One-step nanocasting synthesis of crystalline mesoporous CoO without using reducing agent

•It is a one-step nanocasting synthesis for mesoporous metal oxide with low oxidation status.•No reducing agent is used during the synthesis.•The obtained products possess highly ordered mesostructure with crystalline frameworks.

Ordered mesoporous crystalline CoO material was synthesized by a simple one-step nanocasting synthesis method using mesoporous silica as a hard template and cobalt nitrate Co(NO3)2·6H2O as the metal precursor. The cobalt nitrate precursor was impregnated inside the mesopore space of the hard template and was in-situ converted to Co3O4 in the first stage. Then it was further converted to CoO by directly heating up the intermediate to 740–780 °C for 2 h in an tube furnace under a constant nitrogen gas flow. No hydrogen or organic reducing agent was used. The obtained mesoporous CoO possesses ordered mesostructure and crystalline framework. This method provides a new facile and green strategy for the synthesis of mesoporous metal oxides with lower oxidation states.