A mesoporous, transition metal oxide material having an average pore diameter ranging from 2 to 20 nm, a basic surface character defined by an isoelectric point>pH 7, and a specific surface area greater than 50 m2/g can be incorporated into a NOx sensing device as a NOx film. The mesoporous, transition metal oxide material includes an oxide of yttrium, lanthanum and/or cerium, and can be formed using a surfactant-templated self-assembly process.