The process of modification Ti2CTx MXene multilayer by hydrothermal synthesis of bulk hierarchically organized formations of Co(CO3)(0.5)(OH)center dot 0.11H(2)O has been studied. It is shown that under the chosen conditions the MXene is partially oxidized to form aggregates of titanium dioxide nanoparticles with a diameter of similar to 3-10 nm on its surface. The sensing properties of the obtained composite material at room temperature and relative humidity 65 +/- 3% to a wide range of gaseous analytes (50 ppm CO, benzene, acetone, ethanol, 2500 ppm H-2, CH4, 5% O-2, and 40 ppm NH3, NO2) have been investigated. Increased sensitivity has been found for the detection of 40 ppm NH3 and NO2: the responses have been found to be 91 and 63%, respectively. Some aspects of the detection mechanism are discussed. The results obtained show promising modification of multilayer MXene with semiconducting metal oxides and hierarchically formed bulk formations in order to improve its chemoresistive properties.