Nanosheet-Engineered NH2-MIL-125 with Highly Active Facets for Enhanced Solar CO2 Reduction

Rational engineering of metal–organic frameworks (MOFs) with maximum exposed highly active facets for photocatalytic CO2 reduction is desirable yet remains greatly challenging. Herein, ultrathin Ti-MOF NH2-MIL-125 nanosheets are successfully fabricated through a facile and efficient approach relying on the precursors directly. Importantly, the surfaces of the nanosheets are dominated by the {110} facet, which has more active sites than {001} and {111}. In contrast with conventional NH2-MIL-125 catalysts exposed with {001}, {110}, and {111} facets, the nanosheet material reported here exhibits remarkably high CO2 photoreduction performance through affording abundant active sites with augmented photoinduced electrons. The enhanced solar conversion CO2 activity of the ultrathin nanosheets is attributed to the favorable distribution of photoexcited electrons over all the Ti sites in the outer surface of the nanosheet, as revealed by density functional theory simulations.