Noble-Metal-Free Photocatalyst System via BODIPY-Based MOFs for Highly Efficient Visible-Light-Driven H2 Evolution†
Developing noble-metal-free photocatalyst system via metal–organic frameworks (MOFs) is very imperative and demanding. In this contribution, by employing pyridine-functionalized boron dipyrromethene (BODIPY) linker both as the light-harvesting antenna and organic struts in the presence of 4,4'-biphenyldicarboxylic acid (H2BPDC) or 4,4'-sulfonyldibenzoic acid (H2SDB) , two MOFs [Cd2(BODIPY)2(BPDC)2] (denoted as CCNU-11, CCNU= Central China Normal University) and [Cd2(BODIPY)2(SDB)2] (CCNU-12) with the identical topology structure can be reliably synthesized, featuring the same redox levels. In the presence of tris(bipyridine)cobalt ([Co(bpy)3]Cl2), CCNU-11 holds excellent photocatalytic activity of 60.4 mmol/g/h whereas that for CCNU-12 is 44.6 mmol/g/h under visible illumination (λ > 420 nm) with the use of triethylamine (TEA) as a sacrificial reagent. These remarkable values are among the highest ones reported thus far for MOFs with proton reduction co-catalysts. Moreover, the higher photocatalytic efficiency over CCNU-11+[Co(bpy)3]Cl2 probably benefit from the pore characteristics within CCNU-11. This work provides fundamental insight into the role of porosity in photocatalytic performance and is likely to inform ongoing efforts to exploit noble-metal-free photocatalytic systems via BODIPY-based MOFs for highly efficient and long-term solar fuels production.