1. Impact of oxidation state of metal on electro-catalyzed hydrogen production by cobalt complexes of N-phenylpyridin-2-ylmethanimine.
- Author
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Wang, Nan-Shu, Zhan, Jun-Zheng, Liu, Ze-Quan, Cao, Qian-Qian, Wang, Chun-Li, and Zhan, Shu-Zhong
- Subjects
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HYDROGEN production , *HYDROGEN content of metals , *OXIDATION states , *COBALT , *HYDROGEN evolution reactions , *ACETIC acid , *POTENTIOMETRY , *ELECTROCATALYSTS - Abstract
N-phenylpyridin-2-ylmethanimine, L, reacts with CoCl2·6H2O to form a water soluble complex, [CoIII(L)2Cl2]Cl, which has been determined by X-ray diffraction analysis. Electrochemical studies show that [CoIII(L)2Cl2]Cl can serve as an electrocatalyst for water or proton reduction to hydrogen from neutral water (pH 7.0) or acetic acid with a turnover frequency (TOF) of 1032.4 and 70.3 moles of hydrogen per mole of catalyst per hour (mol H2/mol catalyst/h) at an overpotential (OP) of 837.6 mV and 941.6 mV, respectively. Compared with the previously described cobalt(II) complex, [CoII(L)2Br2] (TOF: 875.17 mol H2/mol catalyst/h at an OP of 837.6 mV), the cobalt(III) complex, [CoIII(L)2Cl2]Cl exhibits more efficient activity for hydrogen evolution. This can be attributed to CoIII/CoII and CoII/CoI couples of [CoIII(L)2Cl2]Cl are responsible for hydrogen production. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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