Polytriphenylamine Conjugated Microporous Polymers as Versatile Platforms for Tunable Hydrogen Storage

Hydrogen (H₂) as a fuel source presents a promising route toward decarbonization, though challenges in its storage remain significant. This study explores the synthesis and characterization of polytriphenylamine (PTPA) conjugated microporous polymers (CMPs) for H₂ storage. Utilizing a combination of Buchwald-Hartwig (BH) coupling, the Bristol-Xi'an Jiaotong (BXJ) approach, and variations in monomer reactive site stoichiometry, a polymer with specific surface areas in excess of 1150 m² g^-1 and micropore volume of 0.47 cm³ g^-1 is developed. H₂ storage capacities are measured, achieving excess gravimetric uptakes of 1.65 wt.% at 1 bar and 2.51 wt.% at 50 bar and 77 K, with total capacities reaching 4.40 wt.% at 100 bar and 77 K. Net adsorption isotherms reveal advantages to H₂ storage using PTPA adsorbents over traditional compression up to pressures of 10 bar at 77 K. High mass transfer coefficients of 4.95 min^-1 indicate a strong material affinity for H₂. This study highlights the impact of monomer ratio adjustments on the porosity and excess, total, and net H₂ adsorption capacities of PTPA-based CMPs, offering insights into the importance of a non-stoichiometric monomer concentration when developing efficient CMP-based H₂ storage materials.