Oxygen evolution reaction(OER)is often regarded as a crucial bottleneck in the field of renewable energy storage and conversion.To further accelerate the sluggish kinetics of OER,a cation and anion modulation strategy...Oxygen evolution reaction(OER)is often regarded as a crucial bottleneck in the field of renewable energy storage and conversion.To further accelerate the sluggish kinetics of OER,a cation and anion modulation strategy is reported here,which has been proven to be effective in preparing highly active electrocatalyst.For example,the cobalt,sulfur,and phosphorus modulated nickel hydroxide(denoted as NiCoPSOH)only needs an overpotential of 232 mV to reach a current density of 20 mA cm^(–2),demonstrating excellent OER performances.The cation and anion modulation facilitates the generation of high-valent Ni species,which would activate the lattice oxygen and switch the OER reaction pathway from conventional adsorbate evolution mechanism to lattice oxygen mechanism(LOM),as evidenced by the results of electrochemical measurements,Raman spectroscopy and differential electrochemical mass spectrometry.The LOM pathway of NiCoPSOH is further verified by the theoretical calculations,including the upshift of O 2p band center,the weakened Ni–O bond and the lowest energy barrier of rate-limiting step.Thus,the anion and cation modulated catalyst NiCoPSOH could effectively accelerate the sluggish OER kinetics.Our work provides a new insight into the cation and anion modulation,and broadens the possibility for the rational design of highly active electrocatalysts.展开更多
The adsorption of CO on different lattice oxygen sites in Cu doped CeO_(2)(111)was studied by DFT method,and the geometrical structure and electronic properties of adsorption systems were analyzed.The results showed t...The adsorption of CO on different lattice oxygen sites in Cu doped CeO_(2)(111)was studied by DFT method,and the geometrical structure and electronic properties of adsorption systems were analyzed.The results showed that CO interacted with lattice oxygen on the first layer formed CO_(2).However,when adsorbed on the second layer lattice oxygen,carbonate species were formed with the participation of first layer lattice oxygens,i.e.,CO co-adsorbed on first and second layer lattice oxygens.For the second layer adsorption,the absolute CO adsorption energy was big on the Oss nearby Cu.This kind of carbonates was thermodynamically stable,and it was attributed to the facilitation of Cu on CO adsorption,manifested by an electron migration behavior from the C 2p orbitals to the Cu 3d orbitals.However,the absolute CO adsorption energy on the Oss away from Cu was small.Compared to the formation of carbonates,the formation CO_(2)had very small absolute adsorption energy,suggesting the formed carbonates on second layer was stable.Further,when CO adsorbed on the systems with a carbonate,the absolute CO adsorption energy was significantly smaller than that of the non-carbonated system,indicating that the formation of carbonates inhibited CO oxidation on Cu/CeO_(2)(111).Therefore,the formation of carbonates was unfavorable for CO oxidation reaction on Cu/CeO_(2)(111).The results of this study provide theoretical support for the negative effect of CO_(2)on ceria-based catalysts.展开更多
LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and ...LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and insecurity have hindered their commercial application at scale.In order to overcome these challenges,a kind of tantalum(Ta)doped nickel-rich cathode with reduced size and significantly increased number of primary particles is prepared by combining mechanical fusion with high temperature co-calcination.The elaborately designed micro-morphology of small and uniform primary particles effectively eliminates the local strain accumulation caused by the random orientation of primary particles.Moreover,the uniform distribution of small primary particles stabilizes the spherical secondary particles,thus effectively inhibiting the formation and extension of microcracks.In addition,the formed strong Ta-O bonds restrain the release of lattice oxygen,which greatly increases the structural stability and safety of NCM materials.Therefore,the cathode material with the designed primary particle morphology shows superior electrochemical performance.The 1 mol%Ta-modified cathode(defined as1%Ta-NCM)shows a capacity retention of 97.5%after 200 cycles at 1 C and a rate performance of 137.3 mAh g^(-1)at 5 C.This work presents promising approach to improve the structural stability and safety of nickel-rich NCM.展开更多
Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaus...Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.展开更多
The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically appl...The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically applied.The traditional lattice oxygen oxidation mechanism(LOM)offers an advantageous route by circumventing the formation of M-OOH^(*)in the adsorption evolution mechanism(AEM),thus enhancing the reaction kinetics of the OER but resulting in possible structural destabilization due to the decreased M–O bond order.Fortunately,the asymmetry of tetrahedral and octahedral sites in transition metal spinel oxides permits the existence of non-bonding oxygen,which could be activated by rational band structure design for direct O-O coupling,where the M–O bond maintains its initial bond order.Here,non-bonding oxygen was introduced into NiFe_(2)O_(4)via annealing in an oxygen-deficient atmosphere.Then,in-situ grown sulfate species on octahedral nickel sites significantly improved the reactivity of the non-bonding oxygen electrons,thereby facilitating the transformation of the redox center from metal to oxygen.LOM based on non-bonding oxygen(LOMNB)was successfully activated within NiFe_(2)O_(4),exhibiting a low overpotential of 206 mV to achieve a current density of 10 mA cm^(-2)and excellent durability of stable operation for over 150 h.Additionally,catalysts featuring varying band structures were synthesized for comparative analysis,and it was found that the reversible redox processes of non-bonding oxygen and the accumulation of non-bonding oxygen species containing 2p holes are critical prerequisites for triggering and sustaining the LOMNB pathway in transition metal spinel oxides.These findings may provide valuable insights for the future development of spinel-oxide-based LOM catalysts.展开更多
Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as se...Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.展开更多
The rational design of metal-organic frameworks(MOFs)provides potential opportunities for improving energy conversion efficiency.However,developing efficient MOF-based electrocatalysts remains highly challenging.Herei...The rational design of metal-organic frameworks(MOFs)provides potential opportunities for improving energy conversion efficiency.However,developing efficient MOF-based electrocatalysts remains highly challenging.Herein,a strategy involving strain engineering is developed to promote the electrocatalytic performance of MOFs by optimizing electronic configuration and improving the active site.As expected,the optimized CoFe–BDC–NO_(2)exhibits a low overpotential of 292 mV at 10 mA cm^(–2)and a small Tafel slope of 31.6 mV dec^(–1)as oxygen evolution reaction(OER)electrocatalyst.Notably,when CoFe–BDC–NO_(2)is prepared on Nickel foam(NF),the overpotential is only 345 mV at 1 A cm^(–2),which ensures efficient water oxidation properties.Integrating CoFe–BDC–NO_(2)/NF anode in membrane electrode assembly(MEA)for overall water splitting and CO_(2)reduction reaction(CO_(2)RR)tests,the results show that the cell voltages of CoFe–BDC–NO_(2)/NF are 3.14 and 3.09 V at 300 mA cm^(–2)(25℃),respectively,indicating that MOFs have various practical application prospects.The research of the structure-performance relationship reveals the lattice oxygen oxidation mechanism(LOM)where the Co-O-Fe bond is formed during the OER process by changing the electronic environment and coordination structure of CoFe–BDC–NO_(2),and with high valence Co as active center,which provides a deep understanding of the structure design of MOFs and their structural transformation during OER.展开更多
Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and comp...Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and complex by-products separation.To this end,we introduce the lattice oxygen oxidation mechanism(LOM),propelling a novel UOR route using a modified CoFe layered double hydroxide(LDH)catalyst termed CFRO-7.Theoretical calculations and in-situ characterizations highlight the activated lattice oxygen(O_(L))within CFRO-7 as pivotal sites for UOR,optimizing the reaction pathway and accelerating the kinetics.For the urea overall electrolysis application,the LOM route only requires a low voltage of 1.54 V to offer a high current of 100 mA cm^(-2) for long-term utilization(>48 h).Importantly,the by-product NCO^(-)−is significantly suppressed,while the CO_(2)2/N_(2) separation is efficiently achieved.This work proposed a pioneering paradigm,invoking the LOM pathway in urea electrolysis to expedite reaction dynamics and enhance product selectivity.展开更多
In this paper, the partial oxidation of methane to synthesis gas using lattice oxygen of La1- SrxMO3-λ (M=Fe, x ...In this paper, the partial oxidation of methane to synthesis gas using lattice oxygen of La1- SrxMO3-λ (M=Fe, x Mn) perovskite oxides instead of molecular oxygen was investigated. The redox circulation between 11% O2/Ar flow and 11% CH4/He flow at 900℃ shows that methane can be oxidized to CO and H2 with a selectivity of over 90.7% using the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite oxides in an appropriate reaction condition, while the lost lattice x oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite x oxides instead of molecular oxygen to react with methane to synthesis gas in the redox mode.展开更多
In this paper, selective oxidation of n-butane to maleic anhydride (MA) and partial oxidation of methane to synthesis gas with lattice oxygen instead of molecular oxygen are investigated. For the oxidation of butane t...In this paper, selective oxidation of n-butane to maleic anhydride (MA) and partial oxidation of methane to synthesis gas with lattice oxygen instead of molecular oxygen are investigated. For the oxidation of butane to MA in the absence of molecular oxygen, the Ce-Fe promoted VPO catalyst has more available lattice oxygen and provides higher conversion and selectivity than that of the unpromoted one. It is supposed that the introduction of Ce-Fe complex oxides improves redox performance of VPO catalyst and increases the activity of lattice oxygen. For partial oxidation of methane to synthesis gas over LaFeO3 and La0.8Sr0.2FeO3 oxides, the reaction with flow switched between 11% O2-Ar and 11% CH4-He at 900℃ was carried out. The results show that methane can be oxidized to CO and H2 with selectivity over 93% by the lattice oxygen of the catalyst in an appropriate reaction condition, while the lost lattice oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of the LaFeO3 and La0.8Sr0.2FeO3 catalyst instead of molecular oxygen to react with methane to synthesis gas in the redox mode.展开更多
Double-perovskite type oxide LaSrFeCoO（LSFCO） was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Two different oxidation routes,steam-oxidat...Double-perovskite type oxide LaSrFeCoO（LSFCO） was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Two different oxidation routes,steam-oxidation and steam-air-stepwise-oxidation, were applied to investigate the recovery behaviors of the lattice oxygen in the oxygen carrier. The characterizations of the oxide were determined by X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, hydrogen temperature-programmed reduction（H-TPR） and scanning electron microscopy（SEM）. The fresh sample LSFCO exhibits a monocrystalline perovskite structure with cubic symmetry and high crystallinity, except for a little impurity phase due to the antisite defect of Fe/Co disorder. The deconvolution distribution of XPS patterns indicated that Co,and Fe are predominantly in an oxidized state(Feand Fe) and(Coand Co), while O 1s exists at three species of lattice oxygen, chemisorbed oxygen and physical adsorbed oxygen. The double perovskite structure and chemical composition recover to the original state after the steam and air oxidation, while the Co ion cannot incorporate into the double perovskite structure and thus form the CoO just via individual steam oxidation. In comparison to the two different oxidation routes, the sample obtained by steam-oxidation exhibits even higher CHconversion, CO and Hselectivity and stronger hydrogen generation capacity.展开更多
Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution...Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.展开更多
Density functional theory calculations were carried out to investigate the influence of doping transition metal(TM) ions into the ceria surface on the activation of surface lattice oxygen atoms. For this purpose, the ...Density functional theory calculations were carried out to investigate the influence of doping transition metal(TM) ions into the ceria surface on the activation of surface lattice oxygen atoms. For this purpose, the structure and stability of the most stable(111) surface termination of CeO2 modified by TM ions was determined. Except for Zr and Pt dopants that preserve octahedral oxygen coordination, the TM dopants prefer a square-planar coordination when substituting the surface Ce ions. The surface construction from octahedral to square-planar is facile for all TM dopants, except for Pt(1.14 e V) and Zr(square-planar coordination unstable). Typically, the ionic radius of tetravalent TM cations is much smaller than that of Ce4+, resulting a significant tensile-strained lattice and explaining the lowered oxygen vacancy formation energy. Except for Zr, the square-planar structure is the preferred one when one oxygen vacancy is created. Thermodynamic analysis shows that TM-doped CeO2 surfaces contain oxygen defects under typical conditions of environmental catalysis. A case of practical importance is the facile lattice oxygen activation in Zr-doped CeO2(111), which benefits CO oxidation. The findings emphasize the origin of lattice oxygen activation and the preferred location of TM dopants in TM-ceria solid solution catalysts.展开更多
The conversion of methane to syngas(H_(2) and CO)is an important route to produce high value-added products.Oxidize methane into syngas in the absence of gaseous oxidants is an economical route.In this work,NiO-MgO co...The conversion of methane to syngas(H_(2) and CO)is an important route to produce high value-added products.Oxidize methane into syngas in the absence of gaseous oxidants is an economical route.In this work,NiO-MgO composite is successfully synthesized via an impregnation method.At 764 K,methane is directly converted to syngas on the NiO-MgO without gaseous oxidants.A synergistic effect of NiO and MgO was observed,in which NiO induced lattice oxygen of MgO mobility to oxidize methane and suppressed the formation of intermediates for side reaction.As a result,NiO-MgO exhibited enhancement of catalytic activity with the H2 production rate of 1241.0µmol g^(-1) min^(-1),which was 3.4 times higher than that of pure MgO.This work provides a direct guidance to understand of methane oxidation via lattice oxygen under low temperature(<773 K).展开更多
Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,wh...Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,which leads to co-migration of transition metal ions and oxygen vacancies,causing structural instability.In this work,we propose a pre-activation strategy driven by chemical impregnation to modulate the chemical state of surface lattice oxygen,thus regulating the structural and electrochemical properties of the cathodes.In-situ X-ray diffraction confirms that materials based on activated oxygen configuration have higher structural stability.More importantly,this novel efficient strategy endows the cathodes having a lower surface charge transfer barrier and higher Li+transfer kinetics characteristic and ameliorates its inherent issues.The optimized cathode exhibits excellent electrochemical performance:after 300 cycles,high capacity(from 238 m Ah g^(-1)to 193 m Ah g^(-1)at 1 C)and low voltage attenuation(168 mV)are obtained.Overall,this modulated surface lattice oxygen strategy improves the electrochemical activity and structural stability,providing an innovative idea to obtain high-capacity Co-free Li-rich cathodes for next-generation Li-ion batteries.展开更多
The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high...The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high-voltage cycling,which is related to the phase transformation and the surface sides reactions caused by the lattice oxygen evolution.Here,the simultaneous construction of a Mg,Ti-based surface integrated layer and bulk doping through Mg,Ti surface treatment could suppress the lattice oxygen evolution of Nirich material at deep charging.More importantly,Mg and Ti are co-doped into the particles surface to form an Mg_(2)TiO_(4) and Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with Mg and Ti vacancies.In the constructed surface integrated layer,the reverse electric field in the Mg_(2)TiO_(4) effectively suppressed the outward migration of the lattice oxygen anions,while Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with high electronic conductivity and good lithium ion conductor could effectively maintained the stability of the reaction interface during highvoltage cycling.Meanwhile,bulk Mg and Ti co-doping can mitigate the migration of Ni ions in the bulk to keep the stability of transition metal–oxygen(M-O)bond at deep charging.As a result,the NCM@MTP cathode shows excellent long cycle stability at high-voltage charging,which keep high capacity retention of 89.3%and 84.3%at 1 C after 200 and 100 cycles under room and elevated temperature of 25 and 55°C,respectively.This work provides new insights for manipulating the surface chemistry of electrode materials to suppress the lattice oxygen evolution at high charging voltage.展开更多
Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alt...Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.展开更多
The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER p...The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER process.We investigated the potential of disordered rocksalts as catalysts for accelerating the OER through the LOM process,leveraging their unique metastable Li-O-Li bond states.Theoretical calculations were employed to predict the catalytic pathways and activities of disordered rocksalts(DRX),such as Li_(1.2)Co_(0.4)Ti_(0.5)O_(2)(LCTO).The results revealed that benefiting from the unhybridized Li-O electronic orbitals and the resulting metastable states of Li-O-Li bonds in DRX,LCTO exhibited a typical LOM pathway,and the lattice oxygen was easily activated and participated in the OER.The experimental results showed that LCTO exhibited a remarkable pH-dependent OER activity through the LOM pathway,with an overpotential of 241 mV at a current density of 10 mA/cm^(2),and excellent long-term stability.This work provides a novel chemical space for designing highly active and stable OER electrocatalysts by leveraging the LOM reaction pathway.展开更多
Excellent performances promoted by lattice oxygen have attracted wide attention for catalytic degradation of volatile organic compounds(VOCs).However,how to control the continuous regeneration of lattice oxygen from t...Excellent performances promoted by lattice oxygen have attracted wide attention for catalytic degradation of volatile organic compounds(VOCs).However,how to control the continuous regeneration of lattice oxygen from the support is seldom reported.In this study,we selected sepiolite supported manganese-cobalt oxides(Co_(x)Mn_(100-x)O_(y))as model catalysts by tuning Co/(Co+Mn)mass ratio(x=3%,10%,15%,and 20%)to enhance toluene degradation efficiency,owing to lattice oxygen regeneration by redox cycle existing at the interface and Mn species with high valence state,initiated by cobalt catalytic performance under the role of crystal field stability phase.The results of activity test show that the sepiolite-Co_(15)Mn_(85)O_(y)catalyst exhibit outperformances at 193℃with 10,000 h^(-1)GHSV.In addition,the catalyst existed at the bottom of the"volcano"curve correlated T_(50)or T_(90)with Co/(Co+Mn)weight ratio is sepiolite-Co_(15)Mn_(85)O_(y),conforming its outperformance.Further characterized by investigating active sites structural and electronic properties,the essential of superior catalytic activity is attributed to the grands of lattice oxygen continuous formation resulted from redox engineering based on the high atomic ratio of surface lattice oxygen with continuous refilled from the support and that of Mn^(4+)/Mn^(3+)cycle initiated by cobalt catalytic behaviors.All in all,redox engineering,not only promotes grands of active species reversible regeneration,but supplies an alternative catalyst design strategy towards the terrific efficiency-to-cost ratio performance.展开更多
Concurrent activation of lattice oxygen(O_L)and molecular oxygen(O_(2))is crucial for the efficient catalytic oxidation of biomass-derived molecules over metal oxides.Herein,we report that the introduction of ultralow...Concurrent activation of lattice oxygen(O_L)and molecular oxygen(O_(2))is crucial for the efficient catalytic oxidation of biomass-derived molecules over metal oxides.Herein,we report that the introduction of ultralow-loading of Ru single atoms(0.42 wt%)into Mn_(2)O_(3)matrix(0.4%Ru-Mn_(2)O_(3))greatly boosts its catalytic activity for the aerobic oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA).The FDCA productivity over the 0.4%Ru-Mn_(2)O_(3)(5.4 mmol_(FDCA)g_(cat)h^(-1))is 4.9 times higher than the Mn_(2)O_(3).Especially,this FDCAproductivity is also significantly higher than that of existing Ru and Mn-based catalysts.Experimental and theoretical investigations discovered that the Ru single atom facilitated the formation of oxygen vacancy(O_(v))in the catalyst,which synergistically weakened the Mn-O bond and promoted the activation of O_L.The co-presence of Ru single atoms and O_(v)also promote the adsorption and activation of both O_(2)and HMF.Consequently,the dehydrogenation reaction energy barrier of the rate-determining step was reduced via both the O_L and chemisorbed O_(2)dehydrogenation pathways,thus boosting the catalytic oxidation reactions.展开更多
文摘Oxygen evolution reaction(OER)is often regarded as a crucial bottleneck in the field of renewable energy storage and conversion.To further accelerate the sluggish kinetics of OER,a cation and anion modulation strategy is reported here,which has been proven to be effective in preparing highly active electrocatalyst.For example,the cobalt,sulfur,and phosphorus modulated nickel hydroxide(denoted as NiCoPSOH)only needs an overpotential of 232 mV to reach a current density of 20 mA cm^(–2),demonstrating excellent OER performances.The cation and anion modulation facilitates the generation of high-valent Ni species,which would activate the lattice oxygen and switch the OER reaction pathway from conventional adsorbate evolution mechanism to lattice oxygen mechanism(LOM),as evidenced by the results of electrochemical measurements,Raman spectroscopy and differential electrochemical mass spectrometry.The LOM pathway of NiCoPSOH is further verified by the theoretical calculations,including the upshift of O 2p band center,the weakened Ni–O bond and the lowest energy barrier of rate-limiting step.Thus,the anion and cation modulated catalyst NiCoPSOH could effectively accelerate the sluggish OER kinetics.Our work provides a new insight into the cation and anion modulation,and broadens the possibility for the rational design of highly active electrocatalysts.
基金supported by National Natural Science Foundation of China(22379059)Applied Basic Research Program Project of Liaoning Province(2023JH2/101300224)+4 种基金Service Local Project of the Education Department of Liaoning Province(Enlisting and Leading)(LJKFZ20220201)General Project of the Educational Department of Liaoning Province(LJKMZ20220728)supported by Talent Scientific Research Fund of Liaoning Petrochemical University(2019-XJJL-028)Collaborative Innovation Project of Beijing-Tianjin-Hebei(Tianjin)(22PTXTHZ00020)Basic scientific research project of Liaoning Provincial Department of Education(LJ212410148019)。
文摘The adsorption of CO on different lattice oxygen sites in Cu doped CeO_(2)(111)was studied by DFT method,and the geometrical structure and electronic properties of adsorption systems were analyzed.The results showed that CO interacted with lattice oxygen on the first layer formed CO_(2).However,when adsorbed on the second layer lattice oxygen,carbonate species were formed with the participation of first layer lattice oxygens,i.e.,CO co-adsorbed on first and second layer lattice oxygens.For the second layer adsorption,the absolute CO adsorption energy was big on the Oss nearby Cu.This kind of carbonates was thermodynamically stable,and it was attributed to the facilitation of Cu on CO adsorption,manifested by an electron migration behavior from the C 2p orbitals to the Cu 3d orbitals.However,the absolute CO adsorption energy on the Oss away from Cu was small.Compared to the formation of carbonates,the formation CO_(2)had very small absolute adsorption energy,suggesting the formed carbonates on second layer was stable.Further,when CO adsorbed on the systems with a carbonate,the absolute CO adsorption energy was significantly smaller than that of the non-carbonated system,indicating that the formation of carbonates inhibited CO oxidation on Cu/CeO_(2)(111).Therefore,the formation of carbonates was unfavorable for CO oxidation reaction on Cu/CeO_(2)(111).The results of this study provide theoretical support for the negative effect of CO_(2)on ceria-based catalysts.
基金financial support provided by the National Natural Science Foundation of China(52271201)the Science and Technology Department of Sichuan Province(2025NSFTD0005,2022YFG0100,2022ZYD0045)。
文摘LiNixCoyMn_(2)O_(2)(NCM,x≥0.8,x+y+z=1)cathodes have attracted much attention due to their high specific capacity and low cost.However,severe anisotropic volume changes and oxygen evolution induced capacity decay and insecurity have hindered their commercial application at scale.In order to overcome these challenges,a kind of tantalum(Ta)doped nickel-rich cathode with reduced size and significantly increased number of primary particles is prepared by combining mechanical fusion with high temperature co-calcination.The elaborately designed micro-morphology of small and uniform primary particles effectively eliminates the local strain accumulation caused by the random orientation of primary particles.Moreover,the uniform distribution of small primary particles stabilizes the spherical secondary particles,thus effectively inhibiting the formation and extension of microcracks.In addition,the formed strong Ta-O bonds restrain the release of lattice oxygen,which greatly increases the structural stability and safety of NCM materials.Therefore,the cathode material with the designed primary particle morphology shows superior electrochemical performance.The 1 mol%Ta-modified cathode(defined as1%Ta-NCM)shows a capacity retention of 97.5%after 200 cycles at 1 C and a rate performance of 137.3 mAh g^(-1)at 5 C.This work presents promising approach to improve the structural stability and safety of nickel-rich NCM.
文摘Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.
文摘The oxygen evolution reaction(OER)serves as a fundamental half–reaction in the electrolysis of water for hydrogen production,which is restricted by the sluggish OER reaction kinetics and unable to be practically applied.The traditional lattice oxygen oxidation mechanism(LOM)offers an advantageous route by circumventing the formation of M-OOH^(*)in the adsorption evolution mechanism(AEM),thus enhancing the reaction kinetics of the OER but resulting in possible structural destabilization due to the decreased M–O bond order.Fortunately,the asymmetry of tetrahedral and octahedral sites in transition metal spinel oxides permits the existence of non-bonding oxygen,which could be activated by rational band structure design for direct O-O coupling,where the M–O bond maintains its initial bond order.Here,non-bonding oxygen was introduced into NiFe_(2)O_(4)via annealing in an oxygen-deficient atmosphere.Then,in-situ grown sulfate species on octahedral nickel sites significantly improved the reactivity of the non-bonding oxygen electrons,thereby facilitating the transformation of the redox center from metal to oxygen.LOM based on non-bonding oxygen(LOMNB)was successfully activated within NiFe_(2)O_(4),exhibiting a low overpotential of 206 mV to achieve a current density of 10 mA cm^(-2)and excellent durability of stable operation for over 150 h.Additionally,catalysts featuring varying band structures were synthesized for comparative analysis,and it was found that the reversible redox processes of non-bonding oxygen and the accumulation of non-bonding oxygen species containing 2p holes are critical prerequisites for triggering and sustaining the LOMNB pathway in transition metal spinel oxides.These findings may provide valuable insights for the future development of spinel-oxide-based LOM catalysts.
文摘Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.
基金financial support from the National Natural Science Foundation of China(Nos.21975175,21878202,22308246)the Fundamental Research Program of Shanxi Province(No.202203021212266).
文摘The rational design of metal-organic frameworks(MOFs)provides potential opportunities for improving energy conversion efficiency.However,developing efficient MOF-based electrocatalysts remains highly challenging.Herein,a strategy involving strain engineering is developed to promote the electrocatalytic performance of MOFs by optimizing electronic configuration and improving the active site.As expected,the optimized CoFe–BDC–NO_(2)exhibits a low overpotential of 292 mV at 10 mA cm^(–2)and a small Tafel slope of 31.6 mV dec^(–1)as oxygen evolution reaction(OER)electrocatalyst.Notably,when CoFe–BDC–NO_(2)is prepared on Nickel foam(NF),the overpotential is only 345 mV at 1 A cm^(–2),which ensures efficient water oxidation properties.Integrating CoFe–BDC–NO_(2)/NF anode in membrane electrode assembly(MEA)for overall water splitting and CO_(2)reduction reaction(CO_(2)RR)tests,the results show that the cell voltages of CoFe–BDC–NO_(2)/NF are 3.14 and 3.09 V at 300 mA cm^(–2)(25℃),respectively,indicating that MOFs have various practical application prospects.The research of the structure-performance relationship reveals the lattice oxygen oxidation mechanism(LOM)where the Co-O-Fe bond is formed during the OER process by changing the electronic environment and coordination structure of CoFe–BDC–NO_(2),and with high valence Co as active center,which provides a deep understanding of the structure design of MOFs and their structural transformation during OER.
基金supported by Fundamental Research Funds for the Central Universities(B220202062)supported by Key Program of National Natural Science Foundation of China(92047201,92047303,52102237)+1 种基金National Science Funds for Creative Research Groups of China(51421006)supported by Postdoctoral Science Foundations of China and Jiangsu Province(2021M690861,2022T150183,2021K065A)。
文摘Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and complex by-products separation.To this end,we introduce the lattice oxygen oxidation mechanism(LOM),propelling a novel UOR route using a modified CoFe layered double hydroxide(LDH)catalyst termed CFRO-7.Theoretical calculations and in-situ characterizations highlight the activated lattice oxygen(O_(L))within CFRO-7 as pivotal sites for UOR,optimizing the reaction pathway and accelerating the kinetics.For the urea overall electrolysis application,the LOM route only requires a low voltage of 1.54 V to offer a high current of 100 mA cm^(-2) for long-term utilization(>48 h).Importantly,the by-product NCO^(-)−is significantly suppressed,while the CO_(2)2/N_(2) separation is efficiently achieved.This work proposed a pioneering paradigm,invoking the LOM pathway in urea electrolysis to expedite reaction dynamics and enhance product selectivity.
文摘In this paper, the partial oxidation of methane to synthesis gas using lattice oxygen of La1- SrxMO3-λ (M=Fe, x Mn) perovskite oxides instead of molecular oxygen was investigated. The redox circulation between 11% O2/Ar flow and 11% CH4/He flow at 900℃ shows that methane can be oxidized to CO and H2 with a selectivity of over 90.7% using the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite oxides in an appropriate reaction condition, while the lost lattice x oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of La1- SrxFeO3-λ (x≤0.2) perovskite x oxides instead of molecular oxygen to react with methane to synthesis gas in the redox mode.
基金Supported by China Petroleum & Chemical Corporation(No.X502015)and the National Natural Science Foundation of China(No. 29792073-2)
文摘In this paper, selective oxidation of n-butane to maleic anhydride (MA) and partial oxidation of methane to synthesis gas with lattice oxygen instead of molecular oxygen are investigated. For the oxidation of butane to MA in the absence of molecular oxygen, the Ce-Fe promoted VPO catalyst has more available lattice oxygen and provides higher conversion and selectivity than that of the unpromoted one. It is supposed that the introduction of Ce-Fe complex oxides improves redox performance of VPO catalyst and increases the activity of lattice oxygen. For partial oxidation of methane to synthesis gas over LaFeO3 and La0.8Sr0.2FeO3 oxides, the reaction with flow switched between 11% O2-Ar and 11% CH4-He at 900℃ was carried out. The results show that methane can be oxidized to CO and H2 with selectivity over 93% by the lattice oxygen of the catalyst in an appropriate reaction condition, while the lost lattice oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of the LaFeO3 and La0.8Sr0.2FeO3 catalyst instead of molecular oxygen to react with methane to synthesis gas in the redox mode.
基金The financial support of the National Natural Science Foundation of China(51406208,51406214)supported by the Science&Technology Research Project of Guangdong Province(2015A010106009)the support of Key Laboratory of Renewable Energy,Chinese Academy of Sciences(Y607j51001)
文摘Double-perovskite type oxide LaSrFeCoO（LSFCO） was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Two different oxidation routes,steam-oxidation and steam-air-stepwise-oxidation, were applied to investigate the recovery behaviors of the lattice oxygen in the oxygen carrier. The characterizations of the oxide were determined by X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, hydrogen temperature-programmed reduction（H-TPR） and scanning electron microscopy（SEM）. The fresh sample LSFCO exhibits a monocrystalline perovskite structure with cubic symmetry and high crystallinity, except for a little impurity phase due to the antisite defect of Fe/Co disorder. The deconvolution distribution of XPS patterns indicated that Co,and Fe are predominantly in an oxidized state(Feand Fe) and(Coand Co), while O 1s exists at three species of lattice oxygen, chemisorbed oxygen and physical adsorbed oxygen. The double perovskite structure and chemical composition recover to the original state after the steam and air oxidation, while the Co ion cannot incorporate into the double perovskite structure and thus form the CoO just via individual steam oxidation. In comparison to the two different oxidation routes, the sample obtained by steam-oxidation exhibits even higher CHconversion, CO and Hselectivity and stronger hydrogen generation capacity.
基金the support from the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(Nos.22008170,22278307,22222808,21978200)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformationsthe Tianjin Research Innovation Project for Postgraduate Students(2022B KYZ035)。
文摘Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.
基金supported by The Netherlands Organization for Scientific Research(NWO)through a Vici grant and Nuffic fundingfunding from the European Union’s Horizon 2020 research and innovation programme under grant No.686086(Partial-PGMs)。
文摘Density functional theory calculations were carried out to investigate the influence of doping transition metal(TM) ions into the ceria surface on the activation of surface lattice oxygen atoms. For this purpose, the structure and stability of the most stable(111) surface termination of CeO2 modified by TM ions was determined. Except for Zr and Pt dopants that preserve octahedral oxygen coordination, the TM dopants prefer a square-planar coordination when substituting the surface Ce ions. The surface construction from octahedral to square-planar is facile for all TM dopants, except for Pt(1.14 e V) and Zr(square-planar coordination unstable). Typically, the ionic radius of tetravalent TM cations is much smaller than that of Ce4+, resulting a significant tensile-strained lattice and explaining the lowered oxygen vacancy formation energy. Except for Zr, the square-planar structure is the preferred one when one oxygen vacancy is created. Thermodynamic analysis shows that TM-doped CeO2 surfaces contain oxygen defects under typical conditions of environmental catalysis. A case of practical importance is the facile lattice oxygen activation in Zr-doped CeO2(111), which benefits CO oxidation. The findings emphasize the origin of lattice oxygen activation and the preferred location of TM dopants in TM-ceria solid solution catalysts.
基金financially supported by the Sichuan Provincial International Cooperation Project,China(Nos.2019YFH0164 and 2021YFH0055).
文摘The conversion of methane to syngas(H_(2) and CO)is an important route to produce high value-added products.Oxidize methane into syngas in the absence of gaseous oxidants is an economical route.In this work,NiO-MgO composite is successfully synthesized via an impregnation method.At 764 K,methane is directly converted to syngas on the NiO-MgO without gaseous oxidants.A synergistic effect of NiO and MgO was observed,in which NiO induced lattice oxygen of MgO mobility to oxidize methane and suppressed the formation of intermediates for side reaction.As a result,NiO-MgO exhibited enhancement of catalytic activity with the H2 production rate of 1241.0µmol g^(-1) min^(-1),which was 3.4 times higher than that of pure MgO.This work provides a direct guidance to understand of methane oxidation via lattice oxygen under low temperature(<773 K).
基金the National Natural Science Foundation of China(51902072 and 22075062)the Heilongjiang Touyan Team(HITTY-20190033)+2 种基金the Heilongjiang Province“hundred million”project science and technology major special projects(2019ZX09A02)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology No.2020DX11)the Fundamental Research Funds for the Central Universities(FRFCU5710051922)。
文摘Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,which leads to co-migration of transition metal ions and oxygen vacancies,causing structural instability.In this work,we propose a pre-activation strategy driven by chemical impregnation to modulate the chemical state of surface lattice oxygen,thus regulating the structural and electrochemical properties of the cathodes.In-situ X-ray diffraction confirms that materials based on activated oxygen configuration have higher structural stability.More importantly,this novel efficient strategy endows the cathodes having a lower surface charge transfer barrier and higher Li+transfer kinetics characteristic and ameliorates its inherent issues.The optimized cathode exhibits excellent electrochemical performance:after 300 cycles,high capacity(from 238 m Ah g^(-1)to 193 m Ah g^(-1)at 1 C)and low voltage attenuation(168 mV)are obtained.Overall,this modulated surface lattice oxygen strategy improves the electrochemical activity and structural stability,providing an innovative idea to obtain high-capacity Co-free Li-rich cathodes for next-generation Li-ion batteries.
基金supported by the National Natural Science Foundation of China(51902108,51762006,51964013)the Special Projects for Central Government to Guide Local Technological Development(GUIKE ZY20198008)+2 种基金the Guangxi InnovationDriven Development Subject(GUIKE AA19182020,GUIKE AA19254004)the Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20999012,GUIKE AD20297086)the Special Fund for Guangxi Distinguished Expert。
文摘The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high-voltage cycling,which is related to the phase transformation and the surface sides reactions caused by the lattice oxygen evolution.Here,the simultaneous construction of a Mg,Ti-based surface integrated layer and bulk doping through Mg,Ti surface treatment could suppress the lattice oxygen evolution of Nirich material at deep charging.More importantly,Mg and Ti are co-doped into the particles surface to form an Mg_(2)TiO_(4) and Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with Mg and Ti vacancies.In the constructed surface integrated layer,the reverse electric field in the Mg_(2)TiO_(4) effectively suppressed the outward migration of the lattice oxygen anions,while Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with high electronic conductivity and good lithium ion conductor could effectively maintained the stability of the reaction interface during highvoltage cycling.Meanwhile,bulk Mg and Ti co-doping can mitigate the migration of Ni ions in the bulk to keep the stability of transition metal–oxygen(M-O)bond at deep charging.As a result,the NCM@MTP cathode shows excellent long cycle stability at high-voltage charging,which keep high capacity retention of 89.3%and 84.3%at 1 C after 200 and 100 cycles under room and elevated temperature of 25 and 55°C,respectively.This work provides new insights for manipulating the surface chemistry of electrode materials to suppress the lattice oxygen evolution at high charging voltage.
基金The work is supported by The Department of Education of Heilongjiang Province.
文摘Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.
基金supported by the National Natural Science Foundation of China(Nos.52177220,52231008)Key Research and Development Program of Hainan Province(ZDYF2022GXJS006)。
文摘The lattice oxygen oxidation mechanism(LOM)provides an efficient pathway for accelerating the oxygen evolution reaction(OER)in certain electrocatalysts by activating and involving lattice oxygen in the catalytic OER process.We investigated the potential of disordered rocksalts as catalysts for accelerating the OER through the LOM process,leveraging their unique metastable Li-O-Li bond states.Theoretical calculations were employed to predict the catalytic pathways and activities of disordered rocksalts(DRX),such as Li_(1.2)Co_(0.4)Ti_(0.5)O_(2)(LCTO).The results revealed that benefiting from the unhybridized Li-O electronic orbitals and the resulting metastable states of Li-O-Li bonds in DRX,LCTO exhibited a typical LOM pathway,and the lattice oxygen was easily activated and participated in the OER.The experimental results showed that LCTO exhibited a remarkable pH-dependent OER activity through the LOM pathway,with an overpotential of 241 mV at a current density of 10 mA/cm^(2),and excellent long-term stability.This work provides a novel chemical space for designing highly active and stable OER electrocatalysts by leveraging the LOM reaction pathway.
基金Supported by the National Natural Science Foundation of China(21707023)Provincial Key Research and Development Plan of Hunan Province(2018SK2034)New Faculty Start-Up Funding from Xiangtan University(18QDZ16)。
文摘Excellent performances promoted by lattice oxygen have attracted wide attention for catalytic degradation of volatile organic compounds(VOCs).However,how to control the continuous regeneration of lattice oxygen from the support is seldom reported.In this study,we selected sepiolite supported manganese-cobalt oxides(Co_(x)Mn_(100-x)O_(y))as model catalysts by tuning Co/(Co+Mn)mass ratio(x=3%,10%,15%,and 20%)to enhance toluene degradation efficiency,owing to lattice oxygen regeneration by redox cycle existing at the interface and Mn species with high valence state,initiated by cobalt catalytic performance under the role of crystal field stability phase.The results of activity test show that the sepiolite-Co_(15)Mn_(85)O_(y)catalyst exhibit outperformances at 193℃with 10,000 h^(-1)GHSV.In addition,the catalyst existed at the bottom of the"volcano"curve correlated T_(50)or T_(90)with Co/(Co+Mn)weight ratio is sepiolite-Co_(15)Mn_(85)O_(y),conforming its outperformance.Further characterized by investigating active sites structural and electronic properties,the essential of superior catalytic activity is attributed to the grands of lattice oxygen continuous formation resulted from redox engineering based on the high atomic ratio of surface lattice oxygen with continuous refilled from the support and that of Mn^(4+)/Mn^(3+)cycle initiated by cobalt catalytic behaviors.All in all,redox engineering,not only promotes grands of active species reversible regeneration,but supplies an alternative catalyst design strategy towards the terrific efficiency-to-cost ratio performance.
基金financially supported by National Natural Science Foundation of China(22208137 and 22068022)Yunnan Fundamental Research Projects(202101BE070001-033,202401AT070825,202201BE070001007 and 202301AV070005)。
文摘Concurrent activation of lattice oxygen(O_L)and molecular oxygen(O_(2))is crucial for the efficient catalytic oxidation of biomass-derived molecules over metal oxides.Herein,we report that the introduction of ultralow-loading of Ru single atoms(0.42 wt%)into Mn_(2)O_(3)matrix(0.4%Ru-Mn_(2)O_(3))greatly boosts its catalytic activity for the aerobic oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA).The FDCA productivity over the 0.4%Ru-Mn_(2)O_(3)(5.4 mmol_(FDCA)g_(cat)h^(-1))is 4.9 times higher than the Mn_(2)O_(3).Especially,this FDCAproductivity is also significantly higher than that of existing Ru and Mn-based catalysts.Experimental and theoretical investigations discovered that the Ru single atom facilitated the formation of oxygen vacancy(O_(v))in the catalyst,which synergistically weakened the Mn-O bond and promoted the activation of O_L.The co-presence of Ru single atoms and O_(v)also promote the adsorption and activation of both O_(2)and HMF.Consequently,the dehydrogenation reaction energy barrier of the rate-determining step was reduced via both the O_L and chemisorbed O_(2)dehydrogenation pathways,thus boosting the catalytic oxidation reactions.
