Molecular Compartments Created in Metal-Organic Frameworks for Efficient Visible-Light-Driven CO2 Overall Conversion

We report the construction of molecular compartments by the growth of narrow-band semiconductor nanoparticles, tungsten oxide and its hydrate, in the mesopores of a metalorganic framework (MOF), MIL-100-Fe. The location of these nanoparticles in pores and their spatial arrangement across the MOF crystal are unveiled by powder X-ray diffraction and smallangle neutron scattering, respectively. Such a composition with pore-level precision leads to efficient overall conversion of gasphase CO2 and H2O to CO, CH4, and H2O2 under visible light. When WO3 center dot H2O nanoparticles are positioned in 2.5 nm mesopores with 24 wt %, the resulting composite, namely, 24%WO3 center dot H2O-in-MIL-100-Fe, exhibits a CO2 reduction rate of 0.49 mmol center dot g(-1)center dot h(-1) beyond 420 nm and an apparent quantum efficiency of 1.5% at 420 nm. These performances stand as new benchmarks for visible-light-driven CO2 overall conversion. In addition to the size and location of semiconductor nanoparticles, the coordinated water species in the crystal are found critical for high catalytic activity, an aspect usually overlooked.