Formic Acid Dehydrogenation for Hydrogen Production Promoted by Grubbs and Hoveyda‐Grubbs Catalysts †

Main observation and conclusion In this work, we screened three Grubbs catalysts and two Hoveyda‐Grubbs catalysts for the production of H 2 by dehydrogenation of formic acid (FA). The best results were achieved with the use of a first‐generation Hoveyda‐Grubbs catalyst. With a catalyst loading of mere 0.5 μmol, a maximum TON of 36356 was obtained within 3 h. Two key intermediates were identified by using 1 H NMR and high‐resolution electrospray ionization mass spectroscopy (HRESI‐MS), based on which a mechanism possibly responsible for the observed catalysis was proposed.