posted on 2021-05-05, 10:14authored byMing-Feng Qin, Qiao-Qiao Mu, Song-Song Bao, Xu Liang, Yang Peng, Li-Min Zheng
In
this paper, we report the first example of semiconducting porphyrinylphosphonate
metal–organic framework (MOF) [Co(Ni-H7TPPP)2]·8H2O and its chemical exfoliation into ultrathin
metal–organic layers (MOLs) with an electric conductivity up
to 0.12 S cm–1 at RT. Benefiting from the 2D layered
structure possessing highly accessible metalloporphyrin-active motifs,
a negatively charged surface, and a phosphonate-enhanced structural
stability, the exfoliated MOL enables the material to behave as an
efficient cocatalyst in coordination with positively charged [Ru(bpy)3]2+ to photocatalytically reduce CO2 to CO in a high yield rate (3.16 × 104 μmol
g–1 h–1) and selectivity (81%).
Spectroscopic studies engaging DRS, UPS, PL, EIS, and TPR unanimously
point to the remarkable photocatalytic performance being a result
of proper band alignment among the system components and great charge
extraction capability of the cocatalyst. More importantly, by explicitly
dissecting the band structure and charge transport behavior, this
study provides insights into catalyst design to afford a coherent
energy flow in hybrid photocatalytic systems.