Heterogeneous photocatalysis represents a vibrant research field with possible applications ranging from water detoxification to solar fuel generation and chemical synthesis. Due to its simplicity, selective photooxidation of benzyl alcohols is often employed in photocatalysis as a model reaction for evaluation of the performance of various photocatalysts. A prominent example is the photocatalytic production of hydrogen peroxide, an attractive highvalue compound that can be employed as a fuel or a versatile and non-toxic oxidizing agent in various industrial processes, via reduction of dioxygen with concomitant photooxidation of benzyl alcohol to benzaldehyde. As a rule, a blank test intended to confirm the photocatalytic nature of the reaction is performed by irradiating the solution of benzyl alcohol or other electron donor in the absence of photocatalyst, thus ruling out possible photochemical reactions which the substrate might undergo. This approach, however, does not take into account the photochemical behaviour of products of partial oxidation of aromatic alcohols that are produced during irradiation of the suspension of photocatalysts in the substrate solution.