Highly Dispersed Ultrafine Palladium Nanoparticles Enabled by Functionalized Porous Organic Polymer for Additive‐Free Dehydrogenation of Formic Acid

Abstract

AbstractFormic acid (FA) is one of the most favorable chemical hydrogen storage materials for renewable energy transformation, the development of efficient heterogeneous catalysts for ultraclean H2 generation from FA in the absence of any alkalis or additives under mild conditions remains a major challenge. Here, we present a porous organic polymer containing triphenylamine (TPA) and 2,6‐bis(1,2,3‐triazol‐4‐yl)pyridyl (BTP) units (TB‐POP). The ultrafine palladium nanoparticles (NPs) with an average size of 1.5±0.6 nm can be facilely generated using convenient methods and are uniformly dispersed over the TB‐POP support. TPA and BTP units are homogeneously arranged in the host framework of TB‐POP; they serve as effective alternatives of basic sites to deprotonate FA into formate intermediates. Pd@TB‐POP has demonstrated remarkable catalytic activity and high selectivity in additive‐free dehydrogenation of aqueous FA solution. The value of initial turnover frequency (TOF) at 50 °C is as high as 1344 h−1. In sharp contrast, the use of sodium formate as an additive in the catalytic system results in the decrement of catalytic activity. The ultrafine palladium NPs are effectively immobilized during dehydrogenation of FA, and no aggregation of palladium NPs is observed after consecutive catalytic runs.