Bromo- and iodo-bridged building units in metal-organic frameworks for enhanced carrier transport and CO2 photoreduction by water vapor

Abstract

Organolead halide hybrids have many promising attributes for photocatalysis, e.g. tunable bandgaps and excellent carrier transport, but their instability constraints render them vulnerable to polar molecules and limit their photocatalysis in moisture. Herein, we report the construction of metal–organic frameworks based on [Pb2X]3+ (X = Br–/I–) chains as secondary building units and 2-amino-terephthalate as organic linkers, and extend their applications in photocatalytic CO2 reduction with water vapor as the reductant. Hall effect measurement and ultrafast transient absorption spectroscopy demonstrate the bromo/iodo-bridged frameworks have substantially enhanced photocarrier transport, which results in photocatalytic performances superior to conventional metal-oxo metal-organic frameworks. Moreover, in contrast to lead perovskites, the [Pb2X]3+-based frameworks have accessible porosity and high moisture stability for gas-phase photocatalytic reaction between CO2 and H2O. This work significantly advances the excellent carrier transport of lead perovskites into the field of metal-organic frameworks.