A facile procedure for the synthesis of urchin-like Al2O3:Eu3+ hollow microsphere

•Urchin-like Al2O3:Eu3+ hollow microsphere is first and successful synthesized.•A novel efficient and environmentally friendly method was proposed.•The gel was prepared within several seconds.•The hollow microsphere precursors were prepared in a solvent-induced treatment.•This method might be extended to prepare other hollow-structured phosphor.