Synthesis of spinous ZrO2 core–shell microspheres with good hydrogen storage properties by the pollen bio-template route

Spinous ZrO2 core–shell microspheres were synthesized by a hydrothermal method using pollen as a biotemplate. The samples were characterized by scanning electron microscopy, X-ray diffraction, energy-dispersive spectroscopy and the Brunauer–Emmett–Teller and Sieverts methods. The results show that, through controlling the temperature of calcinations, inorganic/organic heteromaterial semi-crystallized ZrO2 core–shell microspheres, inorganic/organic heteromaterial crystallized ZrO2 core–shell microspheres and pure crystallized ZrO2 core–shell microspheres can be achieved. The fabricated ZrO2 core–shell microspheres have an excellent hydrogen storage performance, reaching a hydrogen uptake of 1.521 wt.% at 298 K under 5 MPa.

Research highlights
► We demonstrate a facile biomimetic synthesis of spinous ZrO2 core-shell microspheres.
► Low-cost sunflower pollens were used as templates.
► For the first time, these microspheres have been employed as the materials for hydrogen storage.
► They have exhibited an excellent hydrogen storage performance at room temperature.