New fast synthesis of MOF-801 for water and hydrogen storage: Modulator effect and recycling options

Abstract

We report a new simple, fast, scalable technique for MOF-801 synthesis. The effect of modulators on crystallinity, size, and shape of particles, porosity, hydrogen and water uptake was traced using two mono-carboxylic acids with various concentrations. We also showed that slow heating and small grains in powder samples are optimal for fast water release at relatively low temperatures. Heating up to 60–80 °C is enough for complete water release in 40 min, while at 40 °C, after 100 min, water is retained in pores of the sorbent. It was shown that both acetic and formic acids enhance the properties of MOF-801 material. However, even without any additives, proposed synthesis conditions lead to porous, highly crystalline material with hydrogen uptake about 1.1 wt% at 750 mmHg and water uptake about 20% at ambient conditions. We proved that solvent from the synthesis of MOF-801 could be used at least four times without any degradation of the obtained sorbent in key properties.