The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
The glucose isomerase(GI) was a metal activating enzyme It was most activated by Co 2+ and Mg 2+ ,and Mg 2+ was the best activator,whether the glucose or the xylose was the substrate When the glucose was substrate,the...The glucose isomerase(GI) was a metal activating enzyme It was most activated by Co 2+ and Mg 2+ ,and Mg 2+ was the best activator,whether the glucose or the xylose was the substrate When the glucose was substrate,the dissociation constant of Mg 2+ GI,Co 2+ GI and Mn 2+ -GI was 115 μmol/L,40 μmol/L, and 15 μmol/L respectively. The maximum activity of Mg 2+ GI,Co 2- GI and Mn 2+ GI was 100%,85%,and 20% respectively. When the xylose was substrate,the order of dissociation constant and maximum activity of the metal enzymes was the same Ca 2+ was a competitive inhibitor versus Mg 2+ ( K i 7 4 μmol/L)or Co 2+ ( K i 99 μmol/L). Compared with Mg 2+ GI,the K m of Co 2+ GI was more,and the V M of Co 2+ GI less The process of activity recovery from apo GI to metal GI showed that it was slow and of two展开更多
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
文摘The glucose isomerase(GI) was a metal activating enzyme It was most activated by Co 2+ and Mg 2+ ,and Mg 2+ was the best activator,whether the glucose or the xylose was the substrate When the glucose was substrate,the dissociation constant of Mg 2+ GI,Co 2+ GI and Mn 2+ -GI was 115 μmol/L,40 μmol/L, and 15 μmol/L respectively. The maximum activity of Mg 2+ GI,Co 2- GI and Mn 2+ GI was 100%,85%,and 20% respectively. When the xylose was substrate,the order of dissociation constant and maximum activity of the metal enzymes was the same Ca 2+ was a competitive inhibitor versus Mg 2+ ( K i 7 4 μmol/L)or Co 2+ ( K i 99 μmol/L). Compared with Mg 2+ GI,the K m of Co 2+ GI was more,and the V M of Co 2+ GI less The process of activity recovery from apo GI to metal GI showed that it was slow and of two
