Natural magnetite formed by the isomorphism substitutions of transition metals,including Fe,Ti,Co,etc.,was activated by mechanical grinding followed by H2 reduction.The temperature-programmed reduction of hydrogen(H2-...Natural magnetite formed by the isomorphism substitutions of transition metals,including Fe,Ti,Co,etc.,was activated by mechanical grinding followed by H2 reduction.The temperature-programmed reduction of hydrogen(H2-TPR)and temperature-programmed surface reaction of carbon dioxide(CO2-TPSR)were carried out to investigate the processes of oxygen loss and CO2 reduction.The samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM),and energy-dispersive X-ray spectroscopy(EDS).The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H2 atmosphere.Meanwhile,the activity and selectivity of CO2 reduction into carbon were enhanced.The deposited carbon on the activated natural magnetite was confirmed as amorphous.The amount of carbon after CO2 reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt%higher than that over the natural magnetite.展开更多
One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron sourc...One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide.The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis.The Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2016YFB 0600904).The authors gratefully acknowledge the support of the Analytical and Test Center of Sichuan University.
文摘Natural magnetite formed by the isomorphism substitutions of transition metals,including Fe,Ti,Co,etc.,was activated by mechanical grinding followed by H2 reduction.The temperature-programmed reduction of hydrogen(H2-TPR)and temperature-programmed surface reaction of carbon dioxide(CO2-TPSR)were carried out to investigate the processes of oxygen loss and CO2 reduction.The samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM),and energy-dispersive X-ray spectroscopy(EDS).The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H2 atmosphere.Meanwhile,the activity and selectivity of CO2 reduction into carbon were enhanced.The deposited carbon on the activated natural magnetite was confirmed as amorphous.The amount of carbon after CO2 reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt%higher than that over the natural magnetite.
基金supported by the National Natural Science Foundation of China(No.51876046 and No.51711540032)。
文摘One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide.The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis.The Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.
