Engineering Co³⁺ cations in Co<inf>3</inf>O<inf>4</inf> multishelled microspheres by Mn doping: The roles of Co³⁺ and oxygen species for sensitive xylene detection

Heteroatom-doping is an effective approach for tuning the properties of transition metal oxides relevant to sensing. Here pristine Co3O4 and a series of Mn-doped Co3O4 multishelled microspheres have been prepared using amorphous-coordination-polymers (CPs). The method is essentially self-templated approach. The as-prepared materials have been used for the development of a gas sensor for detection of volatile organic compounds (VOCs). Results indicate that ∼3 at% Mn-doped Co3O4 multishelled microspheres exhibit enhanced sensing performances, when compared to the pristine Co3O4 multishelled microspheres. Mn cations doping decreases the hole concentration, and aids in the enhancement of the surface catalytic activity which is responsible for the observed performance towards VOCs oxidation.