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.