Diffuse reflection spectroscopy and thermoluminescence are used to study the centers of photo-induced adsorption (photosorption) of hydrogen and oxygen on dispersed magnesium aluminate spinel. It is shown that F⁰ and F⁺-centers may photosorb oxygen molecules, and V-centers (O^- holes located at cation vacancies or [(Mg²⁺)_Al] centers typical of partially reversed spinels) dissociatively photosorb hydrogen molecules.