HCOOH can be selectively decomposed into CO free carbon dioxide and hydrogen.[1-3] It has
been shown, that beside the ruthenium(II)-mtppts systems,[4] the iron(II) – hydrido tris[(2-diphenylphosphino)
ethyl]-phosphine complex also catalyses formic acid cleavage with an exceptionally
high rate and efficiency.[5] Sustainable hydrogen storage[1, 6] have been developed based on the
hydrogenation of bicarbonates, or CO2.
Figure: Kinetics of formic acid dehydrogenation monitored by 13C NMR spectroscopy.
The water soluble ruthenium(II) – (mTPPTS) (mTPPTS= meta trisulphonated triphenylphosphine)
catalysts were immobilized in a hydrophilic silica support to facilitate mobile, portable
applications.[7] A series of heterogenized catalysts have been prepared using derivatized silica.
The length of the alkylene chain separating the silica from the diphenylphosphine group has been
varied in these catalysts, all of them catalyzing the decomposition of formic acid. The catalysts
were easily separated from the solution and reused. The optimized catalytic systems exhibited an
activity and stability comparable to the homogeneous catalysts.