LAUSR

Abstract Metal complexes have been one of the most promising photocatalysts for highly selective conversion of CO2 to carbon-based products. However, the aggregation-induced deactivation and narrow absorption range of sunlight impede their catalytic performance. Here, a heterogeneous photocatalytic system with a hydrazone-based covalent organic framework (COF) as photosensitizer and a metal complex [Ir-ppy] as photocatalyst is designed for efficient and durable photochemical CO2 reduction. Under visible-light irradiation, this heterogeneous system achieves CO yield of 88.6 μmol in 1 h’s reaction with the selectivity of 98%. This reactivity is 2.3 times higher than that of bare [Ir-ppy]. Significantly, comparing with the poor catalytic durability (30 min) of [Ir-ppy], the COF/[Ir-ppy] catalyst still be active after irradiation of 7 h. The extended catalytic reactivity may result from the promoting dispersion of [Ir-ppy] on NAHN-Tp COF which restrains the aggregation-induced deactivation of [Ir-ppy]. The enhanced reactivity may originate from the efficient electron transfer from COF to [Ir-ppy] and facilitated photo-induced charge separation as evidenced by matched band alignment of COF and [Ir-ppy], steady-state photoluminescence, time-resolved fluorescence.