Seawater electrolysis holds great promise for sustainable green hydrogen production,but it is challenged by chloride-induced corrosion.Herein,we demonstrate the hydrothermal preparation of Pb-doped NiFe layered double...Seawater electrolysis holds great promise for sustainable green hydrogen production,but it is challenged by chloride-induced corrosion.Herein,we demonstrate the hydrothermal preparation of Pb-doped NiFe layered double hydroxide on Ni foam(Pb-NiFe LDH/NF)for alkaline seawater oxidation electrocatalysis.Our Pb-NiFe LDH/NF requires a low overpotential of only 381 mV to attain a current density of 1000 mA·cm^(-2),superior to its NiFe LDH/NF counterpart(423 mV).Additionally,it operates continuously for 1000 h with negligible performance degradation and minimal active chlorine production.In situ Raman spectroscopy analysis reveals that Pb incorporation facilitates catalyst surface reconstruction,thereby enhancing oxygen evolution reaction activity.Importantly,Pb selectively adsorbs free Cl^(-)to form stable Pb-Cl species under the influence of an applied electric field.This process creates a Cl^(-)-free layer near the anode surface,thereby enhancing the catalyst’s chlorine corrosion resistance.展开更多
Cryptomelane is a reactive Mn oxide and has been used in removal of heavy metal from wastewaters. Co-doped cryptomelane was synthesized by refluxing at ambient pressure and characterized by powder X-ray diffraction, s...Cryptomelane is a reactive Mn oxide and has been used in removal of heavy metal from wastewaters. Co-doped cryptomelane was synthesized by refluxing at ambient pressure and characterized by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and extended X-ray absorption fine structure spectroscopy, and its performances for removal of Pb^2＋ and Cr^3＋ from aqueous solutions were investigated. Co doping has a negligible effect on the structure and morphology of cryptomelane but increases the specific surface area and Mn average oxidation state. Mn and Co K-edge extended X-ray absorption fine structure spectroscopy（EXAFS） analysis shows that Co barely affects the atomic coordination environments of Mn, and distances of edge- and corner-sharing Co–Me（Me_Co, Mn） pairs are shorter than those of the corresponding Mn–Me pairs, implying the replacement of framework Mn（III） by Co（III）. These Co-doped cryptomelanes can quickly oxidize Cr3＋to be HCr O4-and remove 45%–66% of the total Cr in the reaction systems by adsorption and fixation, and they have enhanced Pb2＋adsorption capacities. Thus these materials are promising adsorbents for heavy metal remediation. The results demonstrate the design and modification of environmental friendly Mn oxide materials and can help us understand the interaction mechanisms of transition metals with Mn oxides.展开更多
基金funding this work through Large Research Project under Grant(No.RGP2/28/46).
文摘Seawater electrolysis holds great promise for sustainable green hydrogen production,but it is challenged by chloride-induced corrosion.Herein,we demonstrate the hydrothermal preparation of Pb-doped NiFe layered double hydroxide on Ni foam(Pb-NiFe LDH/NF)for alkaline seawater oxidation electrocatalysis.Our Pb-NiFe LDH/NF requires a low overpotential of only 381 mV to attain a current density of 1000 mA·cm^(-2),superior to its NiFe LDH/NF counterpart(423 mV).Additionally,it operates continuously for 1000 h with negligible performance degradation and minimal active chlorine production.In situ Raman spectroscopy analysis reveals that Pb incorporation facilitates catalyst surface reconstruction,thereby enhancing oxygen evolution reaction activity.Importantly,Pb selectively adsorbs free Cl^(-)to form stable Pb-Cl species under the influence of an applied electric field.This process creates a Cl^(-)-free layer near the anode surface,thereby enhancing the catalyst’s chlorine corrosion resistance.
基金supported by the National Natural Science Foundation of China (Nos.41271253 and 41401250)the Huazhong Agricultural University Doctoral Start-up Fund (Grant 52902-0900206162)
文摘Cryptomelane is a reactive Mn oxide and has been used in removal of heavy metal from wastewaters. Co-doped cryptomelane was synthesized by refluxing at ambient pressure and characterized by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and extended X-ray absorption fine structure spectroscopy, and its performances for removal of Pb^2＋ and Cr^3＋ from aqueous solutions were investigated. Co doping has a negligible effect on the structure and morphology of cryptomelane but increases the specific surface area and Mn average oxidation state. Mn and Co K-edge extended X-ray absorption fine structure spectroscopy（EXAFS） analysis shows that Co barely affects the atomic coordination environments of Mn, and distances of edge- and corner-sharing Co–Me（Me_Co, Mn） pairs are shorter than those of the corresponding Mn–Me pairs, implying the replacement of framework Mn（III） by Co（III）. These Co-doped cryptomelanes can quickly oxidize Cr3＋to be HCr O4-and remove 45%–66% of the total Cr in the reaction systems by adsorption and fixation, and they have enhanced Pb2＋adsorption capacities. Thus these materials are promising adsorbents for heavy metal remediation. The results demonstrate the design and modification of environmental friendly Mn oxide materials and can help us understand the interaction mechanisms of transition metals with Mn oxides.
