermore,multiple in-situ measurement techniques have jointly confirmed that the organic functional groups(C=O,C=N and C=C of benzene rings)and Co2+in Co-TB are the main reversible K-stor-age sites,including in-situ Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD),and partial capacity contribution is originated from GNS by the apparent K-storage behavior in the in-situ XRD pattern,proving the possibility of K-storage for metal-organic materials.
查看更多>>摘要：Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of cation disorder can effectively suppress the detrimental two-phase reaction to realize high capacities in a wide voltage range.However,the continuous capacity decay during cycles has hindered the widespread application of these cathode materials.Inorganic fluorides exhibit excel-lent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially dis-ordered spinel cathode(Li1.6Mn1.6O3.7F0.3,LMOF1.6)was initially applied to investigate the impacts of fluorination on the surface structure and electrochemical performances.The inorganic fluorinated layer,mainly containing LiF,was distributed uniformly on the surface of LMOF1.6 nanoparticles after fluorination for an appropriate time without the turbulence caused by the valency of manganese cation,which improved the capacity retention and rate capability by the suppression of structural damage,parasitic reaction,and cation dissolution.The LMOF1.6 cathode fluorinated for 0.5 h exhibited a capacity of 283.6 mAh·g-1 at 50 mA·g-1 and an enhanced capacity retention of 29.6％after 50 cycles in the voltage range of 1.5-4.8 V,as compared to the pristine LMOF1.6 with only 27.9％capacity retention.
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