Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(...Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.展开更多
A series of metal-Al_(2)O_(3)catalysts were prepared simply by the conventional impregnation with Al_(2)O_(3)and metal chlorides,which were applied to the dehydration of fructose to 5-hydroxymethylfurfural(HMF).An agr...A series of metal-Al_(2)O_(3)catalysts were prepared simply by the conventional impregnation with Al_(2)O_(3)and metal chlorides,which were applied to the dehydration of fructose to 5-hydroxymethylfurfural(HMF).An agreeable HMF yield of 93.1%was achieved from fructose at mild conditions(100℃and 40 min)when employing Cr(III)-Al_(2)O_(3)as catalyst in 1-butyl-3-methylimidazolium chloride([Bmim]Cl).The Cr(III)-Al_(2)O_(3)catalyst was characterized via XRD,DRS and Raman spectra and the results clarified the interaction between the Cr(III)and the alumina support.Meanwhile,the reaction solvents([Bmim]Cl)collected after 1st reaction run and 5th reaction run were analyzed by ICP-OES and LC-ITMS and the results confirmed that no Cr(III)ion was dropped off from the alumina support dur-ing the fructose dehydration.Notably,Cr(III)-Al_(2)O_(3)catalyst had an excellent catalytic performance for glucose and sucrose and the HMF yields were reached to 73.7%and 84.1%at 120℃for 60 min,respectively.Furthermore,the system of Cr(III)-Al_(2)O_(3)and[Bmim]Cl exhibited a constant stability and activity at 100℃for 40 min and a fa-vorable HMF yield was maintained after ten recycles.展开更多
基金support from the National Natural Science Foundation of China(51402100,21905088,21573066 and U19A2017)the Provincial Natural Science Foundation of Hunan(2020JJ5044,2022JJ10006)。
文摘Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.
基金The authors thank the financial support for this study by the National Natural Science Foundation of China(Nos.21106057 and 21376111)Society Devel-opment Fund of Zhenjiang(SH2012009)Advanced Talents of Jiangsu University(10JDG143).
文摘A series of metal-Al_(2)O_(3)catalysts were prepared simply by the conventional impregnation with Al_(2)O_(3)and metal chlorides,which were applied to the dehydration of fructose to 5-hydroxymethylfurfural(HMF).An agreeable HMF yield of 93.1%was achieved from fructose at mild conditions(100℃and 40 min)when employing Cr(III)-Al_(2)O_(3)as catalyst in 1-butyl-3-methylimidazolium chloride([Bmim]Cl).The Cr(III)-Al_(2)O_(3)catalyst was characterized via XRD,DRS and Raman spectra and the results clarified the interaction between the Cr(III)and the alumina support.Meanwhile,the reaction solvents([Bmim]Cl)collected after 1st reaction run and 5th reaction run were analyzed by ICP-OES and LC-ITMS and the results confirmed that no Cr(III)ion was dropped off from the alumina support dur-ing the fructose dehydration.Notably,Cr(III)-Al_(2)O_(3)catalyst had an excellent catalytic performance for glucose and sucrose and the HMF yields were reached to 73.7%and 84.1%at 120℃for 60 min,respectively.Furthermore,the system of Cr(III)-Al_(2)O_(3)and[Bmim]Cl exhibited a constant stability and activity at 100℃for 40 min and a fa-vorable HMF yield was maintained after ten recycles.
