H₂ and CO₂ uptake for hydrogen titanate (H₂Ti₃O₇) nanotubes and nanorods at ambient temperature and pressure

H₂ and CO₂ adsorption was investigated using pristine hydrogen titanate nanotube (HTNT) and nanorod (HTNR). HTNT and HTNR were modified with N-[3-(trimethoxysilyl)propyl]ethylene-diamine (TPEDA). Chemical linkage between an amine-containing organosilane and titanium on the surface of hydrogen titanate was confirmed with ²⁹Si CP-MAS NMR spectrum. H₂ and CO₂ uptake on several hydrogen titanate samples was obtained by a TGA Q50 analyzer in flowing N₂ gas of 40 mL/min and CO₂ gas of 60 mL/min at 25 °C and 1 atm. Pristine HTNT sample showed the highest H₂ uptake (i.e. ~12.5 mmol/g) on a TGA microbalance at 25 °C whereas amine-modified HTNT sample exhibited the highest CO₂ uptake (i.e. ~1.2 mmol/g) among all samples studied. CO₂/N₂ and H₂/N₂ selectivity for pristine and amine-modified HTNT samples was investigated by comparing the weight of the sample in flowing pure N₂ gas of 100 mL/min with above-mentioned mixed flows at 25 °C. Reversibility for CO₂ and H₂ uptake showed good performance for 9 cycles.