AI Article Synopsis
- A nickel(II) porphyrin (Ni-P) with enhanced solubility and activity was studied for hydrogen-evolution reactions (HER), demonstrating its effectiveness in producing H2 from acetic acid and trifluoroacetic acid (TFA).
- Doubly reduced Ni-P ([Ni-P](2-)) was effective in H2 production from acetic acid, while the singly reduced species ([Ni-P](-)) showed better initiation of HER with TFA.
- The research indicates that a hydride species ([H-Ni-P]) forms through oxidative protonation, suggesting a unique catalytic cycle that could inform future designs for more efficient H2 generation methods.
Article Abstract
A nickel(II) porphyrin Ni-P (P=porphyrin) bearing four meso-C6 F5 groups to improve solubility and activity was used to explore different hydrogen-evolution-reaction (HER) mechanisms. Doubly reduced Ni-P ([Ni-P](2-) ) was involved in H2 production from acetic acid, whereas a singly reduced species ([Ni-P](-) ) initiated HER with stronger trifluoroacetic acid (TFA). High activity and stability of Ni-P were observed in catalysis, with a remarkable ic /ip value of 77 with TFA at a scan rate of 100 mV s(-1) and 20 °C. Electrochemical, stopped-flow, and theoretical studies indicated that a hydride species [H-Ni-P] is formed by oxidative protonation of [Ni-P](-) . Subsequent rapid bimetallic homolysis to give H2 and Ni-P is probably involved in the catalytic cycle. HER cycling through this one-electron-reduction and homolysis mechanism has been proposed previously but rarely validated. The present results could thus have broad implications for the design of new exquisite cycles for H2 generation.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5071703 | PMC |
| http://dx.doi.org/10.1002/anie.201510001 | DOI Listing |
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