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

Abstract

Formic 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.

Navigating Copper-Atom-Pair Structural Effect inside a Porous Organic Polymer Cavity for Selective Hydrogenation of Biomass-Derived 5-Hydroxymethylfurfural

“…Our observation is fully consistent with the previous report by Wang et.al. 48 The corresponding pore size distributions (Fig. S10) calculated by nonlocal density functional theory modeling (NLDFT), demonstrated that the two respective POPs (C-POP and Cu@C-POP-B) display the equivalent broad distribution of mesopores in the range of ~2.3-6.4 nm.…”

Porous‐Organic‐Polymer‐Triggered Advancement of Sustainable Magnetic Efficient Catalyst for Chemoselective Hydrogenation of Cinnamaldehyde

“…Our observation is fully consistent with the previous report by Wang et.al. [36] The pore size distribution curve, as derived by the NLDFT (Non-Local-Density-Functional-Theory) fitting of the adsorption branches model (Figure 2c), clearly demonstrates the mesoporous nature of the three as-synthesized materials, with a distinct sharp peak predominately appearing in the 2-3 nm range. We also find a contraction of pore-width from 2.58, 2.4 & 2.07 nm, respectively, which could be attributed to the clogging of the pore-channels by the high density metal NPs.…”

Catalytic dehydrogenation of formic acid over palladium nanoparticles immobilized on fibrous mesoporous silica KCC-1

“…The TOF of 2 wt.% Pd/MSF-PDETA and 2 wt.% Pd/KIT-6-PDETA up to 20% conversion of FA were only 147 and 97 h -1 , respectively, and the TOF of 2 wt.% Pd/KCC-1-PDETA was almost 2 and 3 times higher than that of 2 wt.% Pd/MSF-PDETA and 2 wt.% Pd/KIT-6-PDETA, respectively. This difference is possibly due to the higher amount of the electron-rich nitrogen, smaller Pd particle size, and fibrous structure of KCC-1 that allowed more FA to access the catalytically active Pd sites [23,[31][32][33][34]. The nPd/nFA was kept close to 0.01 in all three catalysts, and therefore the Pd loading difference is not a factor when comparing the catalytic activities.…”