Efficient photocatalytic water splitting through titanium silicalite stabilized CoO nanodots

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 g_CoO⁻¹ and 1390 μmol h⁻¹ g_CoO⁻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.