Photocatalytic sacrificial H2 evolution dominated by micropore-confined exciton transfer in hydrogen-bonded organic frameworks

Abstract

<p>Organic semiconductors are attractive photocatalysts, but their quantum yields are limited by the transfer of photogenerated charges to the surface. A promising strategy for low-loss charge transfer is to shorten the distance from the bulk exciton coupling region to the catalyst surface. Here we employ the hydrogen-bonded organic framework 1,3,6,8-tetrakis(<em>p</em>-benzoic acid)pyrene (HOF-H₄TBAPy) with hydrophilic one-dimensional micropore channels as a proof of concept for this approach. Under irradiation, photogenerated excitons rapidly transfer to the inner surface of adjacent micropores, engendering a mere 1.88 nm transfer route, thus significantly improving exciton utilization. When the micropore channel length does not exceed 0.59 μm, the sacrificial photocatalytic H₂ evolution rate of HOF-H₄TBAPy reaches 358 mmol h⁻¹ g⁻¹ and the apparent quantum yield at 420 nm is 28.6%. We further demonstrated a stable 1.03 mol day⁻¹ m⁻² H₂ evolution on a 0.5 m² HOF-H₄TBAPy-loaded fibre under 1 Sun irradiation.<br></p>