Palladium Nanoparticles Supported by Carboxylate-Functionalized Porous Organic Polymers for Additive-Free Hydrogen Generation from Formic Acid

Facile hydrogen generation from formic acid (FA) is a promising way of hydrogen storage and release in the fuel-cell-based hydrogen economy; the development of efficient heterogeneous catalyst systems for ultrapure H2 generation from FA in the absence of additives remains a major challenge. Herein, we present a prefunctionalized porous organic polymer (POP) containing 2,6-bis(1,2,3-triazol-4-yl)pyridyl (BTP) units and carboxylate groups. The terdentate BTP and hydrophilic carboxylate are homogeneously incorporated into the host framework of the POP. BTP units with strong chelating ability can effectively stabilize palladium nanoparticles for heterogeneous dehydrogenation of FA, whereas carboxylate not only increases polarity and dispersibility of the catalytic system in aqueous solutions but also functions as basic sites to facilitate the O–H bond dissociation. The catalytic system shows high catalytic activity, excellent stability and superior recyclability in H2 generation from aqueous FA without any additives.