Self-assembly fabrication of titanium dioxide nanospheres-decorated tungsten diselenide hexagonal nanosheets for ethanol gas sensing application

•An ethanol gas sensor based on titanium dioxide/tungsten diselenide (TiO2/WSe2) nanocomposite was fabricated at first time.•The TiO2/WSe2 nanofilm sensor was prepared on an epoxy substrate via self-assembly technology.•The sensor exhibits high response, short response/recovery time and excellent selectivity for ethanol sensing.•The sensing mechanism was owing to the synergy effect p-n heterojunction of the TiO2/WSe2 nanostructure.