A brief overview of compounds and materials exhibiting photocatalytic activity in reduction of molecular oxygen to hydrogen peroxide is given with focus on comparison of the performance of reported photocatalysts. The photocatalysts are treated in two major classes: the inorganic semiconductors, which include various metal oxides and chalcogenides, and carbon-based photocatalysts, which cover a wide range of carbon-based compounds from small organic molecules to graphene materials. The review is preceded by brief description of analytical techniques available for quantification of hydrogen peroxide formation.