Rationally Designed Double-Shell Dodecahedral Microreactors with Efficient Photoelectron Transfer: N-Doped-C-Encapsulated Ultrafine In2 O3 Nanoparticles.

Abstract

It is desirable but challenging to design efficient micro-/nanoreactors for chemical reactions. In this study, we have fabricated mesoporous double-shelled hollow microreactors composed of N-doped-C-coated ultrafine In2 O3 nanoparticles [N-C/In2 O3 HD (hollow dodecahedron)] by the thermolysis of a dodecahedral In-based framework in Ar atmosphere. The obtained N-C/In2 O3 HD exhibited excellent activity in the photocatalytic oxidative hydroxylation of a series of arylboronic acid substrates. This property can be attributed to its enhanced optical absorption and efficient separation of photo-generated electron-hole pairs, imparted by the unique structure and uniformly coated N-doped C layers. Furthermore, we found O2 .- to be the critical active species in the process of photocatalytic oxidative hydroxylation of arylboronic acids, and the formation mechanism of this radical is also proposed. Theoretical calculations further confirmed that the N-doped C layer serves as an electron acceptor and revealed the microscopic charge-carrier migration path through the In2 O3 /N-doped graphite interfaces. Thus, photo-generated electrons from hybrid states of In2 O3 , composed of In 5s and 2p orbitals, are transferred into the hybrid states of N-doped graphite, composed of C 2p and N 2p orbitals. The present study may be helpful for understanding and designing carbon-based micro-/nanoreactors for photocatalytic reactions, and may also be useful for investigating related micro-/nanoreactors.