  Oxygen vacancies (VO), a common type of point defects in metal oxides
materials, play important roles on the physical and chemical properties. To
obtain stoichiometric oxide crystal, the pre-existing VO is always removed via
careful post-annealing treatment at high temperature in air or oxygen
atmosphere. However, the annealing conditions is difficult to control and the
removal of VO in bulk phase is restrained due to high energy barrier of VO
migration. Here, we selected VO2 crystal film as the model system and developed
an alternative annealing treatment aided by controllable hydrogen doping, which
can realizes effective removal of VO defects in VO2-{\delta} crystal at lower
temperature. This finding is attributed to the hydrogenation accelerated oxygen
vacancies recovery in VO2-{\delta} crystal. Theoretical calculations revealed
that the H-doping induced electrons are prone to accumulate around the oxygen
defects in VO2-{\delta} film, which facilitates the diffusion of VO and thus
makes it easier to be removed. The methodology is expected to be applied to
other metal oxides for oxygen-related point defects control.
