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Shu-zhong Zhan - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical-driven water splitting catalyzed by a water-soluble cobalt(II) complex supported by N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
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electrochemical driven water splitting catalyzed by a water soluble cobalt ii complex supported by n n bis 2 pyridinecarboxamide 1 2 benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
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electrochemical driven hydrogen evolution from acetic acid and water catalyzed by a mixed valent coii coi complex with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Jie-ping Cao, Ling-ling Zhou, Shu-zhong ZhanAbstract:Abstract The reaction of 2,3-bis(2-hydroxybenzylideneimino)-2,3-butenedinitrile (H 2 L1) and CoCl 2 ·6H 2 O affords a mixed-valent dinuclear Co II –Co I complex [Co I L(py) 3 ][Co II L 2 ] 1 (L = 2-(2-hydroxybenzylideneimino)-butenedinitrile ion), a new molecular electrocatalyst, which has been determined by X-ray crystallography and XPS spectrum. Electrochemical studies indicate that the catalyst is the first Co II –Co I complex species, that is among the most rapid homogeneous water-reduction catalysts, with a Turnover Frequency (TOF) of 2387 mol of hydrogen per mole of catalyst per hour at an overpotential of 787 mV vs SHE (pH 7.0). Sustained proton reduction catalysis occurs at glassy carbon (GC) to give H 2 over a 46 h electrolysis period with 97% Faradaic yield and no observable decomposition of the catalyst.
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Electrochemical-driven hydrogen evolution from acetic acid and water catalyzed by a mixed-valent CoII–CoI complex with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Jie-ping Cao, Ling-ling Zhou, Shu-zhong ZhanAbstract:Abstract The reaction of 2,3-bis(2-hydroxybenzylideneimino)-2,3-butenedinitrile (H 2 L1) and CoCl 2 ·6H 2 O affords a mixed-valent dinuclear Co II –Co I complex [Co I L(py) 3 ][Co II L 2 ] 1 (L = 2-(2-hydroxybenzylideneimino)-butenedinitrile ion), a new molecular electrocatalyst, which has been determined by X-ray crystallography and XPS spectrum. Electrochemical studies indicate that the catalyst is the first Co II –Co I complex species, that is among the most rapid homogeneous water-reduction catalysts, with a Turnover Frequency (TOF) of 2387 mol of hydrogen per mole of catalyst per hour at an overpotential of 787 mV vs SHE (pH 7.0). Sustained proton reduction catalysis occurs at glassy carbon (GC) to give H 2 over a 46 h electrolysis period with 97% Faradaic yield and no observable decomposition of the catalyst.
Jianshan Ye - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical-driven water splitting catalyzed by a water-soluble cobalt(II) complex supported by N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
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electrochemical driven water splitting catalyzed by a water soluble cobalt ii complex supported by n n bis 2 pyridinecarboxamide 1 2 benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
Erling Rytter - One of the best experts on this subject based on the ideXlab platform.
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effect of biomass derived synthesis gas impurity elements on cobalt fischer tropsch catalyst performance including in situ sulphur and nitrogen addition
Journal of Catalysis, 2011Co-Authors: Øyvind Borg, Rune Myrstad, Torild Hulsund Skagseth, Nina Hammer, Bjorn Christian Enger, O A Lindvag, Sigrid Eri, Erling RytterAbstract:Abstract The effect of 10 typical biomass-derived synthesis gas impurities on cobalt Fischer–Tropsch catalyst performance was investigated at industrially relevant conditions. Impurities (0–1000 ppmw) were introduced ex situ by incipient wetness impregnation to give 23 different compositions. The presence of alkali (Na, K) and alkaline earth elements (Ca, Mg) did not affect the ex situ -measured cobalt surface area but decreased the in situ activity, thereby decreasing the apparent Turnover Frequency. The C 5+ selectivity increased and decreased upon addition of alkali and alkaline earth metals, respectively. Mn, Fe, and P had minor effects on catalyst performance. The presence of Cl decreased cobalt surface without affecting activity, thus increasing the Turnover Frequency. The changes in Turnover Frequency correlated with element electronegativity. In situ addition of H 2 S and (CH 3 ) 2 S (2.5–10 ppm) decreased activity at all concentrations. However, product selectivity was not affected. Addition of NH 3 (4 ppm) did not change catalytic performance.
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Effect of biomass-derived synthesis gas impurity elements on cobalt Fischer–Tropsch catalyst performance including in situ sulphur and nitrogen addition
Journal of Catalysis, 2011Co-Authors: Øyvind Borg, Rune Myrstad, Torild Hulsund Skagseth, Nina Hammer, Bjorn Christian Enger, O A Lindvag, Sigrid Eri, Erling RytterAbstract:Abstract The effect of 10 typical biomass-derived synthesis gas impurities on cobalt Fischer–Tropsch catalyst performance was investigated at industrially relevant conditions. Impurities (0–1000 ppmw) were introduced ex situ by incipient wetness impregnation to give 23 different compositions. The presence of alkali (Na, K) and alkaline earth elements (Ca, Mg) did not affect the ex situ -measured cobalt surface area but decreased the in situ activity, thereby decreasing the apparent Turnover Frequency. The C 5+ selectivity increased and decreased upon addition of alkali and alkaline earth metals, respectively. Mn, Fe, and P had minor effects on catalyst performance. The presence of Cl decreased cobalt surface without affecting activity, thus increasing the Turnover Frequency. The changes in Turnover Frequency correlated with element electronegativity. In situ addition of H 2 S and (CH 3 ) 2 S (2.5–10 ppm) decreased activity at all concentrations. However, product selectivity was not affected. Addition of NH 3 (4 ppm) did not change catalytic performance.
Giuliano Moretti - One of the best experts on this subject based on the ideXlab platform.
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Turnover Frequency for NO decomposition over Cu-ZSM-5 catalysts: insight into the reaction mechanism
Catalysis Letters, 1994Co-Authors: Giuliano MorettiAbstract:In this letter we present a simple model useful to understand the relationship between the Turnover Frequency for NO decomposition over Cu-ZSM-5 catalysts ( N _Cu), the number of Al atoms per unit cell of the ZSM-5 zeolite ( p ), and the copper loading expressed as percent of exchange ( E ). Our simple model is able to explain the literature data. We show that: (1) on catalysts with the highest activity (Cu exchange levels E >90%), N _Cu increases with p (i.e. decreasing the Si/A1 ratio) indicating that the most active sites may contain two close copper ions; (2) at low Cu exchange levels ( E
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Turnover Frequency for no decomposition over cu zsm 5 catalysts insight into the reaction mechanism
Catalysis Letters, 1994Co-Authors: Giuliano MorettiAbstract:In this letter we present a simple model useful to understand the relationship between the Turnover Frequency for NO decomposition over Cu-ZSM-5 catalysts (NCu), the number of Al atoms per unit cell of the ZSM-5 zeolite (p),and the copper loading expressed as percent of exchange (E). Our simple model is able to explain the literature data. We show that: (1) on catalysts with the highest activity (Cu exchange levelsE>90%),NCu increases withp (i.e. decreasing the Si/A1 ratio) indicating that the most active sites may contain two close copper ions; (2) at low Cu exchange levels (E<80%) the catalysts have lower activity and, moreover,NCu decreases withP, according to previous results of Iwamoto et al. (1986). The present results are also in agreement with the evidence that the redox couple Cu2–/Cu– play a key role in the reaction mechanism.
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Effects of the Si/Al atomic ratio on the activity of Cu-ZSM-5 catalysts for nitric oxide decomposition
Catalysis Letters, 1994Co-Authors: Giuliano MorettiAbstract:A review of literature data for nitric oxide decomposition over Cu-ZSM-5 catalysts leads us to conclude that the Turnover Frequency depends on the Si/Al atomic ratio in a way opposite to the trend suggested by Iwamoto and co-workers and considered correct by Shelef in a recent letter published in this Journal. In particular we show that the Turnover Frequency increases with the number of Al atoms per unit cell (i.e. decreasing the Si/Al atomic ratio). This result suggests that the most active sites for NO decomposition over Cu-ZSM-5 catalysts may contain two close copper ions.
Zhuo-qiang Wang - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical-driven water splitting catalyzed by a water-soluble cobalt(II) complex supported by N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
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electrochemical driven water splitting catalyzed by a water soluble cobalt ii complex supported by n n bis 2 pyridinecarboxamide 1 2 benzene with high Turnover Frequency
Journal of Power Sources, 2015Co-Authors: Zhuo-qiang Wang, Shu-zhong Zhan, Ling-zhi Tang, Yun-xiao Zhang, Jianshan YeAbstract:Abstract The oxidation and reduction of water is a key challenge in the production of chemical fuels from electricity. Reported here is a soluble cobalt (II) complex, [Co(bpbH 2 )Cl 2 ] 1 (bpbH 2 : N,N′-bis(2′-pyridinecarboxamide)-1,2-benzene), a highly active homogeneous electrocatalyst for both electrolytic water oxidation and reduction in purely aqueous solution. Electrochemical studies indicate that the catalyst is a water-soluble molecular species, that is among the most rapid homogeneous catalysts for water oxidation, with a Turnover Frequency of ∼81.54 s −1 (at pH 8.6, the lowest pH among those of any reported electrocatalysts) at an overpotential of 560 mV. 1 also can catalyze hydrogen evolution from water with a TOF of 376 mol of hydrogen per mole of catalyst per hour at an overpotential of 687.6 mV (pH 7.0). This is attributed to the planar ligand (bpbH 2 ), that coordinates strongly through four nitrogen atoms to the cobalt center, leaving two Cl − ions in axial position and making the Cl − ion ionize in organic solvents or water, and can stabilize both the high and low oxidation states of cobalt well.
