用液相非稳态共沉淀法合成了Zn Al类水滑石(HTlc),研究了样品中n(Al)/n(Zn+Al)(x)和层间阴离子CO2-3对Zn Al HTlc化学组成、晶体结构和粒子形貌的影响。结果表明,当0 31≤x≤0 52时可得到单一的Zn Al Cl HTlc相;x≤0 25时有ZnO杂质相出...用液相非稳态共沉淀法合成了Zn Al类水滑石(HTlc),研究了样品中n(Al)/n(Zn+Al)(x)和层间阴离子CO2-3对Zn Al HTlc化学组成、晶体结构和粒子形貌的影响。结果表明,当0 31≤x≤0 52时可得到单一的Zn Al Cl HTlc相;x≤0 25时有ZnO杂质相出现;x>0 52时样品主要以无定形物存在。x对晶胞参数a和c影响不大;与Cl-相比,层间CO2-3对a影响不大,使c值略有降低。透射电镜(TEM)结果表明,随每摩尔HTlc样品n(Zn)增加,Zn Al ClHTlc粒子六角形片状结构规则度增加。电子衍射图谱表明,所合成的HTlc样品均为六方晶系多晶结构物质。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
A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and ...A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and morphology are confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) image. The d 001 of O-ZnAl-LDH is expanded to 2.85 nm after polymerization from 2.63 nm, which indicates the intercalation of PMA chains into the galleries of O-ZnAl-LDH. The (001) diffraction of PMA/ZnAl-LDH nanocomposite is broad due to the exfoliation of some O-ZnAl-LDH layers. The TEM image shows that the most of the layers of O-ZnAl-LDH are stacked with a distance of about 3 nm while some of them are exfoliated and dispersed disorderly in the PMA matrix.展开更多
Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double...Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double hydroxides （NiFe-LDHs） with specific interlayer anions （i.e. phosphate, phosphite, and hypophosphite） were fabricated by a co-predpitation method and investigated as oxygen evolution electrocatalysts. Intercalation of the phosphorus oxoanion enhanced the OER activity in an alkaline solution; the optimal performance （i.e., a low onset potential of 215 mV, a small Tafel slope of 37.7 mV/dec, and stable electrochemical behavior） was achieved with the hypophosphite-intercalated NiFe-LDH catalyst, demonstrating dramatic enhancement over the traditional carbonate-intercalated NiFe-LDH in terms of activity and durability. This enhanced performance is attributed to the interaction between the intercalated phosphorous oxoanions and the edge-sharing MO6 （M = Ni, Fe） layers, which modifies the surface electronic structure of the Ni sites. This concept should be inspiring for the design of more effective LDH-based oxygen evolution electrocatalvsts.展开更多
文摘用液相非稳态共沉淀法合成了Zn Al类水滑石(HTlc),研究了样品中n(Al)/n(Zn+Al)(x)和层间阴离子CO2-3对Zn Al HTlc化学组成、晶体结构和粒子形貌的影响。结果表明,当0 31≤x≤0 52时可得到单一的Zn Al Cl HTlc相;x≤0 25时有ZnO杂质相出现;x>0 52时样品主要以无定形物存在。x对晶胞参数a和c影响不大;与Cl-相比,层间CO2-3对a影响不大,使c值略有降低。透射电镜(TEM)结果表明,随每摩尔HTlc样品n(Zn)增加,Zn Al ClHTlc粒子六角形片状结构规则度增加。电子衍射图谱表明,所合成的HTlc样品均为六方晶系多晶结构物质。
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.
文摘A poly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH). Its structure and morphology are confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) image. The d 001 of O-ZnAl-LDH is expanded to 2.85 nm after polymerization from 2.63 nm, which indicates the intercalation of PMA chains into the galleries of O-ZnAl-LDH. The (001) diffraction of PMA/ZnAl-LDH nanocomposite is broad due to the exfoliation of some O-ZnAl-LDH layers. The TEM image shows that the most of the layers of O-ZnAl-LDH are stacked with a distance of about 3 nm while some of them are exfoliated and dispersed disorderly in the PMA matrix.
文摘Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double hydroxides （NiFe-LDHs） with specific interlayer anions （i.e. phosphate, phosphite, and hypophosphite） were fabricated by a co-predpitation method and investigated as oxygen evolution electrocatalysts. Intercalation of the phosphorus oxoanion enhanced the OER activity in an alkaline solution; the optimal performance （i.e., a low onset potential of 215 mV, a small Tafel slope of 37.7 mV/dec, and stable electrochemical behavior） was achieved with the hypophosphite-intercalated NiFe-LDH catalyst, demonstrating dramatic enhancement over the traditional carbonate-intercalated NiFe-LDH in terms of activity and durability. This enhanced performance is attributed to the interaction between the intercalated phosphorous oxoanions and the edge-sharing MO6 （M = Ni, Fe） layers, which modifies the surface electronic structure of the Ni sites. This concept should be inspiring for the design of more effective LDH-based oxygen evolution electrocatalvsts.
