Methanol-controlled structural retention of metal-organic frameworks during binder-free pelletisation for enhanced hydrogen storage

Abstract

Metal-organic frameworks (MOFs) typically have structural degradation from mechanical compaction. Here, CuBTC was prepared through a sequential one-pot solid-state route and shaped by binder-free room-temperature uniaxial pelletisation. Methanol treatment duration was varied before compaction to determine its effect on structural and hydrogen-storage retention. CuBTC powder treated with methanol for 60 min retained 92.2% of its gravimetric hydrogen uptake after pelletisation, giving 3.54 wt% H 2 at 77 K and 20 bar. Longer methanol treatment reduced compaction-related losses in specific surface area, pore volume, and hydrogen uptake, though it also lowered isolated product yield from 40.0% (5 min) to 34.9% (60 min). The solid-state route produced approximately twice the recovered mass versus previous ball-milling synthesis. These results show that methanol treatment before binder-free pelletisation can improve the retention of CuBTC porosity and hydrogen uptake; further pressure-dependent and replicated mechanical testing is required to establish the compaction mechanism and scale-up performance.