Rational Design of Improved Ru Containing Fe‐Based Metal‐Organic Framework (MOF) Photoanode for Artificial Photosynthesis

Abstract

Metal‐Organic Frameworks (MOFs) recently emerged as a new platform for the realization of integrated devices for artificial photosynthesis. However, there remain few demonstrations of rational tuning of such devices for improved performance. Here, a fast molecular water oxidation catalyst working via water nucleophilic attack is integrated into the MOF MIL‐142, wherein Fe3O nodes absorb visible light, leading to charge separation. Materials are characterized by a range of structural and spectroscopic techniques. New, [Ru(tpy)(Qc)(H2O)]+ (tpy = 2,2′:6′,2″‐terpyridine and Qc = 8‐quinolinecarboxylate)‐doped Fe MIL‐142 achieved a high photocurrent (1.6 × 10−3 A·cm−2) in photo‐electrocatalytic water splitting at pH = 1. Unassisted photocatalytic H2 evolution is also reported with Pt as the co‐catalyst (4.8 µmol g−1 min−1). The high activity of this new system enables hydrogen gas capture from an easy‐to‐manufacture, scaled‐up prototype utilizing MOF deposited on FTO glass as a photoanode. These findings provide insights for the development of MOF‐based light‐driven water‐splitting assemblies utilizing a minimal amount of precious metals and Fe‐based photosensitizers.