Simple Iron Ion Enables Photocatalytic Hydrogen Evolution from Methanol

We report the discovery of a remarkably simple homogeneous catalyst – iron (Fe) ion –that conducts hydrogen gas (H2) evolution from methanol under ultraviolet (UV) light irradiation. Unlike previously reported homogeneous organometallic catalysts for methanol dehydrogenation, our system functions without synthetic ligands and is conceptually distinct from general heterogeneous and photoredox catalysts. The Fe ion catalysis achieved a turnover frequency (TOF) of 149 h–1 and a production rate of 9.21 × 102 mmol gcat–1 h–1 for methanol dehydrogenation with input of UV light (250–385 nm, 30 mW). These values place the Fe ion catalyst within the upper performance range of previously reported systems – including homogeneous, heterogeneous, and photoredox catalysts comprising both precious and non-precious metals. The Fe catalytic system is not limited to lower alcohols; it can also be applied to biomass and its derivatives. This simple and effective catalytic system, discovered serendipitously, has no documented analogs, to the best of our knowledge.