Formation of β-Ga2O3 nanorings from metal–organic frameworks and their high catalytic activity for epoxidation of alkenes

Here we report a novel synthesis of hollow high-quality β-Ga2O3 nanorings based on an interesting structural evolution from concave Ga-MOF nanodisks. The concave low-crystallinity nanodisks were constructed by non-classical crystallization with particle attachment aid. Further, we propose the evolution mechanism from the Ga-MOF nanostructure to the gallium oxide nanostructure based on the outward contraction of nanoparticles. This synthesis method is highly straightforward and provides high yields. It is important to note that the β-Ga2O3 nanorings exhibit good heterogeneous catalytic activity for epoxidation of alkenes. A new oxygen transfer pathway was illustrated to describe the catalytic process based on density functional theory.