Efficient photocatalytic water splitting through titanium silicalite stabilized CoO nanodots

Nanoscale. 2019 Aug 29;11(34):15984-15990. doi: 10.1039/c9nr05057d.

Abstract

Water can be split into hydrogen (H2) and hydrogen peroxide (H2O2) in an environment-friendly manner through photocatalysis by CoO, which is a promising strategy to alleviate the energy crisis. However, the stability of CoO remains a great challenge because of the oxidation effect of the product H2O2. Herein, titanium silicalite-1 (TS-1) was employed as a framework to obtain and anchor monodisperse CoO nanodots, improve CoO photocatalytic performance, and efficiently separate the oxidizing species from CoO by adsorbing the resulting H2O2. As a result, TS-1 prevented CoO from aggregation, surface oxidation, and rapid inactivation. CoO-TS-1 showed H2 and H2O2 production rates of 1460 μmol h-1 gCoO-1 and 1390 μmol h-1 gCoO-1, respectively, with a high photostability for about 168 h. In addition, the efficiently harvested H2O2 was directly used in the oxidation of cyclohexane to cyclohexanol and cyclohexanone with a selectivity of up to 89.48%. This work paves a new way for the design of an efficient and stable photocatalyst as well as product utilization.