Co–Mo catalysts applied on the hydrodesulfurization（HDS） for FCC gasoline were prepared with Zn–Al layered double hydroxides（LDHs） to improve their performances,and the effects of pore structures and acidity on ...Co–Mo catalysts applied on the hydrodesulfurization（HDS） for FCC gasoline were prepared with Zn–Al layered double hydroxides（LDHs） to improve their performances,and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn–Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH-,CO2-,Al3＋,and Zn2＋. The neutralization p H is a main factor to affect the pore structures and acidity of Zn–Al/LDHs,and a series of Zn–Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas（SBET） and acidities,three Co Mo/LDHs catalysts were prepared,and their HDS performances were compared with traditional Co Mo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBETpossessed high HDS activity,and Br？nsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than Co Mo/Al2O3,and could restrain the reactions of re-combination between olefin and H2 S which could be due to the existence of Br？nsted acid sites.展开更多
In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]...In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.展开更多
Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffracti...Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffraction.Compound 1（C10H14O8） crystallizes in the triclinic system,space group P1 with a = 6.3751（6）,b = 8.5311（8）,c = 11.4510（11）A,α = 93.3650（10）,β = 105.3190（10）,γ = 97.2140（10）°,V = 593.15（10） A^3,Z = 2,Mr = 262.21,Dc = 1.468 g/cm^3,F（000） = 276,GOOF = 1.005,° = 0.129 mm^-1,the final R = 0.0361 and w R = 0.0802 for 1854 observed reflections with I 〉 2σ（I）.Compound 2（C30H28N2O12） crystallizes in the triclinic system,space group P1 with a = 9.7416（13）,b = 11.839（2）,c = 12.9828（13） A,α = 74.191（4）,β = 77.953（2）,γ = 74.726（3）°,V = 1374.5（3） A^3,Z = 2,Mr = 608.54,Dc = 1.470 g/cm^3,F（000） = 636,GOOF = 1.061,° = 0.115 mm^-1,the final R = 0.0500 and w R = 0.1221 for 3966 observed reflections with I 〉 2σ（I）.Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions.The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria（S.aureus,C.albicans and B.subtilis） and gram negative bacteria（E.coli and P.aeruginosa）.展开更多
NiFe(oxy)hydroxide(NiFeOOH)has been widely studied as a catalyst for oxygen evolution reaction(OER),but its activity is still not satisfactory.Although metal doping has been employed as a promising strategy for addres...NiFe(oxy)hydroxide(NiFeOOH)has been widely studied as a catalyst for oxygen evolution reaction(OER),but its activity is still not satisfactory.Although metal doping has been employed as a promising strategy for addressing this issue,the instability and leaching of the high-valence dopant metals remain considerable challenges.Herein,an array of Cr-doped NiFeOOH nanosheets was in situ synthesized on nickel foam via a one-step hydrothermal method.The doping of NiFeOOH with Cr was found to induce partial electron transfer from Ni and Fe to Cr atoms,thereby modulating the electronic structure of the catalyst and enhancing its intrinsic activity.Electrochemical and in situ Raman spectroscopy analyses showed that Fe active sites with lower charge density enhance the adsorption of^(*) OH and reduce the formation energy barrier of the*OOH intermediate during OER,thereby accelerating the OER.Moreover,Fe was found to promote the transfer of additional electrons to Cr,leading to electron accumulation at Cr sites.This electron accumulation effectively prevents Cr from excessive oxidation and leaching under anode potentials,thereby maintaining the structural stability of the catalyst.The optimized Cr-doped NiFeOOH self-supported electrode exhibited a current density of 50 mA/cm^(2) with an overpotential of only 239 mV and remained stable for 100 h at 600 mA/cm^(2) in 1 mol/L KOH.展开更多
Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demo...Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.展开更多
Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral ...Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral spheres electrocatalyst was constructed on nickel foam(NF)via an interfacial engineering strategy.This 3D core-shell heterostructure maximizes the exposure of active sites,optimizes the charge transport pathway and accelerates gas release rates.The protective shell strategy of NiFe LDH provides favorable stability,which contributes to inhibiting the electrochemical corrosion of the electrocatalyst and mitigating the toxic effects of Cl−and other microorganisms during the seawater splitting process.Moreover,the introduction of NiFe LDH induces a change in the OER mechanism from an adsorption evolution mechanism(AEM)to a lattice oxygen mechanism(LOM),which improves the intrinsic activity of the catalyst.Consequently,Co_(3)S_(4)/CuS@NiFe LDH demonstrates exceptional performance in the oxygen evolution reaction(OER)(η100=251 mV)and in the hydrogen evolution reaction(HER)(η100=254 mV),alongside remarkable stability over 100 h.For OWS,it exhibits a voltage of 1.46 V at 10 mA/cm^(2) and maintain stability for 100 h.Impressively,Co_(3)S_(4)/CuS@NiFe LDH still possesses outstanding activity and stability in natural alkaline seawater.This work proposes interfacial engineering to construct bifunctional catalysts with core-shell heterostructures,providing instructive guidelines for the design of highly efficient electrocatalysts toward seawater electrolysis.展开更多
The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water sp...The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides（LDHs） and their derivatives（e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides） have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.展开更多
Coke powder is expected to be an excellent raw material to produce activated carbon because of its high carbon content. Potassium hydroxide(KOH), as an effective activation agent, was reported to be effective in activ...Coke powder is expected to be an excellent raw material to produce activated carbon because of its high carbon content. Potassium hydroxide(KOH), as an effective activation agent, was reported to be effective in activating coke powder. However, the microstructures development in the coke powder and its mechanisms when KOH was applied were still unclear. In this study, effects of KOH on the microstructure activation of coke powder were investigated using the surface area and pore structure analyzer, scanning electron microscope(SEM) and thermogravimetry-differential scanning calorimetry-mass spectrometry(TG-DSC-MS), etc. Results revealed that the addition KOH at its lower ratio(mass ratios of KOH and coke powder in a range of 0.5 and 1) decreased the specific surface area and average lateral sizes, but sharply increased of the specific surface area to 132 m^2·g^-1 and 355 m^2·g^-1 and decreased of the space size of aromatic crystallites upon the further increase of the KOH addition amounts(ratios of KOH and coke powder in a range of 3 and 7), generating a number of new micropores and mesopores. The mechanisms study implied surface reactions between KOH and aliphatic hydrocarbon side chain and other carbon functional groups of the coke powder to destruct aromatic crystallites in one dimension and broaden pores at lower KOH addition. In the activation process, KOH was decomposed to be more active components, which can be rapidly destruct the aromatic layers in spatial scope to form developed porous carbon structures within coke powder at higher KOH addition.展开更多
NiFe(oxy)hydroxides nanosheets were synthesized on nickel foams via co-precipitation and electrochemical activation. It is found that the phosphate precursors(Na_(3)PO_(4), Na_(2)HPO_(4)and NaH_(2)PO_(4)) have diverse...NiFe(oxy)hydroxides nanosheets were synthesized on nickel foams via co-precipitation and electrochemical activation. It is found that the phosphate precursors(Na_(3)PO_(4), Na_(2)HPO_(4)and NaH_(2)PO_(4)) have diverse effects on the morphology and thus the oxygen evolution reaction activity of the formed final catalysts. The resulting NiFe(oxy)hydroxides nanosheets prepared with Na_(2)HPO_(4)demonstrate a low overpotential of 205 m V to achieve a current density of 50 mA/cm^(2) with a Tafel slope down to 30 mV/dec in 1 mol/L KOH, and remain stable for 20 h during stability test.展开更多
The electrodeposition approach is significant in electrode fabrication for practical application.Herein,the electrodeposited amorphous NiFe hydroxide species for oxygen evolution reaction (OER) in water splitting reac...The electrodeposition approach is significant in electrode fabrication for practical application.Herein,the electrodeposited amorphous NiFe hydroxide species for oxygen evolution reaction (OER) in water splitting reaction is demonstrated by revealing the synergistic effect influenced by the support electrode of Fe and Ni foil and the contents of Fe and Ni in the electrolyte.All the electrodeposited samples have an amorphous structure and similar profiles of binding energy and chemical states for Fe and Ni as characterized by the spectroscopic techniques.While the support effect and Fe/Ni synergistic effect are indeed observed for the varied catalytic performances observed for the different electrodes;the Ni foil supported catalyst exhibits much higher performance than that of the Fe foil supported catalyst,and the different redox potentials of Ni species in the different Fe/Ni electrode resulting from the Fe–Ni synergism are observed in the cyclic voltammetry curve analysis.The surface roughness and the electrochemical surface area are also influenced by the support effect and the Fe/Ni ratio in the plating electrolyte.The optimal electrode shows a very low overpotential of~200 mV to reach 10 mA cm^(-2),and very high catalytic stability by the consecutive cyclic voltammetry measurements and 20 h stability test.Though it has the largest electrochemical surface area,the highest catalytic efficiency for these active sites is also indicated by the specific activity and turnover frequency polarization curves.The current work shows the effective experience for the electrodeposited Fe/Ni based catalysts in large-scale fabrication,which can be more practical for hydrogen generation in the alkaline water electrolysis.展开更多
The properties of layered double hydroxides(LDHs),including the adjustability of cations in host layers,exchangeability of anions between layers,and tunability of the crystal structure,render them unique characteristi...The properties of layered double hydroxides(LDHs),including the adjustability of cations in host layers,exchangeability of anions between layers,and tunability of the crystal structure,render them unique characteristics in preparation and applications.Relating to the structural characteristics of LDHs,this work analyzes the research status,advantages and disadvantages of the synthetic methods for LDHs,including hydrothermal,electrodeposition,co-precipitation and anion exchange methods.In addition,the application status and prospects are reviewed,such as photo/electrocatalysis,electrochemical energy storage,magnetic materials,pollutant adsorption,and other fields.Lastly,the critical issues and solutions in the developing process of LDHs are analyzed and proposed.展开更多
Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporat...Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporated nickel iron(oxy)hydroxide(S-NiFeOOH)nanosheets were directly grown on commercial nickel foam using a galvanic corrosion method and a hydrothermal method.The incorporation of sulfur into NiFeOOH enhanced the catalytic activity for the HER and OER in 1 M KOH electrolyte.The enhanced catalytic activity is attributed to the change in the local structure and chemical states due to the incorporation of sulfur.High performance for overall water splitting was achieved with an alkaline water electrolyzer.This was realized by employing S-NiFeOOH as a bifunctional electrocatalyst,thereby outperforming a water electrolyzer that requires the usage of precious metal electrocatalysts(i.e.,Pt/C as the HER electrocatalyst and IrO_(2) as the OER electrocatalyst).Moreover,when driven by a commercial silicon solar cell,an alkaline water electrolyzer that uses S-NiFeOOH as a bifunctional electrocatalyst generated hydrogen under natural illumination.This study shows that S-NiFeOOH is a promising candidate for a large-scale industrial implementation of hydrogen production for overall water splitting because of its low cost,high activity,and durability.In addition,the solar-driven water electrolyzer using S-NiFeOOH as a bifunctional electrocatalyst affords the opportunity for developing effective and feasible solar power systems in the future.展开更多
The title compound N-（（3-（2-nitrophenyl） propanoyl）oxy）-N-phenylbenzamide（C22H18N2O5,Mr = 390.38） was synthesized with nitrobenzene as the starting materials and structurally characterized by 1H NMR,13 C NMR,I...The title compound N-（（3-（2-nitrophenyl） propanoyl）oxy）-N-phenylbenzamide（C22H18N2O5,Mr = 390.38） was synthesized with nitrobenzene as the starting materials and structurally characterized by 1H NMR,13 C NMR,IR,H RMS（E-SI） and single-crystal X-ray diffraction.The crystalline structure of the title compound was studied in detail.The single-crystal X-ray diffraction revealed that the compound crystallizes in monoclinic,space group P21/n,with a = 14.4481（7）,b = 8.0089（5）,c = 16.6808（9） A,α = 90.00（5）,β = 100.069（5）,γ = 90.00（5）°,Mr = 390.38,V = 1900.46（18） A^3,Z = 4,Dc = 1.364 g/cm^-3,μ = 0.098,F（000） = 816.0,the final R = 0.0530 and w R = 0.1141 for 2525 observed reflections（I 〉 2σ（I））,R（all data） = 0.0813,w R（all data） = 0.1335,completeness to theta of 26.020 is 99.8% and GOF = 1.085.The crystal structure contains three branched chains with its center placed at the midpoint of N.The phenyl ring（C（8）~C（13）） makes a dihedral angle of 83.5（1） ℃ with the phenyl ring（C（1）~C（6））,and 80.5（1） ℃with the nitro-substituted benzene ring（C（17）~C（22））,indicating that the three rings are not coplanar.Hydrogen bonds（C（10）–H（10）···O（3））,（C（15）–H（15B）···O（4） and C（16）–H（16B）···O（4）） together with π-π stacking interactions stabilize the structure of the molecule.The preliminary biological test shows that the title compound has good antitumor activity against A549 in vitro with the IC50 value of 3.17 μmol.展开更多
To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on it...To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an adsorbent.Results displayed high I^-saturation uptake capability(137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH(26.4 mg/g) even thermal activated LDH(76.1 mg/g).Thermodynamic analysis showed that the reaction between I^-anions and Cu/Cu2O-LDH is a spontaneous and exothermic.Uptake kinetics analysis exhibited that adsorption equilibrium can be reached after 265 min.Additionally, the adsorbent showed satisfactory selectivity in the presence of competitive anions(e.g., SO4^2-), and could achieve good adsorption performance in a wide pH range of 3–8.A cooperative adsorption mechanism was proposed on the basis of the following two aspects:(1) ion exchange between iodide and interlayer anions;(2) the adsorption performance of Cu, Cu(Ⅱ) and Cu2O for I^-.Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.展开更多
Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the...Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the preparation of structured NiFe catalysts on washcoated cordierite monoliths for CO_(2) methanation.The NiFe catalysts were derived from in-situ grown layered double hydroxides(LDHs)via urea hydrolysis.The influence of different washcoat materials,i.e.,alumina and silica colloidal suspensions on the formation of LDHs layer was investigated,together with the impact of total metal concentration.NiFe LDHs were precipitated on the exterior surface of cordierite washcoated with alumina,while it was found to deposit further inside the channel wall of monolith washcoated with silica due to different intrinsic properties of the colloidal solutions.On the other hand,the thickness of in-situ grown LDHs layers and the catalyst loading could be increased by high metal concentration.The best monolithic catalyst(COR-AluCC-0.5M)was robust,having a thin and well-adhered catalytic layer on the cordierite substrate.As a result,high methane yield was obtained from CO_(2) methanation at high flow rate on this structured NiFe catalysts.The monolithic catalysts appeared as promising structured catalysts for the development of industrial methanation reactor.展开更多
Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites ...Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites of bulk LDHs increase the internal resistance and reduce the capacity and oxygen-production efficiency of electrodes.Herein,we prepared a polyaniline-coated Ni-Co-layered double hydroxide intercalated with MoO_(4)^(2−)(M-LDH@PANI)composite electrode using a two-step method.As the amount of MoO_(4)^(2−)in the LDH increases,acicular microspheres steadily evolve into flaky microspheres with a high surface area,providing more active electrochemical sites.Moreover,the amorphous PANI coating of M-LDH boosts the electronic conductivity of the composite electrode.Accordingly,the M-LDH@PANI at an appropriate level of MoO_(4)^(2−)exhibits significantly enhanced energy storage and catalytic performance.Experimental analyses and theoretical calculations reveal that a small amount of MoO_(4)^(2−)is conducive to the expansion of LDH interlayer spacing,while an excessive amount of MoO_(4)^(2−)combines with the H atoms of LDH,thus competing with OH^(−),resulting in reduced electrochemical performance.Moreover,M-LDH flaky microspheres can efficiently modulate deprotonation energy,greatly accelerating surface redox reactions.This study provides an explanation for an unconventional mechanism,and a method for the modification of LDH-based materials for anion intercalation.展开更多
To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on ele...To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.展开更多
Corrosion engineering is an effective way to improve the oxygen evolution reaction(OER)activity of al-loys.However,the impact of grain boundary corrosion on the structure and electrochemical performance of alloy is st...Corrosion engineering is an effective way to improve the oxygen evolution reaction(OER)activity of al-loys.However,the impact of grain boundary corrosion on the structure and electrochemical performance of alloy is still unknown.Herein,the vacuum arc-melted CrCoNiFe alloys with interlaced network struc-tures via grain boundary corrosion methods were fabricated.The grain boundaries that existed as de-fects were severely corroded and an interlaced network structure was formed,promoting the exposure of the active site and the release of gas bubbles.Besides,the(oxy)hydroxides layer(25 nm)on the sur-face could act as the true active center and improve the surface wettability.Benefiting from the unique structure and constructed surface,the CrCoNiFe-12 affords a high urea oxidation reaction(UOR)perfor-mance with the lowest overpotential of 250 mV at 10 mA/cm^(2)in 1 M KOH adding 0.33 M urea.The CrCoNiFe-12||Pt only required a cell voltage of 1.485 V to afford 10 mA/cm^(2)for UOR and long-term sta-bility of 100 h at 10 mA/cm^(2)(27.6 mV decrease).These findings offer a facile strategy for designing bulk multiple-principal-element alloy electrodes for energy conversion.展开更多
The aggregation and fractal structure of mixed metal hydroxides ( MMH ) agglomerates with increasing ionic strength have been studied by dynamic light scattering ( DLS ) and SEM techniques. The experiments indicate th...The aggregation and fractal structure of mixed metal hydroxides ( MMH ) agglomerates with increasing ionic strength have been studied by dynamic light scattering ( DLS ) and SEM techniques. The experiments indicate that the MMH agglomerates have two different structures in RLA regime and DLA regime, and also give the proof that the transition region between RLA and DLA may occur.展开更多
文摘Co–Mo catalysts applied on the hydrodesulfurization（HDS） for FCC gasoline were prepared with Zn–Al layered double hydroxides（LDHs） to improve their performances,and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn–Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH-,CO2-,Al3＋,and Zn2＋. The neutralization p H is a main factor to affect the pore structures and acidity of Zn–Al/LDHs,and a series of Zn–Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas（SBET） and acidities,three Co Mo/LDHs catalysts were prepared,and their HDS performances were compared with traditional Co Mo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBETpossessed high HDS activity,and Br？nsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than Co Mo/Al2O3,and could restrain the reactions of re-combination between olefin and H2 S which could be due to the existence of Br？nsted acid sites.
基金supported by the National Natural Science Foundation of China(51502078)the Major Project of Science and Technology,Education Department of Henan Province(19A150019 and 19A150018)+2 种基金the Science and Technology Research Project of Henan Province(192102310490 and 182102410090)the program for Science&Technology Innovation Team in Universities of Henan Province(19IRTSTHN029)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,and Biosciences Division,Catalysis Science program。
文摘In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.
基金Supported by the National Natural Science Foundation of China(No.21264011,20961007)the Aviation Fund(No.2014ZF56020)
文摘Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffraction.Compound 1（C10H14O8） crystallizes in the triclinic system,space group P1 with a = 6.3751（6）,b = 8.5311（8）,c = 11.4510（11）A,α = 93.3650（10）,β = 105.3190（10）,γ = 97.2140（10）°,V = 593.15（10） A^3,Z = 2,Mr = 262.21,Dc = 1.468 g/cm^3,F（000） = 276,GOOF = 1.005,° = 0.129 mm^-1,the final R = 0.0361 and w R = 0.0802 for 1854 observed reflections with I 〉 2σ（I）.Compound 2（C30H28N2O12） crystallizes in the triclinic system,space group P1 with a = 9.7416（13）,b = 11.839（2）,c = 12.9828（13） A,α = 74.191（4）,β = 77.953（2）,γ = 74.726（3）°,V = 1374.5（3） A^3,Z = 2,Mr = 608.54,Dc = 1.470 g/cm^3,F（000） = 636,GOOF = 1.061,° = 0.115 mm^-1,the final R = 0.0500 and w R = 0.1221 for 3966 observed reflections with I 〉 2σ（I）.Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions.The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria（S.aureus,C.albicans and B.subtilis） and gram negative bacteria（E.coli and P.aeruginosa）.
基金supported by the National Natural Science Foundation of China(Nos.51822106 and 52002318).
文摘NiFe(oxy)hydroxide(NiFeOOH)has been widely studied as a catalyst for oxygen evolution reaction(OER),but its activity is still not satisfactory.Although metal doping has been employed as a promising strategy for addressing this issue,the instability and leaching of the high-valence dopant metals remain considerable challenges.Herein,an array of Cr-doped NiFeOOH nanosheets was in situ synthesized on nickel foam via a one-step hydrothermal method.The doping of NiFeOOH with Cr was found to induce partial electron transfer from Ni and Fe to Cr atoms,thereby modulating the electronic structure of the catalyst and enhancing its intrinsic activity.Electrochemical and in situ Raman spectroscopy analyses showed that Fe active sites with lower charge density enhance the adsorption of^(*) OH and reduce the formation energy barrier of the*OOH intermediate during OER,thereby accelerating the OER.Moreover,Fe was found to promote the transfer of additional electrons to Cr,leading to electron accumulation at Cr sites.This electron accumulation effectively prevents Cr from excessive oxidation and leaching under anode potentials,thereby maintaining the structural stability of the catalyst.The optimized Cr-doped NiFeOOH self-supported electrode exhibited a current density of 50 mA/cm^(2) with an overpotential of only 239 mV and remained stable for 100 h at 600 mA/cm^(2) in 1 mol/L KOH.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(No.12034002)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities,No.FRF-IDRY-23-033)。
文摘Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.
基金supported by the National Natural Science Foundation of China(No.52274304).
文摘Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral spheres electrocatalyst was constructed on nickel foam(NF)via an interfacial engineering strategy.This 3D core-shell heterostructure maximizes the exposure of active sites,optimizes the charge transport pathway and accelerates gas release rates.The protective shell strategy of NiFe LDH provides favorable stability,which contributes to inhibiting the electrochemical corrosion of the electrocatalyst and mitigating the toxic effects of Cl−and other microorganisms during the seawater splitting process.Moreover,the introduction of NiFe LDH induces a change in the OER mechanism from an adsorption evolution mechanism(AEM)to a lattice oxygen mechanism(LOM),which improves the intrinsic activity of the catalyst.Consequently,Co_(3)S_(4)/CuS@NiFe LDH demonstrates exceptional performance in the oxygen evolution reaction(OER)(η100=251 mV)and in the hydrogen evolution reaction(HER)(η100=254 mV),alongside remarkable stability over 100 h.For OWS,it exhibits a voltage of 1.46 V at 10 mA/cm^(2) and maintain stability for 100 h.Impressively,Co_(3)S_(4)/CuS@NiFe LDH still possesses outstanding activity and stability in natural alkaline seawater.This work proposes interfacial engineering to construct bifunctional catalysts with core-shell heterostructures,providing instructive guidelines for the design of highly efficient electrocatalysts toward seawater electrolysis.
基金supported by the National Natural Science Foundation of China(Nos.U146211821601011)+2 种基金the 973 Program(Grant No.2014CB932102)the Fundamental Research Funds for the Central Universities(buctrc201506PYCC1704)
文摘The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides（LDHs） and their derivatives（e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides） have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.
基金Supported by the National Key R&D Plan(2016YFE0131100,2017YFB0603101)the Program for Sanjin Scholars of Shanxi Provincethe Talent Training Program of Shanxi Joint Postgraduate Training Base(2016JD07).
文摘Coke powder is expected to be an excellent raw material to produce activated carbon because of its high carbon content. Potassium hydroxide(KOH), as an effective activation agent, was reported to be effective in activating coke powder. However, the microstructures development in the coke powder and its mechanisms when KOH was applied were still unclear. In this study, effects of KOH on the microstructure activation of coke powder were investigated using the surface area and pore structure analyzer, scanning electron microscope(SEM) and thermogravimetry-differential scanning calorimetry-mass spectrometry(TG-DSC-MS), etc. Results revealed that the addition KOH at its lower ratio(mass ratios of KOH and coke powder in a range of 0.5 and 1) decreased the specific surface area and average lateral sizes, but sharply increased of the specific surface area to 132 m^2·g^-1 and 355 m^2·g^-1 and decreased of the space size of aromatic crystallites upon the further increase of the KOH addition amounts(ratios of KOH and coke powder in a range of 3 and 7), generating a number of new micropores and mesopores. The mechanisms study implied surface reactions between KOH and aliphatic hydrocarbon side chain and other carbon functional groups of the coke powder to destruct aromatic crystallites in one dimension and broaden pores at lower KOH addition. In the activation process, KOH was decomposed to be more active components, which can be rapidly destruct the aromatic layers in spatial scope to form developed porous carbon structures within coke powder at higher KOH addition.
基金supported by the National Natural Science Foundation of China (Nos. 11904411, 52072308)the Fundamental Research Funds for the Central Universities, China (Nos. 3102021MS0404, 3102019JC001)。
文摘NiFe(oxy)hydroxides nanosheets were synthesized on nickel foams via co-precipitation and electrochemical activation. It is found that the phosphate precursors(Na_(3)PO_(4), Na_(2)HPO_(4)and NaH_(2)PO_(4)) have diverse effects on the morphology and thus the oxygen evolution reaction activity of the formed final catalysts. The resulting NiFe(oxy)hydroxides nanosheets prepared with Na_(2)HPO_(4)demonstrate a low overpotential of 205 m V to achieve a current density of 50 mA/cm^(2) with a Tafel slope down to 30 mV/dec in 1 mol/L KOH, and remain stable for 20 h during stability test.
基金supported by the National Natural Science Foundation of China (21972124, U2002213)the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University (2019FY003025)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionthe financial support of national local joint engineering laboratory to functional adsorption material technology for the environmental protection, Soochow University (SDGC2124)。
文摘The electrodeposition approach is significant in electrode fabrication for practical application.Herein,the electrodeposited amorphous NiFe hydroxide species for oxygen evolution reaction (OER) in water splitting reaction is demonstrated by revealing the synergistic effect influenced by the support electrode of Fe and Ni foil and the contents of Fe and Ni in the electrolyte.All the electrodeposited samples have an amorphous structure and similar profiles of binding energy and chemical states for Fe and Ni as characterized by the spectroscopic techniques.While the support effect and Fe/Ni synergistic effect are indeed observed for the varied catalytic performances observed for the different electrodes;the Ni foil supported catalyst exhibits much higher performance than that of the Fe foil supported catalyst,and the different redox potentials of Ni species in the different Fe/Ni electrode resulting from the Fe–Ni synergism are observed in the cyclic voltammetry curve analysis.The surface roughness and the electrochemical surface area are also influenced by the support effect and the Fe/Ni ratio in the plating electrolyte.The optimal electrode shows a very low overpotential of~200 mV to reach 10 mA cm^(-2),and very high catalytic stability by the consecutive cyclic voltammetry measurements and 20 h stability test.Though it has the largest electrochemical surface area,the highest catalytic efficiency for these active sites is also indicated by the specific activity and turnover frequency polarization curves.The current work shows the effective experience for the electrodeposited Fe/Ni based catalysts in large-scale fabrication,which can be more practical for hydrogen generation in the alkaline water electrolysis.
基金financially supported by National Natural Science Foundation of China(No.52102100)Industry-University-Research Cooperation Project of Jiangsu Province(No.BY2021525)Key Research and Development Program(Social Development)of Zhenjiang City(No.SH2019009)。
文摘The properties of layered double hydroxides(LDHs),including the adjustability of cations in host layers,exchangeability of anions between layers,and tunability of the crystal structure,render them unique characteristics in preparation and applications.Relating to the structural characteristics of LDHs,this work analyzes the research status,advantages and disadvantages of the synthetic methods for LDHs,including hydrothermal,electrodeposition,co-precipitation and anion exchange methods.In addition,the application status and prospects are reviewed,such as photo/electrocatalysis,electrochemical energy storage,magnetic materials,pollutant adsorption,and other fields.Lastly,the critical issues and solutions in the developing process of LDHs are analyzed and proposed.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.NRF-2016R1D1A3B04935101).
文摘Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporated nickel iron(oxy)hydroxide(S-NiFeOOH)nanosheets were directly grown on commercial nickel foam using a galvanic corrosion method and a hydrothermal method.The incorporation of sulfur into NiFeOOH enhanced the catalytic activity for the HER and OER in 1 M KOH electrolyte.The enhanced catalytic activity is attributed to the change in the local structure and chemical states due to the incorporation of sulfur.High performance for overall water splitting was achieved with an alkaline water electrolyzer.This was realized by employing S-NiFeOOH as a bifunctional electrocatalyst,thereby outperforming a water electrolyzer that requires the usage of precious metal electrocatalysts(i.e.,Pt/C as the HER electrocatalyst and IrO_(2) as the OER electrocatalyst).Moreover,when driven by a commercial silicon solar cell,an alkaline water electrolyzer that uses S-NiFeOOH as a bifunctional electrocatalyst generated hydrogen under natural illumination.This study shows that S-NiFeOOH is a promising candidate for a large-scale industrial implementation of hydrogen production for overall water splitting because of its low cost,high activity,and durability.In addition,the solar-driven water electrolyzer using S-NiFeOOH as a bifunctional electrocatalyst affords the opportunity for developing effective and feasible solar power systems in the future.
基金Supported by the Lanzhou Science and Technology Bureau Program Funds(2013-4-79,2014-1-174,2014-1-214)
文摘The title compound N-（（3-（2-nitrophenyl） propanoyl）oxy）-N-phenylbenzamide（C22H18N2O5,Mr = 390.38） was synthesized with nitrobenzene as the starting materials and structurally characterized by 1H NMR,13 C NMR,IR,H RMS（E-SI） and single-crystal X-ray diffraction.The crystalline structure of the title compound was studied in detail.The single-crystal X-ray diffraction revealed that the compound crystallizes in monoclinic,space group P21/n,with a = 14.4481（7）,b = 8.0089（5）,c = 16.6808（9） A,α = 90.00（5）,β = 100.069（5）,γ = 90.00（5）°,Mr = 390.38,V = 1900.46（18） A^3,Z = 4,Dc = 1.364 g/cm^-3,μ = 0.098,F（000） = 816.0,the final R = 0.0530 and w R = 0.1141 for 2525 observed reflections（I 〉 2σ（I））,R（all data） = 0.0813,w R（all data） = 0.1335,completeness to theta of 26.020 is 99.8% and GOF = 1.085.The crystal structure contains three branched chains with its center placed at the midpoint of N.The phenyl ring（C（8）~C（13）） makes a dihedral angle of 83.5（1） ℃ with the phenyl ring（C（1）~C（6））,and 80.5（1） ℃with the nitro-substituted benzene ring（C（17）~C（22））,indicating that the three rings are not coplanar.Hydrogen bonds（C（10）–H（10）···O（3））,（C（15）–H（15B）···O（4） and C（16）–H（16B）···O（4）） together with π-π stacking interactions stabilize the structure of the molecule.The preliminary biological test shows that the title compound has good antitumor activity against A549 in vitro with the IC50 value of 3.17 μmol.
基金supported by the National Natural Science Foundation of China(Nos.11805101 and 11205089)the Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials(No.KFK1504)the Environmental Protection Research Project of Jiangsu Province(No.JSZC-D2018-044).
文摘To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an adsorbent.Results displayed high I^-saturation uptake capability(137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH(26.4 mg/g) even thermal activated LDH(76.1 mg/g).Thermodynamic analysis showed that the reaction between I^-anions and Cu/Cu2O-LDH is a spontaneous and exothermic.Uptake kinetics analysis exhibited that adsorption equilibrium can be reached after 265 min.Additionally, the adsorbent showed satisfactory selectivity in the presence of competitive anions(e.g., SO4^2-), and could achieve good adsorption performance in a wide pH range of 3–8.A cooperative adsorption mechanism was proposed on the basis of the following two aspects:(1) ion exchange between iodide and interlayer anions;(2) the adsorption performance of Cu, Cu(Ⅱ) and Cu2O for I^-.Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.
文摘Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the preparation of structured NiFe catalysts on washcoated cordierite monoliths for CO_(2) methanation.The NiFe catalysts were derived from in-situ grown layered double hydroxides(LDHs)via urea hydrolysis.The influence of different washcoat materials,i.e.,alumina and silica colloidal suspensions on the formation of LDHs layer was investigated,together with the impact of total metal concentration.NiFe LDHs were precipitated on the exterior surface of cordierite washcoated with alumina,while it was found to deposit further inside the channel wall of monolith washcoated with silica due to different intrinsic properties of the colloidal solutions.On the other hand,the thickness of in-situ grown LDHs layers and the catalyst loading could be increased by high metal concentration.The best monolithic catalyst(COR-AluCC-0.5M)was robust,having a thin and well-adhered catalytic layer on the cordierite substrate.As a result,high methane yield was obtained from CO_(2) methanation at high flow rate on this structured NiFe catalysts.The monolithic catalysts appeared as promising structured catalysts for the development of industrial methanation reactor.
文摘Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites of bulk LDHs increase the internal resistance and reduce the capacity and oxygen-production efficiency of electrodes.Herein,we prepared a polyaniline-coated Ni-Co-layered double hydroxide intercalated with MoO_(4)^(2−)(M-LDH@PANI)composite electrode using a two-step method.As the amount of MoO_(4)^(2−)in the LDH increases,acicular microspheres steadily evolve into flaky microspheres with a high surface area,providing more active electrochemical sites.Moreover,the amorphous PANI coating of M-LDH boosts the electronic conductivity of the composite electrode.Accordingly,the M-LDH@PANI at an appropriate level of MoO_(4)^(2−)exhibits significantly enhanced energy storage and catalytic performance.Experimental analyses and theoretical calculations reveal that a small amount of MoO_(4)^(2−)is conducive to the expansion of LDH interlayer spacing,while an excessive amount of MoO_(4)^(2−)combines with the H atoms of LDH,thus competing with OH^(−),resulting in reduced electrochemical performance.Moreover,M-LDH flaky microspheres can efficiently modulate deprotonation energy,greatly accelerating surface redox reactions.This study provides an explanation for an unconventional mechanism,and a method for the modification of LDH-based materials for anion intercalation.
基金the National Natural Science Foundation of China(NSFC Grant No.62174152).
文摘To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.
基金supported by the National Natu-ral Science Foundation of China(No.52102210)the Natural Sci-ence Foundation of Sichuan Province(Nos.2022NSFSC2005 and 2022NSFSC1255)+1 种基金the Opening Project of Key Laboratory of Op-toelectronic Chemical Materials and Devices of Ministry of Educa-tion,Jianghan University(No.JDGD-202218)Supplementary materials Supplementary material associated with this article can be found,in the online version,at doi:10.1016/j.jmst.2024.01.096.106。
文摘Corrosion engineering is an effective way to improve the oxygen evolution reaction(OER)activity of al-loys.However,the impact of grain boundary corrosion on the structure and electrochemical performance of alloy is still unknown.Herein,the vacuum arc-melted CrCoNiFe alloys with interlaced network struc-tures via grain boundary corrosion methods were fabricated.The grain boundaries that existed as de-fects were severely corroded and an interlaced network structure was formed,promoting the exposure of the active site and the release of gas bubbles.Besides,the(oxy)hydroxides layer(25 nm)on the sur-face could act as the true active center and improve the surface wettability.Benefiting from the unique structure and constructed surface,the CrCoNiFe-12 affords a high urea oxidation reaction(UOR)perfor-mance with the lowest overpotential of 250 mV at 10 mA/cm^(2)in 1 M KOH adding 0.33 M urea.The CrCoNiFe-12||Pt only required a cell voltage of 1.485 V to afford 10 mA/cm^(2)for UOR and long-term sta-bility of 100 h at 10 mA/cm^(2)(27.6 mV decrease).These findings offer a facile strategy for designing bulk multiple-principal-element alloy electrodes for energy conversion.
基金supported by the National Natural Science Foundation of China(No.20273041)the Ministry of the Education.
文摘The aggregation and fractal structure of mixed metal hydroxides ( MMH ) agglomerates with increasing ionic strength have been studied by dynamic light scattering ( DLS ) and SEM techniques. The experiments indicate that the MMH agglomerates have two different structures in RLA regime and DLA regime, and also give the proof that the transition region between RLA and DLA may occur.
