Influence of synthesis temperature and synthesis activation strategies on the structure, porosity and hydrogen uptake of PET-derived MIL-53(Al)

Accumulation of post-consumer polyethylene terephthalate (PET) waste has become a significant planetary crisis requiring immediate recycling strategies for the upcycling of waste materials into high-value products. Herein, PET-derived MIL-53(Al) was synthesised at different temperatures and exposed to different activation strategies. Their influence on the material’s structural, textural and hydrogen adsorption properties was evaluated. The study revealed that the synthesis temperature and activation approach produced variations in the structural and textural properties of the PET-derived MIL-53(Al), with differences in hydrogen adsorption behaviour. The observed morphological differences suggest that the final material properties may reflect the combined influence of the synthesis temperature and activation procedure. The surface area for PET-derived MIL-53(Al) ranged from 269 to 1509 m 2 g − 1 . A decrease in surface area was observed with increasing synthesis temperature among samples activated using the same protocol. This suggests that both variables influenced the accessible porosity of the materials. Notable differences in hydrogen (H 2 ) uptake at 1 bar and 77 K were observed irrespective of comparable textural properties suggesting that hydrogen adsorption capacities may be influenced by factors beyond the accessible surface area.