We have investigated reduction of MXenes M2CO2 (M = Ti, V, Nb) surface by hydrogen using density functional theory and statistical physics methods. We have approximated lateral interactions between adsorbed hydrogen with simple pairwise potential. We have confirmed model stability via cross-validation. Adsorption isotherms are calculated using Metropolis Monte Carlo method. We have built analytical Langmuir-like approximation of calculated isotherms. Ordered phases with 1/3 and 2/3 ML coverage are visually observed at low temperatures. At temperatures above 300 K no obvious plateau is observed, and intermediate phases does not exist. We compared adsorptive properties of MXenes at the same external conditions.