1. Impaired conjugation boosts CO2 electroreduction by Ni(ii) macrocyclic catalysts immobilized on carbon nanotubes
- Author
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Huang, Y., Dai, H., Moonshiram, Dooshaye, Li, Z., Luo, Z.-M., Zhang, J.-H., Yang, W., Shen, Y., Wang, J.-W., Ouyang, G., Huang, Y., Dai, H., Moonshiram, Dooshaye, Li, Z., Luo, Z.-M., Zhang, J.-H., Yang, W., Shen, Y., Wang, J.-W., and Ouyang, G.
- Abstract
Metal complexes hybridized with conductive supports are desirable as high-performance catalysts for CO2 electroreduction, while the delicate molecular design to improve both the intrinsic activity of complex and the molecule-support interactions still remains challenging. We here employ a conjugation-tuning strategy by comparison between Ni(ii) octabutoxyphthalocyanine and Ni(ii) octabutoxynaphthalocyanine on multi-walled carbon nanotubes (NiPc-B@CNT and NiNc-B@CNT) in aqueous electrocatalytic CO2 reduction, respectively. In contrast to the conventional promotive effects from extended conjugation, the impaired conjugation in the Ni(ii) macrocycles unusually boosts both activity and molecule-support affinity. These merits can be attributed to the favored electronic effects and the higher flexibility of long alkyl chains both arising from the absent extended benzene ring in NiPc-B. Consequently, NiPc-B@CNT exhibits much higher faradaic efficiencies for CO production (FECO ≥ 94% among −0.79 to −1.09 V vs. RHE) than NiNc-B@CNT (FECO < 20%) in an H-cell configuration. The use of a gas-diffusion electrode further raises the electrocatalytic performances of NiPc-B@CNT under 1 atm CO2 (FECO ≈ 100% at −0.15 A cm−2) or simulated flue gas (10% CO2, FECO ≈ 80% at −0.1 A cm−2), respectively. © 2023 The Royal Society of Chemistry.
- Published
- 2023