Two-Dimensional Polyphenylene Networks with Tunable Micropores for Hydrogen Storage

Abstract

Micropores, especially ultramicropores with pore size smaller than 1 nm, play a crucial role in hydrogen storage. In this contribution, we report on bulk production of two-dimensional (2D) polyphenylene networks (PPNs) through a solution-based Wurtz reaction. A self-assembled mechanism is proposed for the formation of 2D PPNs based on molecular dynamics simulations. The morphology, structure, surface chemistry, and textural properties of the PPNs are greatly influenced by anneal treatment at 450−550 °C in terms of deep thermal dechlorination and cyclodechlorination. The annealed PPNs are featured with moderate specific surface area (S BET ) and wealthy micropores, which can be finely tuned by varying the anneal temperature. For PPNs, there is no direct correlation between the H 2 -uptake capacity and individual textural parameters such as S BET , S micropore , V total pore , V micropore , and V mesopore . The H 2 -uptake capacity is highly dependent on the distribution of ultramicropores and the pore volume of ultramicropores in the range of 0.5−0.8 nm (V ultramicropore 0.5−0.8nm ). The PPNs annealed at 500−520 °C, possessing moderate S BET (459.3−564.9 m 2 g −1 ), relatively high V ultramicropore 0.5−0.8nm , and ultramicropores concentrated at 0.69−0.71 nm, exhibit superior H 2 -storage capacity (4.28−5.39 mmol g −1 ) at 77 K and 1 atm.

Fast water transport and molecular sieving through ultrathin ordered conjugated-polymer-framework membranes

“…However, it remains challenging to reproduce the excellent transport properties of individual channels at a large scale for practical applications because of the difficulties of perfectly aligning or stacking these materials during the fabrication of membranes 3,24,25 . Two-dimensional (2D) porous carbonaceous materials, such as graphyne-n varieties, 2D polyphenylene networks, and 2D conjugated polymers, have also been explored for separation membranes [26][27][28] because they ideally have channels perpendicular to the molecular plane, and their diameters can be controlled through structural design. For example, theoretical studies predicted that graphdiyne (graphyne-2) could behave as an ideal 2D membrane for chemical and isotopic helium separation 26,29 or water filtration 30 .…”

Selective adsorption-involved formation of NMC532/PANI microparticles with high ageing resistance and improved electrochemical performance

“…The snapshot at the final 200 ps was considered as the final configuration. The total energy of simulation system was computed by using the Ewald method described in detail in reference [41].…”

Recent Advances and Reliable Assessment of Solid‐State Materials for Hydrogen Storage: A Step Forward toward a Sustainable H2 Economy

“…[ 102 ] Similarly, 2‐D polyphenylene networks (PPNs) exhibit H 2 uptake (4.28–5.39 mmol g –1 ) at 77 K and 1 bar, owing to the high volume of micropores ≈0.5–0.8 nm. [ 267 ] Gogotsi et al. [ 268 ] reported carbide‐derived carbons with SSA ≈ 3000 m 2 g −1 and gravimetric H 2 storage ≈ 4.7 wt% suggesting that the pores larger than 1.5 nm contribute least.…”

“…[102] Similarly, 2-D polyphenylene networks (PPNs) exhibit H 2 uptake (4.28-5.39 mmol g -1 ) at 77 K and 1 bar, owing to the high volume of micropores ≈0.5-0.8 nm. [267] Gogotsi et al [268] reported carbide-derived carbons with SSA ≈ 3000 m 2 g −1 and gravimetric H 2 storage ≈ 4.7 wt% suggesting that the pores larger than 1.5 nm contribute least. Linares-Solano et al [269] demonstrated activated carbons and fibers sorbents with 0.6 nm as optimal pore width which can hold two layers of adsorbed H 2 .…”