Selective Formic Acid Decomposition for High‐Pressure Hydrogen Generation: A Mechanistic Study

Abstract A viable storage system for hydrogen based on selective formic acid decomposition into H 2 and CO 2 has been developed (see scheme). Continuous generation of H 2 of very high purity, over a wide range of pressures and under mild conditions was achieved. magnified image A homogenous catalytic system has been developed that efficiently and selectively decomposes formic acid into hydrogen and carbon dioxide. [Ru(H 2 O) 6 ] 2+ , [Ru(H 2 O) 6 ] 3+ and RuCl 3 ⋅ x H 2 O are all excellent pre‐catalysts in presence of TPPTS (TPPTS= meta ‐trisulfonated triphenylphosphine), the formic acid decomposition taking place in the aqueous phase, under mild conditions and over a large range of pressures. Optimisation of the reaction conditions is described together with a detailed mechanistic study leading to a tentative catalytic cycle. The performance of the catalytic system for continuous hydrogen generation is presented. Overall, the method proposed overcomes the limitations of other catalysts for the decomposition of formic acid making it a viable hydrogen‐storage material.