Hydrogen Production from Formic Acid Decomposition Promoted by Gold Nanoparticles Supported on a Porous Polymer Matrix

Formic acid (FA) is considered one of the most promising carriers of clean and safe dihydrogen. This study highlights the potential of using poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) as a support for AuNPs to produce H2 through formic acid dehydrogenation (FAD). The developed synthesis method allows for precise control over the gold content by completely encapsulating AuNPs (4-6 nm) within the PPO matrix, ensuring a uniform distribution of nanoparticles with an active cubic morphology. In an aqueous solution (or a water/DMAc mixture), the catalyst exhibited high activity, generating H2 without producing CO, underscoring its high selectivity for dehydrogenation. At 105 °C, the catalyst showed a TOF of 360 molFA·molAu-1·h-1 and an activation energy of 39.3 ± 2.6 kJ·mol-1. By optimizing the formic acid concentration and gold loading, the system achieved an impressive TOF of 600 molFA·molAu-1·h-1, comparable to the best values reported in the literature. Notably, the AuNPs-PPO system facilitates the FAD reaction without requiring additional bases or modified supports. The reaction order of 0.81 ± 0.04 with respect to FA concentration indicates the rapid diffusion of the reagent within the polymer matrix without limiting its reactivity. Lastly, the AuNPs-PPO catalytic system has been demonstrated to be reusable.