Electrochemical measurements were carried out to elucidate decomposition mechanism of pentlandite using modified powder microelectrode with Acidithiobacillus ferrooxidans attached or without on the mineral powder surf...Electrochemical measurements were carried out to elucidate decomposition mechanism of pentlandite using modified powder microelectrode with Acidithiobacillus ferrooxidans attached or without on the mineral powder surface.Cyclic voltammetry（CV） results show that at a low potential of about-0.2 V（vs SCE）,the pentlandite was transformed to an intermediated phase like Fe4.5-yNi4.5-xS8-z when Fe and Ni ions were evacuated from mineral lattice;when the potential was changed from-0.2 V to 0.2 V,the unstable violarite（Fe3Ni3S4） and FeNi2S4 were formed which was accompanied by element sulfur formed on the mineral surface;when the potential increased over 0.2 V,the unstable intermediated phase decomposed entirely;at a higher potential of 0.7 V,the evacuated ferrous ion was oxidized to ferric ion.The presence of Acidithiobacillus ferrooxidans made the oxidation peak current increase with initial peak potential negatively moving,and the bacteria also contributed to the sulfur removing from mineral surface,which was demonstrated by the reduction characteristic at potential ranging from-0.75 to-0.5 V.Leaching experiments and electrochemical results show that the solution acidity increasing when pH2 may impede the oxidation process slightly.展开更多
Metal-rich transition metal sulfides recently gained increasing attention as electrocatalysts for the hydrogen evolution reaction(HER),as they are capable to overcome major challenges faced by sulfide-rich metal catal...Metal-rich transition metal sulfides recently gained increasing attention as electrocatalysts for the hydrogen evolution reaction(HER),as they are capable to overcome major challenges faced by sulfide-rich metal catalysts such as limited conductivity and the necessity of nanostructuring.Herein,we present the synthesis,characterization and electrocatalytic investigation of ternary metal-rich sulfide composites FexCo9-xS8 as well as Ni_(y)Co_(9-y)S_(8)(x=y=0-4.5),which possess pentlandite-type structures.In this study,we show a stepwise alteration of the binary cobalt pentlandite Co9S8 and report on the replacement of cobalt with up to 4.5 equivalents of either iron or nickel.These altered pentlandite composites facilitate the proton reduction in acidic media at different temperatures.We furthermore show that the stoichiometric variation has a decisive influence on the electrochemical activation/deactivation behavior of the catalysts under reductive electrocatalytic conditions.Here,Co-deficient composites display an improved HER performance in contrast to Co_(9)S_(8).Notably,Ni/Co compounds generally tend to show higher catalytic activities towards HER than their respective Fe/Co compounds.展开更多
Catalytic hydrogenation and hydrocracking of 9,10 diphenylanthracene (9,10 DPA) , used as a coal related model compound, was investigated at a relatively low temperature. The results show that the Fe and Ni mainly cat...Catalytic hydrogenation and hydrocracking of 9,10 diphenylanthracene (9,10 DPA) , used as a coal related model compound, was investigated at a relatively low temperature. The results show that the Fe and Ni mainly catalyze non ipso hydrogenation of 9,10 DPA without sulfur, but selectively promote ipso hydrogenation of 9,10 DPA in the presence of sulfur.展开更多
基金Project(20876014) supported by the National Natural Science Foundation of China
文摘Electrochemical measurements were carried out to elucidate decomposition mechanism of pentlandite using modified powder microelectrode with Acidithiobacillus ferrooxidans attached or without on the mineral powder surface.Cyclic voltammetry（CV） results show that at a low potential of about-0.2 V（vs SCE）,the pentlandite was transformed to an intermediated phase like Fe4.5-yNi4.5-xS8-z when Fe and Ni ions were evacuated from mineral lattice;when the potential was changed from-0.2 V to 0.2 V,the unstable violarite（Fe3Ni3S4） and FeNi2S4 were formed which was accompanied by element sulfur formed on the mineral surface;when the potential increased over 0.2 V,the unstable intermediated phase decomposed entirely;at a higher potential of 0.7 V,the evacuated ferrous ion was oxidized to ferric ion.The presence of Acidithiobacillus ferrooxidans made the oxidation peak current increase with initial peak potential negatively moving,and the bacteria also contributed to the sulfur removing from mineral surface,which was demonstrated by the reduction characteristic at potential ranging from-0.75 to-0.5 V.Leaching experiments and electrochemical results show that the solution acidity increasing when pH2 may impede the oxidation process slightly.
文摘Metal-rich transition metal sulfides recently gained increasing attention as electrocatalysts for the hydrogen evolution reaction(HER),as they are capable to overcome major challenges faced by sulfide-rich metal catalysts such as limited conductivity and the necessity of nanostructuring.Herein,we present the synthesis,characterization and electrocatalytic investigation of ternary metal-rich sulfide composites FexCo9-xS8 as well as Ni_(y)Co_(9-y)S_(8)(x=y=0-4.5),which possess pentlandite-type structures.In this study,we show a stepwise alteration of the binary cobalt pentlandite Co9S8 and report on the replacement of cobalt with up to 4.5 equivalents of either iron or nickel.These altered pentlandite composites facilitate the proton reduction in acidic media at different temperatures.We furthermore show that the stoichiometric variation has a decisive influence on the electrochemical activation/deactivation behavior of the catalysts under reductive electrocatalytic conditions.Here,Co-deficient composites display an improved HER performance in contrast to Co_(9)S_(8).Notably,Ni/Co compounds generally tend to show higher catalytic activities towards HER than their respective Fe/Co compounds.
文摘Catalytic hydrogenation and hydrocracking of 9,10 diphenylanthracene (9,10 DPA) , used as a coal related model compound, was investigated at a relatively low temperature. The results show that the Fe and Ni mainly catalyze non ipso hydrogenation of 9,10 DPA without sulfur, but selectively promote ipso hydrogenation of 9,10 DPA in the presence of sulfur.
