Sulfonic acid functionalized PVA/PVDF composite hollow microcapsules: Highly phenomenal & recyclable catalysts for sustainable hydrogen production

Hydrolysis of NaBH4 is a promising solution for on-site hydrogen energy generation. In the present paper, we report the preparation of hollow composite microcapsules made from sulfonic acid functionalized polyvinyl alcohol (SPVA) using simple chemical reaction followed by the addition of PVDF and applied for the hydrogen generation by means of hydrolysis of NaBH4. To develop series of microcapsules different ratios of water and isopropanol solvent systems such as 90:10, 80:20, 70:30, 60:40 and 50:50 were used and five types of composite microcapsules were prepared. The structure, morphology and properties of the prepared microcapsules were characterized with the assistance of various spectroscopic and analytical techniques. By employing prepared SPVA/PVDF hollow composite microcapsules as catalyst, hydrogen generation was studied by hydrolysis of NaBH4. Interestingly, SPVA/PVDF-Mcs-3 hollow composite microcapsules prepared using 70:30 ratio of water and isopropanol generated the highest amount of 570 mL hydrogen in 180 min at room temperature which can be attributed to the high porosity and less wall thickness. Additionally, various microcapsules and effect of different reaction parameters were also studied and discussed. The synthesized composite microcapsules have an imperative advantage of easy recovery and consecutive reusability for 10 cycles without destruction of activity and morphology. The fast kinetics, hydrogen generation efficiency and comparatively low activation energy (10.91 kJ mol(-1)) makes SPVA/PVDF composite microcapsules a promising candidate as catalyst for hydrogen generation by hydrolysis of NaBH4.