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
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
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 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
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.
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 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(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.
